13 ms·

Why mobile web apps are slow

458 points by jacobparker 13y ago

hcarvalhoalves 13y ago
The trend towards retrofitting interactive applications to run inside the equivalent of a VM is just stupid, not only because of the obvious wastefulness of executing JS (given Moore's Law stopped). When dealing with a browser, you're limited to a broken interaction model (document? URL? back button?), a broken security model, one programming language with a weak API (that isn't equally supported between browsers either), and you have to abuse HTML into things it's not supposed to. It's a development experience that is subpar even by 90's standards. Add all that to the pedestrian performance, and I'm amazed this is still an option.
- untog 13y ago
  > The trend towards retrofitting interactive applications to run inside the equivalent of a VM is just stupid Well, Android does it. And in all honesty, when apps start getting complex they're just as bad. There's a reason URLs exist- it's to give a unique identifier to an item. Apps need to do that too, and end up having to fudge around launching and reaching a specific item.
  - hcarvalhoalves 13y ago
    > Well, Android does it. With the difference it uses a proper language designed to run on a VM in the first place - which is not the case with Javascript.
    - tracker1 13y ago
      I guess you missed that whole part of the article that discusses similar issues with GC and memory management with Android apps.
  - potatolicious 13y ago
    Apps have URLs also - even iOS, which is the weakest link in terms of inter-app interaction, has them. The difference here is that one platform requires shoehorning a URL into a non-document-centric use case, and the other one leaves it optional, for the developer to implement as he/she sees fit. If I'm using the Yelp app, I expect to be able to communicate a restaurant listing to someone else via a URL. But why is it that my alarm clock needs a URL? Or my phone dialer? The web was envisioned as interlinked documents, and for many parts of the web this is still very much the case (see: Amazon). For others this metaphor breaks down badly, and is the source of a great deal if hacks and kludges.
    - zanny 13y ago
      My linux kernel has a url. file:/boot/vmlinuz-linux So does my init daemon! file:/sbin/init Which is a symlink, so let's just specify a familiar program, and just throw on the proper file extension. file:/usr/bin/firefox.elf Still a url. To a program. If your executor supported file URIs you could run that. I could host it on an http server, and if I mounted it using webdav as a davfs2, I could access anything on that server the same way. You could write a python interpreter that can take a url to a python script to run: pythor http://github.com/some_repo/foo/script.py http://github.com/some_repo/foo/script.py A lot of programs already use URIs - I know KDE dolphin specifies all resource paths as URLs regardless of if they are local or remote, and it supports a buttload of URI schema. The qt5 QML engine specifies qml files to load by URI, so you can load remote qml applications in a browser that links in the qml runtime. I mean, we even have this nice syntax (that isn't pervasive or transparent) to supply arguments in a url with something like google.com/search?q=bacon which in bash-world would be google --query bacon or google -q=bacon. So what is missing from URLs from being uniform resource locators?
      - potatolicious 13y ago
        Not everything being a resource, for one, and not everything being naturally represented in a URI. It's possible to encode just about any information in a URI, it doesn't mean it isn't a kludge and a force-fit. Take a very, very simple (and common) use case: https://maps.google.com/maps?q=Newark+International+Airport,+Brewster+Road,+Newark,+NJ&hl=en&sll=40.697488,-73.979681&sspn=0.940177,1.685028&oq=newark+li&hq=Newark+International+Airport,+Brewster+Road,+Newark,+NJ&t=m&z=14 https://maps.google.com/maps?q=Newark+International+Airport,... Holy God would you look at that URL. It doesn't refer to a resource. In fact it refers to application state. This is a gross abuse of the whole concept of a URL, but the folks at Google aren't idiots - they know this. But the fact of the matter is that Google Maps is not document-based, and people have legitimate need to transport application state, independent of the semantics of the information they're looking for. Even something as simple as showing my friend the same map I'm looking at so we can talk about it requires bending the role of URIs wildly out of shape. Even better example: https://maps.google.com/maps?q=restaurants+around+Times+Square,+Broadway,+New+York,+NY&hl=en&sll=40.691572,-74.10347&sspn=0.235066,0.421257&oq=restaurants+around+times+square&hq=restaurants&hnear=Broadway,+New+York&t=m&z=16 https://maps.google.com/maps?q=restaurants+around+Times+Squa... One can argue that the previous link was clearly a reference to the airport, and there can be a URI for it (which wouldn't transport application state, substantially hobbling its use, but whatever). This link refers to "restaurants around Times Square", which isn't a logical entity, and whose relevance to the end user depends entirely on the application state being transported (e.g., zoom level, center point, filtered results, etc). Every time these insane-o URLs get brought up the URI-acolytes seem to end up suggesting that maybe we shouldn't have rich, interactive maps or such things, that we should force software into roles that play nicely with the document-centric, URI-friendly schemes. I for one believe that software serves users first, and methods to locate and specify information needs to adopt its users needs, not the other way around.
  - coldtea 13y ago
    >Well, Android does it. And that's why it has subpar apps compared to iOS when it comes to anything CPU intensive, high latency that makes it unsuitable for realtime audio/video apps, and you can see core Android engineers debating about why it's slow and such. And for games, devs have to fight the GC and implement stuff manually without allocations to work around it. So sure, it can run twitter clients and all kinds of everyday apps and web front-end apps quite OK. But for heavy CPU / realtime stuff that get us forward to novel use cases, not so much.
- williamcotton 13y ago
  What is broken about the security model?
  - hcarvalhoalves 13y ago
    It's easier to ask what is not broken. Check this presentation: http://www.slideshare.net/jgrahamc/javascript-security-2064979 http://www.slideshare.net/jgrahamc/javascript-security-20649...
    - myko 13y ago
      Interesting, any idea how that applies to something like Dart, when Dart is running in the Dartium (i.e., not compiled to JS)?
      - Ygg2 13y ago
        Dart doesn't exist in a mainstream browser yet. My guess, that some of those problems probably persist in Dart or maybe new, unforeseen ones are introduced.
        myko 13y ago
        Right, which is why I asked about Dartium (build of Chromium with DartVM built in). But yeah I guess only people really involved with Dart could answer this question properly.
- kgabis 13y ago
  This should be getting more upvotes, not downvotes.
  - Ygg2 13y ago
    Saying things like Moore law stopped gets a downvote from me. Moore law will stop, but it's not there yet. NOTE: Moore's law is concerned with number of transistors on a chip. That number has climbed, it's just split into several cores.
    - coldtea 13y ago
      >NOTE: Moore's law is concerned with number of transistors on a chip. That number has climbed, it's just split into several cores. We don't care about the pedantic interpretation of Moore law. We care about the mis-interpreation, that was a corellary of having single-core chips: that every 18 months computers got roughly twice as fast. This -- and this was the important attribute of Moore's law -- has stopped.
      - Ygg2 13y ago
        Who's we? You and author/OP? Because I've got good news for you, Moore's law corollary has merely slowed, not stopped. It will stop, just not now. I think Moore's law will work better on mobiles, because they are retreading known grounds and they are way further from reaching, real physical barriers than regular computers.
        coldtea 13y ago
        >Who's we? You and author/OP? Most people quoting Moore's law. That the misconception is more popular than his original statement, speaks for that.
        Ygg2 13y ago
        Yeah, marketing is a pita. It still doesn't negate the fact that even the corollary has slowed down, not stopped.
Apocryphon 13y ago
And how does this affect Firefox OS's performance?
- wasd 13y ago
  That's a great question. Does anyone have any anecdotal/benchmark evidence about the performance of Firefox OS?
  - lovskogen 13y ago
    I've tried it, and yes – it's sluggish.
    - holloway 13y ago
      It would be interesting to know if that was just the low-spec hardware that FirefoxOS targets. E.g. would a different approach also be relatively slow on that hardware.
purplelobster 13y ago
In my experience, slow DOM manipulation and various rendering glitches is the biggest barrier for most apps. Javascript performance is a big problem, but one affecting mostly apps that are processing heavy.
untog 13y ago
One minor caveat I'd add- JS is slow, but you don't always have to use it. I've had great results using a little JS coupled with hardware accelerated CSS transitions, animations, etc. Web apps are slower than native, that's undeniable, but they're only really slow when you port bad desktop practises ($("#home").animate() and the like) over to mobile.
- pachydermic 13y ago
  I'm just learning JS - I've had plenty of experience with more technical scripting languages, but I'm still a JS newbie. Is that a bad practice just because that kind of code is optimized for desktop use or is it just bad practice in general? Also, a broader topic I'm wondering about: JS and HTML seem pretty clumsy. I find it hard to believe that they're really how the majority of web pages run. Is there really no alternative? Or is it just the case that these tools are "good enough" and what really creates problems is bad code(rs)?
  - Pxtl 13y ago
    The tools are "good enough" but just barely, and very good coders have gone to herculean lengths to make them usable. The thing is that these spectacular achievements are available to all, making it into a decent platform. But naked HTML/CSS/Javascript is a document/hypertext engine perverted into a general-purpose platform. The thing is that the JS libs and practices used for desktop generally aren't mobile-friendly so even though everything works across all the platforms, it's not necessarily usable.
  - PavlovsCat 13y ago
    Is that a bad practice just because that kind of code is optimized for desktop use or is it just bad practice in general? I think the point here is that if you use Javascript to animate, that runs in, well, Javascript, and has to be called constantly. If you set a CSS property to achieve the same animation, the computations for it are done in native code. It still gets drawn the same way, but it's basically throwing away CPU for nothing (unless you do something that can't easily be replicated by CSS of course).
  - 13y ago
etler 13y ago
Am I the only person who's not a fan of the whole blogging with attitude trend?
- glogla 13y ago
  No, you're not. It detracts from the quality of the article.
- sjmulder 13y ago
  I agree, but here it’s backed up with evidence. Maybe the concerns are irrelevant in three years time with more advancements in hardware (though the author addresses that), the points made are valid.
- tedsanders 13y ago
  No, you're not alone. (One issue at play may be selection bias. The blog posts with attitudes cause a bigger reaction in readers, causing higher sharing, causing them to be read more, causing them to be overrepresented in what we see.)
- jbigelow76 13y ago
  I didn't pickup any attitude. The author is quite up front about his position but I didn't sense that he was belittling those that took an opposing pov, he simply thought they were wrong and attempted to provide evidence (the veracity of the evidence could, howeve, be debatable)
mhd 13y ago
My biggest "issue" with this generally rather decent article is that CPU-bound applications are rare. For the plethora of social, productivity and novelty apps it doesn't matter at all. Optimizing the graphical stack certainly matters, but that's mostly an infrastructure issue, i.e. already dependent on the native parts of the OS/framework. And consider who actually might be asking themselves this very question, native or webapp: The very same social/productivity/novelty websites and services who are looking how to best present their product on a mobile platform. And I'd wager a guess that sheer performance often isn't the deciding factor here , it's mostly about the native look. (And even seems to get less important, although I wonder whether iOS 7 could rekindle that) And that whole talk about GCs sound awefully familiar. Didn't we have the very same conversation in the mid-90s when Java came out? Also there's the good old alternating hard and soft layers. Hybrid webapps (with some native compoents to speed up and slim down things) could easily bridge the gap until the browser standards/APIs/hardware catches up. It's really not an all or nothing question, especially considering how many Android/iOS apps are basically WebViews with a tiny veneer of native buttons, preferences and background storage. Not that I like the web platform all that well, but let's be serious about the "depth" of web apps...
- hcarvalhoalves 13y ago
  > My biggest "issue" with this generally rather decent article is that CPU-bound applications are rare. For the plethora of social, productivity and novelty apps it doesn't matter at all. Or we can argue the other way around. Maybe we only have social, productivity and novelties over and over again because the limitations make those feasible?
  - mhd 13y ago
    Don't think so. We also have lots of games, which show that if you actually need the performance, people are willing to "drop down" to native. But the lion's share of the rest of the AppStore market could probably be replaced with webapps without CPUs being rent apart. But it won't look as native and you can't charge money for it as easily. We also have lots of social apps because, after all, most mobile devices are communication devices, so this comes naturally. Never mind that even when you consider full-fledged desktop apps and the backends of lots of web sites, there's not that much that is really CPU-bound (although it's getting back there with ubiquitous data mining, which is one of the main reason we're seeing a resurgence of native compilers) Two device sectors where this might be different are big tablets and low-end devices, pretty much both extremes of the mobile sector. Tablets used as full PC replacements would probably be the main users of the CPU-bound spreadsheet the author mentioned, as well as other almost-desktop apps that could require more resources, esp. considering multi-tasking. And they would be on for long stretches of time, so even if the quad-core processor could cope, it would be nice if it could cope for twice as long. And then we have low-end devices. When the Palm came out, all the people who learned 68k assembly on their Amigas/Ataris were in demand again, as there was little CPU and memory to spare. On the other hand currently the environment mostly targeted at those sectors is the one with the least support/demand for native: FirefoxOS. Which seems a bit weird at first, as they certainly could make use of every MIPS they can scrounge. But that's economics for you: If it's mostly cheap phones and (most likely) users with little income to spare on frivolous apps, why would you target it? On the other hand, you're probably writing a webapp for other devices, and FirefoxOS users can piggyback on that. Sometimes you rather have a slow app than none at all.
EdSharkey 13y ago
All the pain of HTML5 and dealing with legacy and inconsistent browser implementations and yes, even poor performance in JavaScript, is worth it because of the deployment model. Writing videogames in HTML5 on mobile is a tall order. I think it's more important as an industry that we reckon with how to effectively manage large teams developing huge applications in JS/HTML/CSS. I suppose that Facebook's development suffered from too many cooks in the kitchen, cruft building up, race conditions, etc. A video series I've seen tries to tackle scaling up JavaScript development by organizing development from an Agile/TDD angle, and I think with some success: http://www.letscodejavascript.com/ http://www.letscodejavascript.com/
Pxtl 13y ago
Nicely explains why I find Android's use of Java as the lingua franca utterly perplexing. GC has no place on a low-power interactive platform.
- Apocryphon 13y ago
  Maybe it's a trade-off to make developer adoption easy.
  - sjmulder 13y ago
    I’m not sure what alternatives they had. Of the top 10 languages on GitHub (https://github.com/languages https://github.com/languages), only C and C++ do not have garbage collection. Those are quite a different beast from Java of Objective-C. There’s a selection bias here but I struggle to come up with a popular non-GC, compiled language that operates on the same sort of level as Java or Objective-C.
    - Aqwis 13y ago
      Python's GC can be turned off.
      - Pxtl 13y ago
        Isn't python's GC reference-counted and deterministic anyways?
    - Roboprog 13y ago
      How about Pascal/Modula or FreePascal? It's almost as easy as Java (certainly less error prone as C), and almost as fast as C. Alas, I went to college in a time when they still taught Pascal, but then phased it out for C, which was more widely available on multiple platforms by the late 80s.
  - eonil 13y ago
    Actually exactly opposite happen on game developers.
azakai 13y ago
Well written article, but I have a few comments: 1. This is about JS speed. How important is JS speed in mobile apps, compared to rendering for example? That's the crucial question here, and I don't see any numbers on it. Rendering, after all, should be the same speed as a native app. 2. "Nothing terribly important has happened to CPU-bound JavaScript lately" - picking some benchmarks where there has been little change is possible. There are also benchmarks where there have been large changes. For example, many browsers now have incremental GC and background thread JITing. In some workloads these make a huge difference - but perhaps not on the old SunSpider benchmark. edit: As an example of a type of code that can run far faster today than before, see Box2D, which is a realistic codebase since many mobile games use it: http://j15r.com/blog/2013/07/05/Box2d_Addendum http://j15r.com/blog/2013/07/05/Box2d_Addendum
- ryanpetrich 13y ago
  Canvas is only marginally slower than the native 2D drawing APIs (it is a thin wrapper for Skia on Android and CoreGraphics on iOS), but it still uses only a single CPU thread for drawing on both platforms. To use the GPU, one has to turn to the -webkit-transform CSS property which, under certain circumstances, promotes the element to a GPU buffer. Only once WebGL becomes accessible will the mobile web have a drawing API that is more efficient than the standard windowing APIs.
amenod 13y ago
Coming from the world of C / Java / PHP / Python and similar I found ObjectiveC maddening at times. But ARC really shines. Brilliant idea and well executed too: virtually no work on programming side (well, a few small caveats about function names apply) and no performance penalty on user side. Win-win. Good job Apple.
RyanZAG 13y ago
Big part of the article focuses on garbage collection, low ram environments, and mobile devices. I'd just like to say that my S4 has 2GB of ram (yes, 2GB). More than likely, my next phone will have 3GB or 4GB of ram. As the author mentions, once you get to 3x-6x more physical ram than what you absolutely need, the garbage collector no longer slows down your device - in fact, it speeds it up. So I'm not sure that this is really that big a problem. RAM is one of the areas where mobile devices really are improving rapidly (the other being 3D). That said, the article was excellent. Props to the author.
- outworlder 13y ago
  Yes. However, an iOS device feels consistently faster while using much less memory (and processor cores!) The extra hardware eats the battery like crazy. This is all anecdotal, but its my impression after switching from an iPhone 4 to a Nexus.
- kogir 13y ago
  Actually, in general as memory use increases GC takes more time, not less. It's rare that the number of objects stays constant and they just get bigger, and more objects means longer and more difficult tracing. HN has this problem. If we use more than a quarter or third of available RAM GC destroys site performance. Switching to faster RAM helps, but adding more doesn't.
  - RyanZAG 13y ago
    Interesting point, but as per the chart[1] and discussion in the article, the relative memory footprint does have a big effect on performance. This is mostly felt when you get more complex object graphs. If the GC only needs to run once when you finish your calculation, it only needs to sweep once. If ram is limited and the GC is forced to run 100 times, then it must sweep 100 times. This is a lot of extra work and is the main reason why GC can be slow. In the case of HN, it sounds like you have more than enough RAM already, so you are not hitting the 'worse case' of GC that gets hit often in javascript on last generation mobile phones. The symptoms to the user are very similar to 'disk cache thrashing' and can be as bad as multiple second pauses. You're very correct in that increasing heap size too far is also a big problem, as running GC on 64GB of ram can take seconds - freezing up everything else while it runs. There are a number of guides on tuning the JVM on servers to avoid this. The new JVM GC algorithms are also very good at this situation by default, imo. Finally, on the issue of RAM speed: phones generally have a fixed amount of space dedicated to RAM - the 2GB chip on my S4 is the same as a 512MB chip on an older iPhone. This generally means that it is just as fast to access the 2GB of ram on an S4 compared to the 512MB on older devices. So at least on mobile, RAM speed is fairly closely related to RAM performance. I can't seem to find the benchmarks I saw earlier on this at present, anyone can confirm or deny with numbers? [1] http://sealedabstract.com/wp-content/uploads/2013/05/Screen-Shot-2013-05-14-at-10.15.29-PM.png http://sealedabstract.com/wp-content/uploads/2013/05/Screen-...
Joeri 13y ago
It's a well-researched article, but i doubt it will change anyone's mind. What i got as a take-away from this is that the sort of mobile apps that i work on can be done perfectly fine in javascript, because i did their desktop equivalents in ie7 on pc's with 512 mb ram. I'm reminded of the native vs web debates on the desktop. Everything the desktop guys said was true, with whole categories of apps essentially off-limits to web developers, and the remainder clearly and obviously inferior to their native counterparts. That didn't change, native apps still rule supreme in capability and usability. And yet the average person is using web apps the majority of the time (although that opinion admittedly depends on what you understand as average). The reason why that is translates to mobile. Everything this article says is true, and still mobile apps will be mostly web-based. There is no conflict between those facts.
- martingordon 13y ago
  Not sure if you know this, but iOS doesn't use a swap/page file. iOS will kill an app that uses a lot of memory because it values speed over stability and can very easily run out of RAM. In contrast, Windows won't kill an app when the system runs low of memory and will create more memory (however much slower that memory is than physical RAM) for the app to consume.
- coldtea 13y ago
  >That didn't change, native apps still rule supreme in capability and usability. And yet the average person is using web apps the majority of the time Those web apps most people use are trivial compared to the stuff we do on Desktop and Mobile. And the main reason people use them "the majority of time" is because they are huge time-sinks. E.g: Social apps like FB and Twitter, that translate to posting and reading text and images. Web mail, which translates to working with lists of text articles. Nothing much CPU intensive, in the way desktop/mobile apps are. As for the CPU intensive stuff, it's really still a novelty on the web. Nobody (== few people, less than 1% is the numbers I show), use Google Docs (and that's not even a full featured office suite anyway -- not to mention the spreadsheet for example takes lot of time even on my 2010 iMac/Chrome to apply stuff like conditional formatting). Even less people use something like online image editors and such. The only thing people really use on the web, and is CPU intensive are web games. And even those are more like 1995 quality desktop games.
baddox 13y ago
> BUT I THOUGHT V8 / MODERN JS HAD NEAR-C PERFORMANCE? > It depends on what you mean by “near”. If your C program executes in 10ms, then a 50ms JavaScript program would be “near-C” speed. If your C program executes in 10 seconds, a 50-second JavaScript program, for most ordinary people would probably not be near-C speed. I would actually reverse those two examples. A 10 second to 50 second jump probably wouldn't affect most user-facing programs that much, since it's either being done in the background or the user is staring at a progress bar. The UI of the application is probably (hopefully) already designed around the fact that there is a long-running process. But a 10ms to 50ms increase can be a big deal, since it's probably something that is intended to appear "instant" to the user.
MarkMc 13y ago
As an old Java programmer, I'm astounded that Apple are deprecating garbage collection on OS X. Is ARC really a better approach on the desktop?
- drewcrawford 13y ago
  No. But Apple has a shockingly small number of employees relative to other big software names, and they have had historically had much fewer third-party developers than other platforms. As a result, they have chosen to consolidate the mindshare onto one memory management technology rather than dilute the talent pool with two competing proposals. Given that iOS is much, much more popular than OS X, they have chosen to standardize on the technology that works best for the popular platform.
  - Roboprog 13y ago
    I would respectfully have to disagree. I've been programming for about 30 years, but finally broke down and bought my first Mac about a year ago. It's a nice platform, and the native apps are a joy to use, compared to the sludge that most Windows apps are. Oh, and it lets me do most of what I have been doing on Linux the last 18 years. Not quite everything, but pretty close. No matter how much you tweak and tune a GC, there are still going to be times when it destroys "locality" in a hierarchical memory system and causes some kind of pause. For a small form entry program, this is probably negligible. As the size of the program and/or its data grows, or the time constraints grow tighter, these pauses will become more and more unacceptable. Most of my work the last 10 years has been in Java, but the JVM is not the one true path to enlightenment. TMTOWTDI :-)
- pohl 13y ago
  Yes, insofar as their desktop operating system is also their laptop operating system. A prominent theme at WWDC this year was all of the changes they've been doing to improve power management. That garbage collection thread always running in the background is going to interfere with your efforts to save battery. A predictable strategy based on automatic reference counting, on the other hand...
- 13y ago
weland 13y ago
This is actually a very interesting post, and the first one of this level of documentation I've seen in a while. I also actually agree with most of the author's points. That being said, I think there's a big elephant in the room: the additional layers of complexity. Much of the younger generation in the web development community seems very far removed from the principles of computer engineering, to the point that there's a bunch of things you can hint at simply by common sense, yet they are opaque to them. For instance: 1. Performance hits aren't only due to slower "raw" data processing, they can also occur due to data representation -- think about cache hits, for instance. Your average mobile application's processing is more IO-bound than processor-bound. Unless you can guarantee that your data is being efficiently represented, you get a hit from that. 2. Since the applications are sandboxed, the amount of memory your runtime occupies is directly subtracted from the amount of memory your application gets. The more layers your runtime piles up that cannot be shared between applications -- the more memory you consume without actually offering any functionality. 3. Every additional layer needs some processing time. Writing into a buffer that gets efficiently transfered into video memory is always going to be slower than JIT-ing instructions that write something into a buffer that gets efficiently transfered into video memory -- at the very least the first time around. I'm not sure if someone is actually trying to say or (futilely) prove that a web application is going to be as fast as a native one (assuming, of course, the native environment is worth a fsck) -- that's something people would be able to predict easily. This isn't rocket science, as long as you leave the jQuery ivory tower every once in a while. The question of whether it's fast enough, on the other hand, is different, but I think it's eschewing the wider picture of where "fast" is in the "efficiency" forest. I honestly consider web applications that don't actually depend on widely, remotely accessible data for their function to be an inferior technical solution; a music player that is written as a web application but doesn't stream data from the Internet and doesn't even issue a single HTTP request to a remote server is, IMO, a badly engineered system, due to the additional technical complexity it involves (even if some of it is hidden). That being said, if I had to write a mobile application that should work on more than one platform (or if that platform were Android...), I'd do it as a web application for other reasons: 1. The fragmentation of mobile platforms is incredible. One can barely handle the fragmentation of the Android platform alone, where at least all you need to do is design a handful of UI versions of your app. Due to the closed nature of most of the mobile platforms, web applications are really the only (if inferior, shaggy and poorly-performing) way to write (mostly) portable applications instead of as many applications as platforms. 2. Some of the platforms are themselves economically untractable for smaller teams. Android is a prime example of that; even if we skip over the overengineering of the native API, the documentation is simply useless. The odds of having a hundred monkeys produce something on the same level of coherence and legibility as the Android API documentation by typing random letters on a hundred keyboards are so high, Google should consider hiring their local zoo for tech writing consultance. When you have deadlines to meet and limited funding to use (read: you're outside your parents' basement) for a mobile project, you can't always afford that kind of stuff. Technically superior, even when measurable in performance, isn't always "superior" in the real life. Sure, the fact that a programming environment with bare debugging capabilities, almost no profiling and static analysis capabilities to speak of and limited optimization options at best is the best you can get for mobile applications is sad, but I do hope it's just the difficult beginning of an otherwise productive application platform. I also don't think the fight is ever going to be resolved. Practical experience shows users' performance demands are endless: we're nearly thirty years from the first Macintosh, and yet modern computers boot slower and applications load slower than they did then. If thirty years haven't filled the users' thirst for good looks and performance, chances are another thirty years won't, either, so thirty years from now we'll still have people frustrated that web applications (or whatever cancerous growth we'll have then) aren't fast enough. Edit: there's also another point that I wanted to make, but I forgot about it while ranting the things above. It's related to this: > Whether or not this works out kind of hinges on your faith in Moore’s Law in the face of trying to power a chip on a 3-ounce battery. I am not a hardware engineer, but I once worked for a major semiconductor company, and the people there tell me that these days performance is mostly a function of your process (e.g., the thing they measure in “nanometers”). The iPhone 5′s impressive performance is due in no small part to a process shrink from 45nm to 32nm — a reduction of about a third. But to do it again, Apple would have to shrink to a 22nm process. The point the author is trying to make is valid IMHO -- Intel's processors do benefit from having a superior fabrication technology, but just like in the case above, "raw" performance is really just one of the trees in the "performance" view. First off, a really advanced, difficult manufacturing process isn't nice when you want massive production. ARM isn't even on 28 nm yet, which means that the production lines are cheaper; the process is also more reliable, and being able to keep the same manufacturing line in production for a longer time also means the whole thing costs less on a long term. It also works better when you have an economic model like ARM's -- you license your chips, rather than producing them. When you have a bunch of vendors competing for the same implementation of a standard, with many of them being able to afford the production tools they need, chances are you're going to see lower cost just from the competition effect. There's also the matter of power consumption, which isn't negligible at all, especially due to batteries being such nasty, difficult beasts (unfortunately, we suck at storing electrical energy). Overall, I think that within a year or two, once the amount of money shoved into mobile systems will reach its peak, we'll see a fairly slower rate of performance improvement on mobile platforms, at least in terms of raw processing power. Improvements will start coming from other areas.
williamcotton 13y ago
While I feel that most of the article is little more than reaching for straws, he does make some good points about memory management in Javascript and on mobile. Garbage collectors should be optional. I would really love to be able to handle my memory directly if possible, and while there are some things I can do related to object pooling, I lose control over that with closures and a more functional approach. I guess to counter my own argument here I will say that for most resource intensive things like simulations (call them games if you will), an object-oriented approach does a better job of modeling than a functional one. Game loops, sprites, bullets flying around... go OOP... and then use an object pool and limit your use of closures. Is it a pain in the ass? You bet, but so is having to manage the heap on your own. Now, as for the rest of the article, the author did a LOT to discredit himself insisting that JS performance will not increase over the next few years... dude, come on, winning isn't as important as learning and discussing, and you're clearly just trying to WIN an argument. This article is not very balanced. It is basically just saying that all software written for a VM is stupid. That the concept of Garbage Collection is an abomination. The truth is that VMs are incredibly successful and aren't going anywhere. I mean, look at the rise of VPS! Now compiled C and even machine code aren't running as fast as they could be! Run for the hills! Performance is not the be-all, end-all of computing. We're a social species and the reason that JS is the so successful has more to do with the fact that it is hosted in a VM based on open standards than anything else. So why have we moved to virtualization? Because it makes a LOT of sense. It's the same reason we invented compilers and higher-order languages in the first place... we're human. We are the ones writing and reading source code... the machines don't, they just blindly follow instructions. We choose to sacrifice speed for a more humanistic interaction with our machines, and that applies just as much to programmers as to the people who just use programs. These are very early days for mobile computing. You say you want to raise the level of discourse? Well then do it by writing articles that are more about discussing solutions than winning. For example, HTML5rocks.com (and yes, I am fully aware of the HTML5 marketing machine..) has been writing some good articles on memory management in Javascript, and that approach actually raises the level of discourse.
- eropple 13y ago
  I'm not sure how closely you actually read his post because he doesn't say anything you attribute to him about software written for VMs being stupid--in fact he explicitly states that it makes a lot of sense in desktop environments because it improves programmer productivity. He's got a heading, in all caps, saying "GC ON MOBILE IS NOT THE SAME ANIMAL AS GC ON THE DESKTOP", and he quotes, while indicating agreement with, guys like Herb Sutter and Miguel de Icaza explicitly stating that managed languages make tradeoffs for developer productivity. Which they do, and those tradeoffs don't really work on mobile (and won't until we see significantly improved memory density, among other things). Disagree with him if you want to--I'd like to, because I like the JVM and the CLR, but he has the weight of evidence on his side--but can we not make stuff up?
MatthewPhillips 13y ago
This article is weird. It starts off with a strong premise -- we need more fact-based arguments when discussing technology choices. Yes, agree! There are a fair amount of good points here, particularly about ARM's potential but he's very dismissive of counter points and seems to believe having lots of quotes is a substitute to a good argument. The section about garbage collection is especially unconvincing and, again, dismissive of counter points. He never really addresses Android or Windows Phone (which, by the way, he repeatedly mistakenly calls Windows Mobile -- which is right in line with the extreme iOS focus the article has). He mentions them, but then seems to think that a few quotes that show that, under some extreme circumstances -- mostly games -- the GC can be a problem on those platforms. But which is it, are all Java and C# Android/Windows Phone apps unacceptably slow or are some types of apps not really doable in those GC languages? This is important because a large part of his argument centers on GCs not working on mobile. I'd conclude that the article is overly defensive. To the point that the author repeatedly poisons-the-well of anyone who might potentially disagree. > we need to have conversations that at least appear to have a plausible basis in facts of some kind–benchmarks, journals, quotes from compiler authors, whatever. This is where I think the article falls apart. Appearing to be based on facts is what this article is about, but appearance just gets you talked about. It doesn't really move the conversation forward at all.
- rsynnott 13y ago
  > But which is it, are all Java and C# Android/Windows Phone apps unacceptably slow or are some types of apps not really doable in those GC languages? He didn't really say either; he pointed out (correctly) that for certain applications in a memory managed language, you'll want to essentially avoid using the GC, and you'll certainly have to be very cautious of it. The extreme case was old J2ME games, which usually worked by allocating all the memory they'd use as a large array at startup, and doing manual memory management thereafter. In general, you can do just about anything in a memory managed language, but in some cases, especially games, it may actually end up a lot more work than in a non-managed language.
  - spullara 13y ago
    There are two performance choices in GC languages: 1) don't allocate after initialization 2) only allocate per small time frame There is an issue that 2) is only really feasible in server settings and doesn't really work for clients. I buy his argument even though I don't wish to program under his restrictions.
kannanvijayan 13y ago
Disclaimer: I'm a JS JIT developer. The use of Sunspider performance to talk about JS application performance is unfortunate, and undermines a significant part of the argument made in the article. Sunspider is a great benchmark to use to talk about web _page_ performance. This is how JITs work: 1. Javascript code starts executing in a slow environment. 2. In this execution mode, a lot of overhead is spent collecting type information so that the hot code can be optimized. 3. After some period of time, the hot code is compiled with an optimizing compiler, which is a very expensive task. 4. The compiled code starts running. For example, in Mozilla's JS engine, these are the actual numbers associated with optimization: 1. A function starts off running in the interpreter 2. After it gets called 10 times (or a loop within it goes around 10 times), it gets compiled with the Baseline JIT, which performs heavyweight bytecode analysis on the javascript code, generates unoptimized machine code which is instrumented to acquire information about the executing JS. 3. After 1000 iterations (most of that running within Baseline jitcode), the function gets compiled with our optimizing compiler, IonMonkey. How does this relate to Sunspider? Well, if you actually run Sunspider, you'll notice that the entire benchmark takes about 0.2 seconds or less on a modern machine (about 1.5 seconds on a modern phone). It's an extremely tiny benchmark (in terms of computation heaviness). Comparatively, the Octane suite, while containing fewer benchmarks, actually takes 100 times or so longer to execute than sunspider. How many apps do you use that run for less than 1.5 seconds? This is the problem with using Sunspider to talk about app performance. Sunspider doesn't measure JIT performance very well at all. When JIT engines execute Sunspider, they spend a relatively large amount of that time just collecting the necessary information before they can start optimizing. Then, soon after we spend all that effort optimizing the code, the benchmark ends, without really taking advantage of all that fast code. Very often, JIT optimizations that speed up computationally heavy benchmarks actually regress Sunspider. This is because the optimizations add some extra weight to the initial analysis that happens before optimized code is generated. This hurts sunspider because the initial analysis section is much more heavily weighted than later optimized performance. Sunspider's runtime characteristics make it a good benchmark for measuring web PAGE performance. Web pages are much more likely to contain code that executes for short periods of time (a few ms), and then stops. But apps have much different runtime characteristics. Apps don't execute code for a few milliseconds and then stop. They run for dozens of seconds, minimally, and often minutes at a time. A JIT engine has much more opportunity to generate good optimized code, and have that optimized code taken advantage of over more of the execution time. It's unfortunate that such a fundamental misunderstanding of the characteristics and nature of optimized javascript is used to drive an argument about it.
fpgeek 13y ago
I think the author is making a big mistake in selling short the possibility of x86-class CPU performance on mobile. Perhaps it comes from his iOS focus, but he's just wrong about the difficulty of transitioning the mobile software ecosystem to x86. Android is there today and has been for over a year (as the reviews of last year's x86 smartphones make abundantly clear). And, as we all know, Android is the majority of the devices, by a large margin. It is true that iOS, Windows Phone and other platforms may have more trouble with an x86 transition, but so what? If Android makes a performance leap by moving to x86, other platforms will either find a way to keep up or they'll fall behind in the market. Either way, the mobile center-of-gravity will move towards x86-class CPU performance.
- alayne 13y ago
  Motorola's Atom based RAZR was slower than their ARM based one. The x86 architecture isn't doing anything for you on mobile and so far the reason Intel has struggled is because they couldn't compete on power consumption, a more important factor. Since desktops can burn power, they can run a lot more transistors and run them more quickly. I don't see mobile CPU performance catching up to desktops soon.
  - fpgeek 13y ago
    Here's a specific comparison of the Razr i vs the Razr M. http://www.engadget.com/2012/10/04/motorola-razr-i-review/ http://www.engadget.com/2012/10/04/motorola-razr-i-review/ Yes, the Razr i lost (mostly modestly) on 4 out of 5 performance benchmarks, but... 1. It modestly won on power consumption (9 hours vs 8). 2. Quoting from the review: "Aside from the benchmark results outlined above, the Medfield entry offered a marginally faster response to most actions." 3. Drawing CPU vs CPU conclusions from several benchmarks is complicated by one of the other differences between the two phones - the GPU (which is mostly an orthogonal question). Oh, and then there's that benchmark the RAZR i won, by almost a factor of 2: SunSpider. While SunSpider has its limitations, it's the most still relevant benchmark of the set to the discussion we're having right now. And this performance difference has real-world consequences (another quote): "The results remain largely unchanged, but after spending a week with the device, we'd like to add that the web browser still gives a superb performance." Intel's problem in mobile has never been performance (except when self-inflicted and they're past that). As of last year, it isn't power consumption either. Today, Intel's last problem is modems (specifically LTE modems), and they're hard at work on that one too: http://newsroom.intel.com/community/intel_newsroom/blog/2013/06/04/intel-is-inside-the-new-samsung-galaxy-tab-3-101-inch http://newsroom.intel.com/community/intel_newsroom/blog/2013... Finally, Intel's tagline for Silvermont is "~3X the Performance or ~5X Lower Power". If they pull that off and integrate it with a competitive LTE modem (and those are both still significant ifs even though today's indications look good), that's a ~2X SunSpider combined with a separate ~3X CPU leap. That won't just multiply because the bottlenecks will shift and SunSpider is the wrong benchmark CPU-bound JavaScript anyway. But however it plays out, that still would close a big chunk of the mobile-desktop JavaScript performance gap, especially when you notice that this year's Haswell focused on power consumption and, at best, only offers a small performance bump over last year's Ivy Bridge. It isn't a lock, but it isn't a possibility to dismiss either.
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6ren 13y ago
Why not increase RAM x5?
- chris_mahan 13y ago
  RAM has to be powered.
  - 6ren 13y ago
    I hadn't considered power, thinking it would be minimal. Research agrees - but task dependent: The RAM, audio and ﬂash subsystems consistently showed the lowest power consumption. ...RAM power can exceed CPU power in certain workloads, but in practical situations, CPU power overshadows RAM by a factor of two or more. [p.11, graph on p.5] from 2010: An Analysis of Power Consumption in a Smartphone https://docs.google.com/viewer?url=https%3A%2F%2Fwww.usenix.org%2Fevent%2Fusenix10%2Ftech%2Ffull_papers%2FCarroll.pdf https://docs.google.com/viewer?url=https%3A%2F%2Fwww.usenix....
6ren 13y ago
Aside: in some circumstances, JIT can be faster than compiled, by recompiling based on run-time usage, and so choosing optimizations appropriate to execution flow.
6ren 13y ago
Why don't gc languages have optional memory management - include free(), so there's less work for the gc?
- lalc 13y ago
  Do you know what GC does?
- eonil 13y ago
  Maybe Microsoft C++/CLI?
- rsynnott 13y ago
  That would tend to make the GC more complicated, not less. Some memory managed VMs do allow you to allocate outside the GC'd heap, though; see java.nio.ByteBuffer in Java (or sun.misc.unsafe, if you're very daring)
modeless 13y ago
The use of SunSpider to argue that CPU-bound JavaScript performance has not improved since 2010 is simply wrong. What SunSpider does is not at all representative of what CPU-bound JavaScript in a modern web app does. V8 and SpiderMonkey have significantly improved performance on real app code since 2010, despite the unchanged SunSpider scores. I say this as a developer on a large and heavily CPU-bound JavaScript app. The dismissal of asm.js is wrong too, for many reasons. Browsers don't need to support it explicitly necessarily. GC pauses are eliminated regardless of browser support, and most JavaScript optimizations will help asm.js too. The elimination of GC is not the only benefit, or even the main one really (the main benefit is the elimination of polymorphism, improving JIT performance and allowing AOT compilation). The assertion that it's not "really" JavaScript is irrelevant to the question of whether it can speed up web apps or not. All that said, I really appreciate the article and the discussion it's sparked.
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lnanek2 13y ago
Some of these comments are very out of date. Android hasn't had a stop the world garbage collector that caused 200-300ms delays since before Android 2.3. It's true I had to avoid dereferencing anything in the game loop back before then, but I don't know anyone who codes like that anymore on Android and I know hundreds of developers...
- deleted 13y ago
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- epochwolf 13y ago
  And most android devices are on what version of android?
  - Jare 13y ago
    2.3 and above, according to Unity's hardware stats at http://stats.unity3d.com/mobile/index.html http://stats.unity3d.com/mobile/index.html
tedsanders 13y ago
Off-topic nitpick: I believe this sentence is untrue: "And Intel had to invent a whole new kind of transistor since the ordinary kind doesn’t work at 22nm scale." First, regular transistors do work at the 22nm scale (but tri-gate/finfet transistors work better, if you can pattern them reliably). Also, Intel didn't invent the tri-gate/finfet transistor. They just got it to production first.
- erhardm 13y ago
  To be fair, he said he's not a hardware guy. But he also is right, FinFet transistors are better for power consumption and that's really important in mobile devices
bitcuration 13y ago
Wish author has explained why Flipboard which is built in html5/javascript is not awfully slow like linkedin.
- eonil 13y ago
  Any clue that it's actually been implemented with HTML5/JS?
aconz2 13y ago
over 180 network requests and over 40 scripts, maybe the author needs to learn a bit more about best practices on the web before standing on his soapbox. and quit bolding things mid-sentence.
cromwellian 13y ago
I generally agree with his comments on JS and memory management, for stuff like games, or image processing, but IMHO, these are not, in general, the reason why people have this notion that "mobile web apps are slow". There aren't a lot of games or Instagram apps written in JS, what there are, are lots of content oriented and form processing based mobile web sites, like your Bank, or your insurance company, or Slate or HuffingtonPost, and it is these sites which are prompting you to download native versions, and it is people's experience of these lightweight (non-CPU dependent) sites as being slow which I think needs addressing. I would break it down into three effects: 1) startup latency 2) excessive repaints/not leveraging compositor/jank 3) 'uncanny valley' issues where web emulations of native widgets don't match 100% with the feel of system widgets. The basic documented-oriented part of the mobile web is a lot slower than something like UIKit/TextKit in iOS, so the time to launch even a basic form to display some data, or a few paragraphs, and smoothly scroll it, with all rendering effects, and without layout or repaint jank, is just more work on the mobile web to optimize for, and therefore, many developers don't do it, or aren't aware of how to do it, leading to enduser perception that "mobile web is slow" I'd summarize my point of view as: NaCl/PNaCL won't solve our problems (although it is still a good idea to do them)
ashcairo 13y ago
Great post! I'm a huge C++/Anti-GC/Games developer here. Few notes. On performance, most of the time, I'm GPU bound when writing games. In this JavaScript based game for iOS: http://imgur.com/XQdGKHw,swTBC9T#0 http://imgur.com/XQdGKHw,swTBC9T#0 I'm getting 11ms used up on the CPU and 29ms used up on the GPU: http://imgur.com/XQdGKHw,swTBC9T#1 http://imgur.com/XQdGKHw,swTBC9T#1 That's 11ms using iOS JavaScript which isn't JIT optimised. Granted CPU will go crazy if I try running advanced Physics using JavaScript, but I tend to push Math intensive functions to C++ using a hybrid approach. On GC, I'm not a fan, I like managing my memory. However, UnrealEngine, which is super-awesome, has a built in garbage collector. In my experience with it, whenever someone tries to blame its GC for performance/memory abuse, to my dissatisfaction, the problem usually lies elsewhere. Main reason I've full on switched to the JavaScript world for development is its ability to re-interpret code on the fly. Allowing me to write and tweak, code/ui/design changes in real-time across multiple-devices.
coldtea 13y ago
I have to say, any minor quibbles aside, this is the best modern-day, non-academic article I've read on HN since forever.
gwu78 13y ago
Has anyone in mobile OS and mobile apps ever questioned the assumptions that Java must be used and/or a scripting language must be used, e.g., Javascript? What if we had a mobile OS and a mobile app that was 100% Java free and only ran compiled code (i.e., that compiles to ARM assembly)? Under the Steve Jobs theory of computers, everything should be "fast enough" just as it is. Because Moore's law and the increasing computing power of hardware should allow us to focus entirely on making everything as user friendly (including develeoper friendly) as possible without having regard for software efficiency. Watch for example the 1980 documentary "Entrepreneur" to see Jobs state this while the cameras follow him around during a NeXT retreat in Pebble Beach. But I've also seen Hertzfeld say Jobs for example pushed hard for him to try to reduce boot times on the Mac. This is of course is firmly in the realm of software (bootloader and kernel) so it would seem a conflict of ideas. Software efficiency does matter sometimes. Even when the focus is user friendliness and user experience. Jobs also said things back in the day about "the line between hardware and software" becoming blurred. I find this difficut to agree with. But then I'm not called a genius like he was. There are no doubt competent C and ARM assembly programmers out there. I've seen them doing embedded work and making games. Alas, I do not think they are by and large involved with working on the popular mobile OS's. Instead the focus seems to be on people who prefer to work with virtual machines and scripting languages.
- Moto7451 13y ago
  Has anyone in mobile OS and mobile apps ever questioned the assumptions that Java must be used and/or a scripting language must be used, e.g., Javascript? What if we had a mobile OS and a mobile app that was 100% Java free and only ran compiled code (i.e., that compiles to ARM assembly)? First, it's a bit pedantic but JIT VMs still compile down to ARM assembly on an ARM device. They basically optimize away the overhead of interpreting their target language. That said, what you're getting at is how Palm and Windows Mobile did it (for the most part, there is/was .Net for Windows CE) and how iOS does it now. Ubuntu Mobile and Win Phone 8 offer native toolsets in addition to GC/managed runtimes. I don't think its an assumption at all that mobile devices have to use Java. J2ME didn't exactly take over the world, and that had the advantage of hardware acceleration in the form of ARM Jazelle[1]. What has happened is as hardware gets faster/cheaper, Java, .Net, JS, etc become a better fit for development on mobile devices. On the Desktop we have stupidly powerful machines that can generally brute force their way through the inherent overhead of interpreted/JITed/VMed languages. On mobile however, we're not there yet. [1]http://en.wikipedia.org/wiki/Jazelle http://en.wikipedia.org/wiki/Jazelle
andrewgleave 13y ago
Anyone interested in optimising their mobile web applications should watch Apple's Safari tracks from this year's WWDC. They have plenty of informative advice on how to improve general performance and how to use tools WebKit provides to measure performance problems. Some key take aways: Avoid using libraries (like jQuery). It will reduce memory consumption significantly. Be careful how often you're invalidating style info and forcing recomuptation Avoid using scroll handlers to do layout (especially when you're likely to inadvertently invalidate styles at the same time)
glogla 13y ago
I like how he says that "mobile web apps are slow and always will be" (not a direct quote), but then dismisses asm.js as "it woudn't be a JavaScript anymore" so it doesn't count. The point of asm.js (if I understand it correctly) is that you can use JavaScript in way similar to Python -- you can make your application in high-level language, and then, after profiling, rewrite the performance critical parts into lower-level, less powerful, but faster language. That means, it still is "web app" but it can perform reasonably.
Roboprog 13y ago
I really liked this article: I think he was very methodical in challenging current dogma that GC/VM operations can be made as fast or faster than slightly lower level approaches. For the curious, I have a simple benchmark program that focuses on string manipulation (and deliberately creates many temp string objects, like a real app would) in various languages. If anybody wants to download and try it on the latest version of their favorite languages on the host-de-jure, go for it! https://github.com/roboprog/mp_bench https://github.com/roboprog/mp_bench

458 points by jacobparker 13y ago

The trend towards retrofitting interactive applications to run inside the equivalent of a VM is just stupid, not only because of the obvious wastefulness of executing JS (given Moore's Law stopped). When dealing with a browser, you're limited to a broken interaction model (document? URL? back button?), a broken security model, one programming language with a weak API (that isn't equally supported between browsers either), and you have to abuse HTML into things it's not supposed to. It's a development experience that is subpar even by 90's standards. Add all that to the pedestrian performance, and I'm amazed this is still an option.

untog 13y ago
> The trend towards retrofitting interactive applications to run inside the equivalent of a VM is just stupid Well, Android does it. And in all honesty, when apps start getting complex they're just as bad. There's a reason URLs exist- it's to give a unique identifier to an item. Apps need to do that too, and end up having to fudge around launching and reaching a specific item.
- hcarvalhoalves 13y ago
  > Well, Android does it. With the difference it uses a proper language designed to run on a VM in the first place - which is not the case with Javascript.
  - tracker1 13y ago
    I guess you missed that whole part of the article that discusses similar issues with GC and memory management with Android apps.
- potatolicious 13y ago
  Apps have URLs also - even iOS, which is the weakest link in terms of inter-app interaction, has them. The difference here is that one platform requires shoehorning a URL into a non-document-centric use case, and the other one leaves it optional, for the developer to implement as he/she sees fit. If I'm using the Yelp app, I expect to be able to communicate a restaurant listing to someone else via a URL. But why is it that my alarm clock needs a URL? Or my phone dialer? The web was envisioned as interlinked documents, and for many parts of the web this is still very much the case (see: Amazon). For others this metaphor breaks down badly, and is the source of a great deal if hacks and kludges.
  - zanny 13y ago
    My linux kernel has a url. file:/boot/vmlinuz-linux So does my init daemon! file:/sbin/init Which is a symlink, so let's just specify a familiar program, and just throw on the proper file extension. file:/usr/bin/firefox.elf Still a url. To a program. If your executor supported file URIs you could run that. I could host it on an http server, and if I mounted it using webdav as a davfs2, I could access anything on that server the same way. You could write a python interpreter that can take a url to a python script to run: pythor http://github.com/some_repo/foo/script.py http://github.com/some_repo/foo/script.py A lot of programs already use URIs - I know KDE dolphin specifies all resource paths as URLs regardless of if they are local or remote, and it supports a buttload of URI schema. The qt5 QML engine specifies qml files to load by URI, so you can load remote qml applications in a browser that links in the qml runtime. I mean, we even have this nice syntax (that isn't pervasive or transparent) to supply arguments in a url with something like google.com/search?q=bacon which in bash-world would be google --query bacon or google -q=bacon. So what is missing from URLs from being uniform resource locators?
    - potatolicious 13y ago
      Not everything being a resource, for one, and not everything being naturally represented in a URI. It's possible to encode just about any information in a URI, it doesn't mean it isn't a kludge and a force-fit. Take a very, very simple (and common) use case: https://maps.google.com/maps?q=Newark+International+Airport,+Brewster+Road,+Newark,+NJ&hl=en&sll=40.697488,-73.979681&sspn=0.940177,1.685028&oq=newark+li&hq=Newark+International+Airport,+Brewster+Road,+Newark,+NJ&t=m&z=14 https://maps.google.com/maps?q=Newark+International+Airport,... Holy God would you look at that URL. It doesn't refer to a resource. In fact it refers to application state. This is a gross abuse of the whole concept of a URL, but the folks at Google aren't idiots - they know this. But the fact of the matter is that Google Maps is not document-based, and people have legitimate need to transport application state, independent of the semantics of the information they're looking for. Even something as simple as showing my friend the same map I'm looking at so we can talk about it requires bending the role of URIs wildly out of shape. Even better example: https://maps.google.com/maps?q=restaurants+around+Times+Square,+Broadway,+New+York,+NY&hl=en&sll=40.691572,-74.10347&sspn=0.235066,0.421257&oq=restaurants+around+times+square&hq=restaurants&hnear=Broadway,+New+York&t=m&z=16 https://maps.google.com/maps?q=restaurants+around+Times+Squa... One can argue that the previous link was clearly a reference to the airport, and there can be a URI for it (which wouldn't transport application state, substantially hobbling its use, but whatever). This link refers to "restaurants around Times Square", which isn't a logical entity, and whose relevance to the end user depends entirely on the application state being transported (e.g., zoom level, center point, filtered results, etc). Every time these insane-o URLs get brought up the URI-acolytes seem to end up suggesting that maybe we shouldn't have rich, interactive maps or such things, that we should force software into roles that play nicely with the document-centric, URI-friendly schemes. I for one believe that software serves users first, and methods to locate and specify information needs to adopt its users needs, not the other way around.
- coldtea 13y ago
  >Well, Android does it. And that's why it has subpar apps compared to iOS when it comes to anything CPU intensive, high latency that makes it unsuitable for realtime audio/video apps, and you can see core Android engineers debating about why it's slow and such. And for games, devs have to fight the GC and implement stuff manually without allocations to work around it. So sure, it can run twitter clients and all kinds of everyday apps and web front-end apps quite OK. But for heavy CPU / realtime stuff that get us forward to novel use cases, not so much.
williamcotton 13y ago
What is broken about the security model?
- hcarvalhoalves 13y ago
  It's easier to ask what is not broken. Check this presentation: http://www.slideshare.net/jgrahamc/javascript-security-2064979 http://www.slideshare.net/jgrahamc/javascript-security-20649...
  - myko 13y ago
    Interesting, any idea how that applies to something like Dart, when Dart is running in the Dartium (i.e., not compiled to JS)?
    - Ygg2 13y ago
      Dart doesn't exist in a mainstream browser yet. My guess, that some of those problems probably persist in Dart or maybe new, unforeseen ones are introduced.
      - myko 13y ago
        Right, which is why I asked about Dartium (build of Chromium with DartVM built in). But yeah I guess only people really involved with Dart could answer this question properly.
kgabis 13y ago
This should be getting more upvotes, not downvotes.
- Ygg2 13y ago
  Saying things like Moore law stopped gets a downvote from me. Moore law will stop, but it's not there yet. NOTE: Moore's law is concerned with number of transistors on a chip. That number has climbed, it's just split into several cores.
  - coldtea 13y ago
    >NOTE: Moore's law is concerned with number of transistors on a chip. That number has climbed, it's just split into several cores. We don't care about the pedantic interpretation of Moore law. We care about the mis-interpreation, that was a corellary of having single-core chips: that every 18 months computers got roughly twice as fast. This -- and this was the important attribute of Moore's law -- has stopped.
    - Ygg2 13y ago
      Who's we? You and author/OP? Because I've got good news for you, Moore's law corollary has merely slowed, not stopped. It will stop, just not now. I think Moore's law will work better on mobiles, because they are retreading known grounds and they are way further from reaching, real physical barriers than regular computers.
      - coldtea 13y ago
        >Who's we? You and author/OP? Most people quoting Moore's law. That the misconception is more popular than his original statement, speaks for that.
        Ygg2 13y ago
        Yeah, marketing is a pita. It still doesn't negate the fact that even the corollary has slowed down, not stopped.

Apocryphon 13y ago

And how does this affect Firefox OS's performance?

wasd 13y ago
That's a great question. Does anyone have any anecdotal/benchmark evidence about the performance of Firefox OS?
- lovskogen 13y ago
  I've tried it, and yes – it's sluggish.
  - holloway 13y ago
    It would be interesting to know if that was just the low-spec hardware that FirefoxOS targets. E.g. would a different approach also be relatively slow on that hardware.

purplelobster 13y ago

In my experience, slow DOM manipulation and various rendering glitches is the biggest barrier for most apps. Javascript performance is a big problem, but one affecting mostly apps that are processing heavy.

untog 13y ago

One minor caveat I'd add- JS is slow, but you don't always have to use it. I've had great results using a little JS coupled with hardware accelerated CSS transitions, animations, etc. Web apps are slower than native, that's undeniable, but they're only really slow when you port bad desktop practises ($("#home").animate() and the like) over to mobile.

pachydermic 13y ago
I'm just learning JS - I've had plenty of experience with more technical scripting languages, but I'm still a JS newbie. Is that a bad practice just because that kind of code is optimized for desktop use or is it just bad practice in general? Also, a broader topic I'm wondering about: JS and HTML seem pretty clumsy. I find it hard to believe that they're really how the majority of web pages run. Is there really no alternative? Or is it just the case that these tools are "good enough" and what really creates problems is bad code(rs)?
- Pxtl 13y ago
  The tools are "good enough" but just barely, and very good coders have gone to herculean lengths to make them usable. The thing is that these spectacular achievements are available to all, making it into a decent platform. But naked HTML/CSS/Javascript is a document/hypertext engine perverted into a general-purpose platform. The thing is that the JS libs and practices used for desktop generally aren't mobile-friendly so even though everything works across all the platforms, it's not necessarily usable.
- PavlovsCat 13y ago
  Is that a bad practice just because that kind of code is optimized for desktop use or is it just bad practice in general? I think the point here is that if you use Javascript to animate, that runs in, well, Javascript, and has to be called constantly. If you set a CSS property to achieve the same animation, the computations for it are done in native code. It still gets drawn the same way, but it's basically throwing away CPU for nothing (unless you do something that can't easily be replicated by CSS of course).
- 13y ago

etler 13y ago

Am I the only person who's not a fan of the whole blogging with attitude trend?

glogla 13y ago
No, you're not. It detracts from the quality of the article.
sjmulder 13y ago
I agree, but here it’s backed up with evidence. Maybe the concerns are irrelevant in three years time with more advancements in hardware (though the author addresses that), the points made are valid.
tedsanders 13y ago
No, you're not alone. (One issue at play may be selection bias. The blog posts with attitudes cause a bigger reaction in readers, causing higher sharing, causing them to be read more, causing them to be overrepresented in what we see.)
jbigelow76 13y ago
I didn't pickup any attitude. The author is quite up front about his position but I didn't sense that he was belittling those that took an opposing pov, he simply thought they were wrong and attempted to provide evidence (the veracity of the evidence could, howeve, be debatable)

mhd 13y ago

My biggest "issue" with this generally rather decent article is that CPU-bound applications are rare. For the plethora of social, productivity and novelty apps it doesn't matter at all. Optimizing the graphical stack certainly matters, but that's mostly an infrastructure issue, i.e. already dependent on the native parts of the OS/framework. And consider who actually might be asking themselves this very question, native or webapp: The very same social/productivity/novelty websites and services who are looking how to best present their product on a mobile platform. And I'd wager a guess that sheer performance often isn't the deciding factor here , it's mostly about the native look. (And even seems to get less important, although I wonder whether iOS 7 could rekindle that) And that whole talk about GCs sound awefully familiar. Didn't we have the very same conversation in the mid-90s when Java came out? Also there's the good old alternating hard and soft layers. Hybrid webapps (with some native compoents to speed up and slim down things) could easily bridge the gap until the browser standards/APIs/hardware catches up. It's really not an all or nothing question, especially considering how many Android/iOS apps are basically WebViews with a tiny veneer of native buttons, preferences and background storage. Not that I like the web platform all that well, but let's be serious about the "depth" of web apps...

hcarvalhoalves 13y ago
> My biggest "issue" with this generally rather decent article is that CPU-bound applications are rare. For the plethora of social, productivity and novelty apps it doesn't matter at all. Or we can argue the other way around. Maybe we only have social, productivity and novelties over and over again because the limitations make those feasible?
- mhd 13y ago
  Don't think so. We also have lots of games, which show that if you actually need the performance, people are willing to "drop down" to native. But the lion's share of the rest of the AppStore market could probably be replaced with webapps without CPUs being rent apart. But it won't look as native and you can't charge money for it as easily. We also have lots of social apps because, after all, most mobile devices are communication devices, so this comes naturally. Never mind that even when you consider full-fledged desktop apps and the backends of lots of web sites, there's not that much that is really CPU-bound (although it's getting back there with ubiquitous data mining, which is one of the main reason we're seeing a resurgence of native compilers) Two device sectors where this might be different are big tablets and low-end devices, pretty much both extremes of the mobile sector. Tablets used as full PC replacements would probably be the main users of the CPU-bound spreadsheet the author mentioned, as well as other almost-desktop apps that could require more resources, esp. considering multi-tasking. And they would be on for long stretches of time, so even if the quad-core processor could cope, it would be nice if it could cope for twice as long. And then we have low-end devices. When the Palm came out, all the people who learned 68k assembly on their Amigas/Ataris were in demand again, as there was little CPU and memory to spare. On the other hand currently the environment mostly targeted at those sectors is the one with the least support/demand for native: FirefoxOS. Which seems a bit weird at first, as they certainly could make use of every MIPS they can scrounge. But that's economics for you: If it's mostly cheap phones and (most likely) users with little income to spare on frivolous apps, why would you target it? On the other hand, you're probably writing a webapp for other devices, and FirefoxOS users can piggyback on that. Sometimes you rather have a slow app than none at all.

EdSharkey 13y ago

All the pain of HTML5 and dealing with legacy and inconsistent browser implementations and yes, even poor performance in JavaScript, is worth it because of the deployment model. Writing videogames in HTML5 on mobile is a tall order. I think it's more important as an industry that we reckon with how to effectively manage large teams developing huge applications in JS/HTML/CSS. I suppose that Facebook's development suffered from too many cooks in the kitchen, cruft building up, race conditions, etc. A video series I've seen tries to tackle scaling up JavaScript development by organizing development from an Agile/TDD angle, and I think with some success: http://www.letscodejavascript.com/ http://www.letscodejavascript.com/

Pxtl 13y ago

Nicely explains why I find Android's use of Java as the lingua franca utterly perplexing. GC has no place on a low-power interactive platform.

Apocryphon 13y ago
Maybe it's a trade-off to make developer adoption easy.
- sjmulder 13y ago
  I’m not sure what alternatives they had. Of the top 10 languages on GitHub (https://github.com/languages https://github.com/languages), only C and C++ do not have garbage collection. Those are quite a different beast from Java of Objective-C. There’s a selection bias here but I struggle to come up with a popular non-GC, compiled language that operates on the same sort of level as Java or Objective-C.
  - Aqwis 13y ago
    Python's GC can be turned off.
    - Pxtl 13y ago
      Isn't python's GC reference-counted and deterministic anyways?
  - Roboprog 13y ago
    How about Pascal/Modula or FreePascal? It's almost as easy as Java (certainly less error prone as C), and almost as fast as C. Alas, I went to college in a time when they still taught Pascal, but then phased it out for C, which was more widely available on multiple platforms by the late 80s.
- eonil 13y ago
  Actually exactly opposite happen on game developers.

azakai 13y ago

Well written article, but I have a few comments: 1. This is about JS speed. How important is JS speed in mobile apps, compared to rendering for example? That's the crucial question here, and I don't see any numbers on it. Rendering, after all, should be the same speed as a native app. 2. "Nothing terribly important has happened to CPU-bound JavaScript lately" - picking some benchmarks where there has been little change is possible. There are also benchmarks where there have been large changes. For example, many browsers now have incremental GC and background thread JITing. In some workloads these make a huge difference - but perhaps not on the old SunSpider benchmark. edit: As an example of a type of code that can run far faster today than before, see Box2D, which is a realistic codebase since many mobile games use it: http://j15r.com/blog/2013/07/05/Box2d_Addendum http://j15r.com/blog/2013/07/05/Box2d_Addendum

ryanpetrich 13y ago
Canvas is only marginally slower than the native 2D drawing APIs (it is a thin wrapper for Skia on Android and CoreGraphics on iOS), but it still uses only a single CPU thread for drawing on both platforms. To use the GPU, one has to turn to the -webkit-transform CSS property which, under certain circumstances, promotes the element to a GPU buffer. Only once WebGL becomes accessible will the mobile web have a drawing API that is more efficient than the standard windowing APIs.

amenod 13y ago

Coming from the world of C / Java / PHP / Python and similar I found ObjectiveC maddening at times. But ARC really shines. Brilliant idea and well executed too: virtually no work on programming side (well, a few small caveats about function names apply) and no performance penalty on user side. Win-win. Good job Apple.

RyanZAG 13y ago

Big part of the article focuses on garbage collection, low ram environments, and mobile devices. I'd just like to say that my S4 has 2GB of ram (yes, 2GB). More than likely, my next phone will have 3GB or 4GB of ram. As the author mentions, once you get to 3x-6x more physical ram than what you absolutely need, the garbage collector no longer slows down your device - in fact, it speeds it up. So I'm not sure that this is really that big a problem. RAM is one of the areas where mobile devices really are improving rapidly (the other being 3D). That said, the article was excellent. Props to the author.

outworlder 13y ago
Yes. However, an iOS device feels consistently faster while using much less memory (and processor cores!) The extra hardware eats the battery like crazy. This is all anecdotal, but its my impression after switching from an iPhone 4 to a Nexus.
kogir 13y ago
Actually, in general as memory use increases GC takes more time, not less. It's rare that the number of objects stays constant and they just get bigger, and more objects means longer and more difficult tracing. HN has this problem. If we use more than a quarter or third of available RAM GC destroys site performance. Switching to faster RAM helps, but adding more doesn't.
- RyanZAG 13y ago
  Interesting point, but as per the chart[1] and discussion in the article, the relative memory footprint does have a big effect on performance. This is mostly felt when you get more complex object graphs. If the GC only needs to run once when you finish your calculation, it only needs to sweep once. If ram is limited and the GC is forced to run 100 times, then it must sweep 100 times. This is a lot of extra work and is the main reason why GC can be slow. In the case of HN, it sounds like you have more than enough RAM already, so you are not hitting the 'worse case' of GC that gets hit often in javascript on last generation mobile phones. The symptoms to the user are very similar to 'disk cache thrashing' and can be as bad as multiple second pauses. You're very correct in that increasing heap size too far is also a big problem, as running GC on 64GB of ram can take seconds - freezing up everything else while it runs. There are a number of guides on tuning the JVM on servers to avoid this. The new JVM GC algorithms are also very good at this situation by default, imo. Finally, on the issue of RAM speed: phones generally have a fixed amount of space dedicated to RAM - the 2GB chip on my S4 is the same as a 512MB chip on an older iPhone. This generally means that it is just as fast to access the 2GB of ram on an S4 compared to the 512MB on older devices. So at least on mobile, RAM speed is fairly closely related to RAM performance. I can't seem to find the benchmarks I saw earlier on this at present, anyone can confirm or deny with numbers? [1] http://sealedabstract.com/wp-content/uploads/2013/05/Screen-Shot-2013-05-14-at-10.15.29-PM.png http://sealedabstract.com/wp-content/uploads/2013/05/Screen-...

Joeri 13y ago

It's a well-researched article, but i doubt it will change anyone's mind. What i got as a take-away from this is that the sort of mobile apps that i work on can be done perfectly fine in javascript, because i did their desktop equivalents in ie7 on pc's with 512 mb ram. I'm reminded of the native vs web debates on the desktop. Everything the desktop guys said was true, with whole categories of apps essentially off-limits to web developers, and the remainder clearly and obviously inferior to their native counterparts. That didn't change, native apps still rule supreme in capability and usability. And yet the average person is using web apps the majority of the time (although that opinion admittedly depends on what you understand as average). The reason why that is translates to mobile. Everything this article says is true, and still mobile apps will be mostly web-based. There is no conflict between those facts.

martingordon 13y ago
Not sure if you know this, but iOS doesn't use a swap/page file. iOS will kill an app that uses a lot of memory because it values speed over stability and can very easily run out of RAM. In contrast, Windows won't kill an app when the system runs low of memory and will create more memory (however much slower that memory is than physical RAM) for the app to consume.
coldtea 13y ago
>That didn't change, native apps still rule supreme in capability and usability. And yet the average person is using web apps the majority of the time Those web apps most people use are trivial compared to the stuff we do on Desktop and Mobile. And the main reason people use them "the majority of time" is because they are huge time-sinks. E.g: Social apps like FB and Twitter, that translate to posting and reading text and images. Web mail, which translates to working with lists of text articles. Nothing much CPU intensive, in the way desktop/mobile apps are. As for the CPU intensive stuff, it's really still a novelty on the web. Nobody (== few people, less than 1% is the numbers I show), use Google Docs (and that's not even a full featured office suite anyway -- not to mention the spreadsheet for example takes lot of time even on my 2010 iMac/Chrome to apply stuff like conditional formatting). Even less people use something like online image editors and such. The only thing people really use on the web, and is CPU intensive are web games. And even those are more like 1995 quality desktop games.

baddox 13y ago

> BUT I THOUGHT V8 / MODERN JS HAD NEAR-C PERFORMANCE? > It depends on what you mean by “near”. If your C program executes in 10ms, then a 50ms JavaScript program would be “near-C” speed. If your C program executes in 10 seconds, a 50-second JavaScript program, for most ordinary people would probably not be near-C speed. I would actually reverse those two examples. A 10 second to 50 second jump probably wouldn't affect most user-facing programs that much, since it's either being done in the background or the user is staring at a progress bar. The UI of the application is probably (hopefully) already designed around the fact that there is a long-running process. But a 10ms to 50ms increase can be a big deal, since it's probably something that is intended to appear "instant" to the user.

MarkMc 13y ago

As an old Java programmer, I'm astounded that Apple are deprecating garbage collection on OS X. Is ARC really a better approach on the desktop?

drewcrawford 13y ago
No. But Apple has a shockingly small number of employees relative to other big software names, and they have had historically had much fewer third-party developers than other platforms. As a result, they have chosen to consolidate the mindshare onto one memory management technology rather than dilute the talent pool with two competing proposals. Given that iOS is much, much more popular than OS X, they have chosen to standardize on the technology that works best for the popular platform.
- Roboprog 13y ago
  I would respectfully have to disagree. I've been programming for about 30 years, but finally broke down and bought my first Mac about a year ago. It's a nice platform, and the native apps are a joy to use, compared to the sludge that most Windows apps are. Oh, and it lets me do most of what I have been doing on Linux the last 18 years. Not quite everything, but pretty close. No matter how much you tweak and tune a GC, there are still going to be times when it destroys "locality" in a hierarchical memory system and causes some kind of pause. For a small form entry program, this is probably negligible. As the size of the program and/or its data grows, or the time constraints grow tighter, these pauses will become more and more unacceptable. Most of my work the last 10 years has been in Java, but the JVM is not the one true path to enlightenment. TMTOWTDI :-)
pohl 13y ago
Yes, insofar as their desktop operating system is also their laptop operating system. A prominent theme at WWDC this year was all of the changes they've been doing to improve power management. That garbage collection thread always running in the background is going to interfere with your efforts to save battery. A predictable strategy based on automatic reference counting, on the other hand...
13y ago

weland 13y ago

This is actually a very interesting post, and the first one of this level of documentation I've seen in a while. I also actually agree with most of the author's points. That being said, I think there's a big elephant in the room: the additional layers of complexity. Much of the younger generation in the web development community seems very far removed from the principles of computer engineering, to the point that there's a bunch of things you can hint at simply by common sense, yet they are opaque to them. For instance: 1. Performance hits aren't only due to slower "raw" data processing, they can also occur due to data representation -- think about cache hits, for instance. Your average mobile application's processing is more IO-bound than processor-bound. Unless you can guarantee that your data is being efficiently represented, you get a hit from that. 2. Since the applications are sandboxed, the amount of memory your runtime occupies is directly subtracted from the amount of memory your application gets. The more layers your runtime piles up that cannot be shared between applications -- the more memory you consume without actually offering any functionality. 3. Every additional layer needs some processing time. Writing into a buffer that gets efficiently transfered into video memory is always going to be slower than JIT-ing instructions that write something into a buffer that gets efficiently transfered into video memory -- at the very least the first time around. I'm not sure if someone is actually trying to say or (futilely) prove that a web application is going to be as fast as a native one (assuming, of course, the native environment is worth a fsck) -- that's something people would be able to predict easily. This isn't rocket science, as long as you leave the jQuery ivory tower every once in a while. The question of whether it's fast enough, on the other hand, is different, but I think it's eschewing the wider picture of where "fast" is in the "efficiency" forest. I honestly consider web applications that don't actually depend on widely, remotely accessible data for their function to be an inferior technical solution; a music player that is written as a web application but doesn't stream data from the Internet and doesn't even issue a single HTTP request to a remote server is, IMO, a badly engineered system, due to the additional technical complexity it involves (even if some of it is hidden). That being said, if I had to write a mobile application that should work on more than one platform (or if that platform were Android...), I'd do it as a web application for other reasons: 1. The fragmentation of mobile platforms is incredible. One can barely handle the fragmentation of the Android platform alone, where at least all you need to do is design a handful of UI versions of your app. Due to the closed nature of most of the mobile platforms, web applications are really the only (if inferior, shaggy and poorly-performing) way to write (mostly) portable applications instead of as many applications as platforms. 2. Some of the platforms are themselves economically untractable for smaller teams. Android is a prime example of that; even if we skip over the overengineering of the native API, the documentation is simply useless. The odds of having a hundred monkeys produce something on the same level of coherence and legibility as the Android API documentation by typing random letters on a hundred keyboards are so high, Google should consider hiring their local zoo for tech writing consultance. When you have deadlines to meet and limited funding to use (read: you're outside your parents' basement) for a mobile project, you can't always afford that kind of stuff. Technically superior, even when measurable in performance, isn't always "superior" in the real life. Sure, the fact that a programming environment with bare debugging capabilities, almost no profiling and static analysis capabilities to speak of and limited optimization options at best is the best you can get for mobile applications is sad, but I do hope it's just the difficult beginning of an otherwise productive application platform. I also don't think the fight is ever going to be resolved. Practical experience shows users' performance demands are endless: we're nearly thirty years from the first Macintosh, and yet modern computers boot slower and applications load slower than they did then. If thirty years haven't filled the users' thirst for good looks and performance, chances are another thirty years won't, either, so thirty years from now we'll still have people frustrated that web applications (or whatever cancerous growth we'll have then) aren't fast enough. Edit: there's also another point that I wanted to make, but I forgot about it while ranting the things above. It's related to this: > Whether or not this works out kind of hinges on your faith in Moore’s Law in the face of trying to power a chip on a 3-ounce battery. I am not a hardware engineer, but I once worked for a major semiconductor company, and the people there tell me that these days performance is mostly a function of your process (e.g., the thing they measure in “nanometers”). The iPhone 5′s impressive performance is due in no small part to a process shrink from 45nm to 32nm — a reduction of about a third. But to do it again, Apple would have to shrink to a 22nm process. The point the author is trying to make is valid IMHO -- Intel's processors do benefit from having a superior fabrication technology, but just like in the case above, "raw" performance is really just one of the trees in the "performance" view. First off, a really advanced, difficult manufacturing process isn't nice when you want massive production. ARM isn't even on 28 nm yet, which means that the production lines are cheaper; the process is also more reliable, and being able to keep the same manufacturing line in production for a longer time also means the whole thing costs less on a long term. It also works better when you have an economic model like ARM's -- you license your chips, rather than producing them. When you have a bunch of vendors competing for the same implementation of a standard, with many of them being able to afford the production tools they need, chances are you're going to see lower cost just from the competition effect. There's also the matter of power consumption, which isn't negligible at all, especially due to batteries being such nasty, difficult beasts (unfortunately, we suck at storing electrical energy). Overall, I think that within a year or two, once the amount of money shoved into mobile systems will reach its peak, we'll see a fairly slower rate of performance improvement on mobile platforms, at least in terms of raw processing power. Improvements will start coming from other areas.

williamcotton 13y ago

While I feel that most of the article is little more than reaching for straws, he does make some good points about memory management in Javascript and on mobile. Garbage collectors should be optional. I would really love to be able to handle my memory directly if possible, and while there are some things I can do related to object pooling, I lose control over that with closures and a more functional approach. I guess to counter my own argument here I will say that for most resource intensive things like simulations (call them games if you will), an object-oriented approach does a better job of modeling than a functional one. Game loops, sprites, bullets flying around... go OOP... and then use an object pool and limit your use of closures. Is it a pain in the ass? You bet, but so is having to manage the heap on your own. Now, as for the rest of the article, the author did a LOT to discredit himself insisting that JS performance will not increase over the next few years... dude, come on, winning isn't as important as learning and discussing, and you're clearly just trying to WIN an argument. This article is not very balanced. It is basically just saying that all software written for a VM is stupid. That the concept of Garbage Collection is an abomination. The truth is that VMs are incredibly successful and aren't going anywhere. I mean, look at the rise of VPS! Now compiled C and even machine code aren't running as fast as they could be! Run for the hills! Performance is not the be-all, end-all of computing. We're a social species and the reason that JS is the so successful has more to do with the fact that it is hosted in a VM based on open standards than anything else. So why have we moved to virtualization? Because it makes a LOT of sense. It's the same reason we invented compilers and higher-order languages in the first place... we're human. We are the ones writing and reading source code... the machines don't, they just blindly follow instructions. We choose to sacrifice speed for a more humanistic interaction with our machines, and that applies just as much to programmers as to the people who just use programs. These are very early days for mobile computing. You say you want to raise the level of discourse? Well then do it by writing articles that are more about discussing solutions than winning. For example, HTML5rocks.com (and yes, I am fully aware of the HTML5 marketing machine..) has been writing some good articles on memory management in Javascript, and that approach actually raises the level of discourse.

eropple 13y ago
I'm not sure how closely you actually read his post because he doesn't say anything you attribute to him about software written for VMs being stupid--in fact he explicitly states that it makes a lot of sense in desktop environments because it improves programmer productivity. He's got a heading, in all caps, saying "GC ON MOBILE IS NOT THE SAME ANIMAL AS GC ON THE DESKTOP", and he quotes, while indicating agreement with, guys like Herb Sutter and Miguel de Icaza explicitly stating that managed languages make tradeoffs for developer productivity. Which they do, and those tradeoffs don't really work on mobile (and won't until we see significantly improved memory density, among other things). Disagree with him if you want to--I'd like to, because I like the JVM and the CLR, but he has the weight of evidence on his side--but can we not make stuff up?

MatthewPhillips 13y ago

This article is weird. It starts off with a strong premise -- we need more fact-based arguments when discussing technology choices. Yes, agree! There are a fair amount of good points here, particularly about ARM's potential but he's very dismissive of counter points and seems to believe having lots of quotes is a substitute to a good argument. The section about garbage collection is especially unconvincing and, again, dismissive of counter points. He never really addresses Android or Windows Phone (which, by the way, he repeatedly mistakenly calls Windows Mobile -- which is right in line with the extreme iOS focus the article has). He mentions them, but then seems to think that a few quotes that show that, under some extreme circumstances -- mostly games -- the GC can be a problem on those platforms. But which is it, are all Java and C# Android/Windows Phone apps unacceptably slow or are some types of apps not really doable in those GC languages? This is important because a large part of his argument centers on GCs not working on mobile. I'd conclude that the article is overly defensive. To the point that the author repeatedly poisons-the-well of anyone who might potentially disagree. > we need to have conversations that at least appear to have a plausible basis in facts of some kind–benchmarks, journals, quotes from compiler authors, whatever. This is where I think the article falls apart. Appearing to be based on facts is what this article is about, but appearance just gets you talked about. It doesn't really move the conversation forward at all.

rsynnott 13y ago
> But which is it, are all Java and C# Android/Windows Phone apps unacceptably slow or are some types of apps not really doable in those GC languages? He didn't really say either; he pointed out (correctly) that for certain applications in a memory managed language, you'll want to essentially avoid using the GC, and you'll certainly have to be very cautious of it. The extreme case was old J2ME games, which usually worked by allocating all the memory they'd use as a large array at startup, and doing manual memory management thereafter. In general, you can do just about anything in a memory managed language, but in some cases, especially games, it may actually end up a lot more work than in a non-managed language.
- spullara 13y ago
  There are two performance choices in GC languages: 1) don't allocate after initialization 2) only allocate per small time frame There is an issue that 2) is only really feasible in server settings and doesn't really work for clients. I buy his argument even though I don't wish to program under his restrictions.

kannanvijayan 13y ago

Disclaimer: I'm a JS JIT developer. The use of Sunspider performance to talk about JS application performance is unfortunate, and undermines a significant part of the argument made in the article. Sunspider is a great benchmark to use to talk about web _page_ performance. This is how JITs work: 1. Javascript code starts executing in a slow environment. 2. In this execution mode, a lot of overhead is spent collecting type information so that the hot code can be optimized. 3. After some period of time, the hot code is compiled with an optimizing compiler, which is a very expensive task. 4. The compiled code starts running. For example, in Mozilla's JS engine, these are the actual numbers associated with optimization: 1. A function starts off running in the interpreter 2. After it gets called 10 times (or a loop within it goes around 10 times), it gets compiled with the Baseline JIT, which performs heavyweight bytecode analysis on the javascript code, generates unoptimized machine code which is instrumented to acquire information about the executing JS. 3. After 1000 iterations (most of that running within Baseline jitcode), the function gets compiled with our optimizing compiler, IonMonkey. How does this relate to Sunspider? Well, if you actually run Sunspider, you'll notice that the entire benchmark takes about 0.2 seconds or less on a modern machine (about 1.5 seconds on a modern phone). It's an extremely tiny benchmark (in terms of computation heaviness). Comparatively, the Octane suite, while containing fewer benchmarks, actually takes 100 times or so longer to execute than sunspider. How many apps do you use that run for less than 1.5 seconds? This is the problem with using Sunspider to talk about app performance. Sunspider doesn't measure JIT performance very well at all. When JIT engines execute Sunspider, they spend a relatively large amount of that time just collecting the necessary information before they can start optimizing. Then, soon after we spend all that effort optimizing the code, the benchmark ends, without really taking advantage of all that fast code. Very often, JIT optimizations that speed up computationally heavy benchmarks actually regress Sunspider. This is because the optimizations add some extra weight to the initial analysis that happens before optimized code is generated. This hurts sunspider because the initial analysis section is much more heavily weighted than later optimized performance. Sunspider's runtime characteristics make it a good benchmark for measuring web PAGE performance. Web pages are much more likely to contain code that executes for short periods of time (a few ms), and then stops. But apps have much different runtime characteristics. Apps don't execute code for a few milliseconds and then stop. They run for dozens of seconds, minimally, and often minutes at a time. A JIT engine has much more opportunity to generate good optimized code, and have that optimized code taken advantage of over more of the execution time. It's unfortunate that such a fundamental misunderstanding of the characteristics and nature of optimized javascript is used to drive an argument about it.

fpgeek 13y ago

I think the author is making a big mistake in selling short the possibility of x86-class CPU performance on mobile. Perhaps it comes from his iOS focus, but he's just wrong about the difficulty of transitioning the mobile software ecosystem to x86. Android is there today and has been for over a year (as the reviews of last year's x86 smartphones make abundantly clear). And, as we all know, Android is the majority of the devices, by a large margin. It is true that iOS, Windows Phone and other platforms may have more trouble with an x86 transition, but so what? If Android makes a performance leap by moving to x86, other platforms will either find a way to keep up or they'll fall behind in the market. Either way, the mobile center-of-gravity will move towards x86-class CPU performance.

alayne 13y ago
Motorola's Atom based RAZR was slower than their ARM based one. The x86 architecture isn't doing anything for you on mobile and so far the reason Intel has struggled is because they couldn't compete on power consumption, a more important factor. Since desktops can burn power, they can run a lot more transistors and run them more quickly. I don't see mobile CPU performance catching up to desktops soon.
- fpgeek 13y ago
  Here's a specific comparison of the Razr i vs the Razr M. http://www.engadget.com/2012/10/04/motorola-razr-i-review/ http://www.engadget.com/2012/10/04/motorola-razr-i-review/ Yes, the Razr i lost (mostly modestly) on 4 out of 5 performance benchmarks, but... 1. It modestly won on power consumption (9 hours vs 8). 2. Quoting from the review: "Aside from the benchmark results outlined above, the Medfield entry offered a marginally faster response to most actions." 3. Drawing CPU vs CPU conclusions from several benchmarks is complicated by one of the other differences between the two phones - the GPU (which is mostly an orthogonal question). Oh, and then there's that benchmark the RAZR i won, by almost a factor of 2: SunSpider. While SunSpider has its limitations, it's the most still relevant benchmark of the set to the discussion we're having right now. And this performance difference has real-world consequences (another quote): "The results remain largely unchanged, but after spending a week with the device, we'd like to add that the web browser still gives a superb performance." Intel's problem in mobile has never been performance (except when self-inflicted and they're past that). As of last year, it isn't power consumption either. Today, Intel's last problem is modems (specifically LTE modems), and they're hard at work on that one too: http://newsroom.intel.com/community/intel_newsroom/blog/2013/06/04/intel-is-inside-the-new-samsung-galaxy-tab-3-101-inch http://newsroom.intel.com/community/intel_newsroom/blog/2013... Finally, Intel's tagline for Silvermont is "~3X the Performance or ~5X Lower Power". If they pull that off and integrate it with a competitive LTE modem (and those are both still significant ifs even though today's indications look good), that's a ~2X SunSpider combined with a separate ~3X CPU leap. That won't just multiply because the bottlenecks will shift and SunSpider is the wrong benchmark CPU-bound JavaScript anyway. But however it plays out, that still would close a big chunk of the mobile-desktop JavaScript performance gap, especially when you notice that this year's Haswell focused on power consumption and, at best, only offers a small performance bump over last year's Ivy Bridge. It isn't a lock, but it isn't a possibility to dismiss either.

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6ren 13y ago

Why not increase RAM x5?

chris_mahan 13y ago
RAM has to be powered.
- 6ren 13y ago
  I hadn't considered power, thinking it would be minimal. Research agrees - but task dependent: The RAM, audio and ﬂash subsystems consistently showed the lowest power consumption. ...RAM power can exceed CPU power in certain workloads, but in practical situations, CPU power overshadows RAM by a factor of two or more. [p.11, graph on p.5] from 2010: An Analysis of Power Consumption in a Smartphone https://docs.google.com/viewer?url=https%3A%2F%2Fwww.usenix.org%2Fevent%2Fusenix10%2Ftech%2Ffull_papers%2FCarroll.pdf https://docs.google.com/viewer?url=https%3A%2F%2Fwww.usenix....

6ren 13y ago

Aside: in some circumstances, JIT can be faster than compiled, by recompiling based on run-time usage, and so choosing optimizations appropriate to execution flow.

6ren 13y ago

Why don't gc languages have optional memory management - include free(), so there's less work for the gc?

lalc 13y ago
Do you know what GC does?
eonil 13y ago
Maybe Microsoft C++/CLI?
rsynnott 13y ago
That would tend to make the GC more complicated, not less. Some memory managed VMs do allow you to allocate outside the GC'd heap, though; see java.nio.ByteBuffer in Java (or sun.misc.unsafe, if you're very daring)

modeless 13y ago

The use of SunSpider to argue that CPU-bound JavaScript performance has not improved since 2010 is simply wrong. What SunSpider does is not at all representative of what CPU-bound JavaScript in a modern web app does. V8 and SpiderMonkey have significantly improved performance on real app code since 2010, despite the unchanged SunSpider scores. I say this as a developer on a large and heavily CPU-bound JavaScript app. The dismissal of asm.js is wrong too, for many reasons. Browsers don't need to support it explicitly necessarily. GC pauses are eliminated regardless of browser support, and most JavaScript optimizations will help asm.js too. The elimination of GC is not the only benefit, or even the main one really (the main benefit is the elimination of polymorphism, improving JIT performance and allowing AOT compilation). The assertion that it's not "really" JavaScript is irrelevant to the question of whether it can speed up web apps or not. All that said, I really appreciate the article and the discussion it's sparked.

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lnanek2 13y ago

Some of these comments are very out of date. Android hasn't had a stop the world garbage collector that caused 200-300ms delays since before Android 2.3. It's true I had to avoid dereferencing anything in the game loop back before then, but I don't know anyone who codes like that anymore on Android and I know hundreds of developers...

deleted 13y ago
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epochwolf 13y ago
And most android devices are on what version of android?
- Jare 13y ago
  2.3 and above, according to Unity's hardware stats at http://stats.unity3d.com/mobile/index.html http://stats.unity3d.com/mobile/index.html

tedsanders 13y ago

Off-topic nitpick: I believe this sentence is untrue: "And Intel had to invent a whole new kind of transistor since the ordinary kind doesn’t work at 22nm scale." First, regular transistors do work at the 22nm scale (but tri-gate/finfet transistors work better, if you can pattern them reliably). Also, Intel didn't invent the tri-gate/finfet transistor. They just got it to production first.

erhardm 13y ago
To be fair, he said he's not a hardware guy. But he also is right, FinFet transistors are better for power consumption and that's really important in mobile devices

bitcuration 13y ago

Wish author has explained why Flipboard which is built in html5/javascript is not awfully slow like linkedin.

eonil 13y ago
Any clue that it's actually been implemented with HTML5/JS?

aconz2 13y ago

over 180 network requests and over 40 scripts, maybe the author needs to learn a bit more about best practices on the web before standing on his soapbox. and quit bolding things mid-sentence.

cromwellian 13y ago

I generally agree with his comments on JS and memory management, for stuff like games, or image processing, but IMHO, these are not, in general, the reason why people have this notion that "mobile web apps are slow". There aren't a lot of games or Instagram apps written in JS, what there are, are lots of content oriented and form processing based mobile web sites, like your Bank, or your insurance company, or Slate or HuffingtonPost, and it is these sites which are prompting you to download native versions, and it is people's experience of these lightweight (non-CPU dependent) sites as being slow which I think needs addressing. I would break it down into three effects: 1) startup latency 2) excessive repaints/not leveraging compositor/jank 3) 'uncanny valley' issues where web emulations of native widgets don't match 100% with the feel of system widgets. The basic documented-oriented part of the mobile web is a lot slower than something like UIKit/TextKit in iOS, so the time to launch even a basic form to display some data, or a few paragraphs, and smoothly scroll it, with all rendering effects, and without layout or repaint jank, is just more work on the mobile web to optimize for, and therefore, many developers don't do it, or aren't aware of how to do it, leading to enduser perception that "mobile web is slow" I'd summarize my point of view as: NaCl/PNaCL won't solve our problems (although it is still a good idea to do them)

ashcairo 13y ago

Great post! I'm a huge C++/Anti-GC/Games developer here. Few notes. On performance, most of the time, I'm GPU bound when writing games. In this JavaScript based game for iOS: http://imgur.com/XQdGKHw,swTBC9T#0 http://imgur.com/XQdGKHw,swTBC9T#0 I'm getting 11ms used up on the CPU and 29ms used up on the GPU: http://imgur.com/XQdGKHw,swTBC9T#1 http://imgur.com/XQdGKHw,swTBC9T#1 That's 11ms using iOS JavaScript which isn't JIT optimised. Granted CPU will go crazy if I try running advanced Physics using JavaScript, but I tend to push Math intensive functions to C++ using a hybrid approach. On GC, I'm not a fan, I like managing my memory. However, UnrealEngine, which is super-awesome, has a built in garbage collector. In my experience with it, whenever someone tries to blame its GC for performance/memory abuse, to my dissatisfaction, the problem usually lies elsewhere. Main reason I've full on switched to the JavaScript world for development is its ability to re-interpret code on the fly. Allowing me to write and tweak, code/ui/design changes in real-time across multiple-devices.

coldtea 13y ago

I have to say, any minor quibbles aside, this is the best modern-day, non-academic article I've read on HN since forever.

gwu78 13y ago

Has anyone in mobile OS and mobile apps ever questioned the assumptions that Java must be used and/or a scripting language must be used, e.g., Javascript? What if we had a mobile OS and a mobile app that was 100% Java free and only ran compiled code (i.e., that compiles to ARM assembly)? Under the Steve Jobs theory of computers, everything should be "fast enough" just as it is. Because Moore's law and the increasing computing power of hardware should allow us to focus entirely on making everything as user friendly (including develeoper friendly) as possible without having regard for software efficiency. Watch for example the 1980 documentary "Entrepreneur" to see Jobs state this while the cameras follow him around during a NeXT retreat in Pebble Beach. But I've also seen Hertzfeld say Jobs for example pushed hard for him to try to reduce boot times on the Mac. This is of course is firmly in the realm of software (bootloader and kernel) so it would seem a conflict of ideas. Software efficiency does matter sometimes. Even when the focus is user friendliness and user experience. Jobs also said things back in the day about "the line between hardware and software" becoming blurred. I find this difficut to agree with. But then I'm not called a genius like he was. There are no doubt competent C and ARM assembly programmers out there. I've seen them doing embedded work and making games. Alas, I do not think they are by and large involved with working on the popular mobile OS's. Instead the focus seems to be on people who prefer to work with virtual machines and scripting languages.

Moto7451 13y ago
Has anyone in mobile OS and mobile apps ever questioned the assumptions that Java must be used and/or a scripting language must be used, e.g., Javascript? What if we had a mobile OS and a mobile app that was 100% Java free and only ran compiled code (i.e., that compiles to ARM assembly)? First, it's a bit pedantic but JIT VMs still compile down to ARM assembly on an ARM device. They basically optimize away the overhead of interpreting their target language. That said, what you're getting at is how Palm and Windows Mobile did it (for the most part, there is/was .Net for Windows CE) and how iOS does it now. Ubuntu Mobile and Win Phone 8 offer native toolsets in addition to GC/managed runtimes. I don't think its an assumption at all that mobile devices have to use Java. J2ME didn't exactly take over the world, and that had the advantage of hardware acceleration in the form of ARM Jazelle[1]. What has happened is as hardware gets faster/cheaper, Java, .Net, JS, etc become a better fit for development on mobile devices. On the Desktop we have stupidly powerful machines that can generally brute force their way through the inherent overhead of interpreted/JITed/VMed languages. On mobile however, we're not there yet. [1]http://en.wikipedia.org/wiki/Jazelle http://en.wikipedia.org/wiki/Jazelle

andrewgleave 13y ago

Anyone interested in optimising their mobile web applications should watch Apple's Safari tracks from this year's WWDC. They have plenty of informative advice on how to improve general performance and how to use tools WebKit provides to measure performance problems. Some key take aways: Avoid using libraries (like jQuery). It will reduce memory consumption significantly. Be careful how often you're invalidating style info and forcing recomuptation Avoid using scroll handlers to do layout (especially when you're likely to inadvertently invalidate styles at the same time)

glogla 13y ago

I like how he says that "mobile web apps are slow and always will be" (not a direct quote), but then dismisses asm.js as "it woudn't be a JavaScript anymore" so it doesn't count. The point of asm.js (if I understand it correctly) is that you can use JavaScript in way similar to Python -- you can make your application in high-level language, and then, after profiling, rewrite the performance critical parts into lower-level, less powerful, but faster language. That means, it still is "web app" but it can perform reasonably.

Roboprog 13y ago

I really liked this article: I think he was very methodical in challenging current dogma that GC/VM operations can be made as fast or faster than slightly lower level approaches. For the curious, I have a simple benchmark program that focuses on string manipulation (and deliberately creates many temp string objects, like a real app would) in various languages. If anybody wants to download and try it on the latest version of their favorite languages on the host-de-jure, go for it! https://github.com/roboprog/mp_bench https://github.com/roboprog/mp_bench