6 ms·

Who knows how fast Emscripten+asm.js-compiled DartVM would be compared to Dart2JS in 2013? I don't know yet, and apparently neither do you. JITs can be tricky,

Who knows how fast Emscripten+asm.js-compiled DartVM would be compared to Dart2JS in 2013? I don't know yet, and apparently neither do you. JITs can be tricky, but @azakai is having good results with Emscripten+asm.js'ed LuaJIT2. What I wrote 593+ days ago was about the Dash memo's Microsoft-like strategy. My point then was not that it couldn't ever be defeated by something like our work on asm.js and Emscripten. Never say never. My point rather was that the Dash strategy intentionally used Google's big resources to push a gratuitously non-standards-based agenda at the expense of its Web-standards-based efforts. Indeed, since then it has become clear that Google miscalculated. Dart even gave up bignums (the int type) to support Dart2JS/DartVM equivalence, which I think is a mistake. Bignums are actually on the JS standards-based agenda: http://wiki.ecmascript.org/doku.php?id=strawman:bignums http://wiki.ecmascript.org/doku.php?id=strawman:bignums http://wiki.ecmascript.org/doku.php?id=strawman:value_objects http://wiki.ecmascript.org/doku.php?id=strawman:value_object... See also https://bugzilla.mozilla.org/show_bug.cgi?id=749786 https://bugzilla.mozilla.org/show_bug.cgi?id=749786 Given all the time that has passed since 2010, Google champions in Ecma TC39 could easily have worked bignums into ES7 if not ES6. At a higher level, by over-investing in Dart and under-investing in JS (the V8 team was moved from Aarhus to Munich and with the no-remoties rule had to be rebuilt), Google has missed opportunities such as game-industry work we announced at GDC with Epic. This is "ok", it's their choice, but I still say that it is inherently much more fragmenting than any optimization of the asm.js kind, and that it under-serves the standards-based Web. Maybe in a few years we can evolve JS to incorporate whatever helps DartVM beat Dart2JS, if there's any gap left. However, the idea that mutable global objects in JS necessarily mean VM-snapshotting is impossible is simply false. On the other hand, do we really need VM snapshots to speed up gmail startup? LOL! /be

solomatov 13y ago
What about PNaCl? What's the reason you don't support it in Mozilla? It's based on open source tools, and can be easily integrated into any browser. P.P.S. IMO, the biggest problem about JavaScript isn't its performance. Performance is ok, and enough for the games, thanks to WebGL. The language, like many other dynamic languages, is just not very suitable for large scale development. People who write such applications, have to resort to using tools like GWT, which add substantial overhead (both in compilation time and performance). Does Mozilla has any plans to improve the situation here?
- BrendanEich 13y ago
  Your green-colored id says you are new here, and yet unwilling to do basic research in HN on the topic you ask about. I'll take this in the "Dear LazyWeb" spirit, assume that you are not trolling, and give some links. First, one of a few obvious searches: https://www.google.com/search?q=site:news.ycombinator.com+pnacl+mozilla+brendan https://www.google.com/search?q=site:news.ycombinator.com+pn... From the results, an entry point into a deep thread, posted by Maciej Stachowiak of Apple: https://news.ycombinator.com/item?id=4648045 https://news.ycombinator.com/item?id=4648045 Further in this sub-thread, I comment on the loaded language used to open-wash NaCl and portray critics of it as haters: https://news.ycombinator.com/item?id=4650689 https://news.ycombinator.com/item?id=4650689 Back to your comment: "It's based on open source tools" is true of Emscripten too. The bit about "can be easily integrated into any browser" is false due to Pepper, the large new target runtime for *NaCl. Pepper is a non-standard and unspecified-except-by-C++-source plugin API abstracting over both the OS and WebKit -- now Blink -- internals. To make such an airy assertion in an under-researched comment makes me suspect that you don't know that much about either PNaCl or "any browser". So why did you make that confident-sounding claim? These days, large apps are written in JS, even by hand. GWT is not growing much from what I can tell, compared to its salad days. Closure is used the most within Google, and Dart has yet to replace Google's use of GWT + Closure. Outside Google, hundreds of languages compile to JS (http://altjs.org/ http://altjs.org/). CoffeeScript is doing well still. TypeScript is Microsoft's answer to Dart, and more intentionally aligned with the evolving JS standard. "Does Mozilla has any plans to improve the situation here?" Have you heard of ES4? Mozillans including yours truly poured years into it, based on the belief that programming-in-the-large required features going back to "JS2" in 1999 (designed by Waldemar Horwat), such as classes with fixed fields and bound methods, packages, etc. Some of the particulars in ES4 didn't pan out (but could have been fixed with enough time and work). Others are very much like equivalent bits of Dart. One troublesome idea, namespaces (after Common Lisp symbol packages) could not be rescued. But ES4 failed, in part due to objections from Microsofties (one now at Mozilla) and Googlers. In a Microsoft Channel 9 interview with Lars Bak and Anders Hejlsberg, Lars and Anders both professed to like the direction of ES4 and wondered why it failed. _Quel_ irony! As always, Mozilla's plans to improve the situation involve building consensus on championed designs by one or two people, in the standards bodies, and prototyping as we specify. This is bearing fruit in ES6 and the rest of the "Harmony era" editions (ES7 is being strawman spec'ed too now; both versions have partial prototypes under way). Founding Harmony email (on the demise of ES4): https://mail.mozilla.org/pipermail/es-discuss/2008-August/006837.html https://mail.mozilla.org/pipermail/es-discuss/2008-August/00... A talk I gave last fall on ES6 and beyond. http://brendaneich.github.io/Strange-Loop-2012/#/ http://brendaneich.github.io/Strange-Loop-2012/#/ For programming in the large, ES6 offers modules, classes, let, const, maps, sets, weak-maps, and many smaller affordances. I hope this helps. Even more is possible, if only the browser vendors and others invested in JS choose to keep working on evolving the language.
mraleph 13y ago
You can't simply asm.js'fy LuaJIT2 because it has an interpreter hand written in assembly and it generates native code to achieve peak performance. You can only asm.js'fy a normal Lua interpreter which is up to 64x slower than LuaJIT on benchmarks, when compared natively. So asm.js'fied Lua will be up to 128x slower. Does not sound that impressive...
- BrendanEich 13y ago
  Hi -- you make a good point, the one seemingly at issue in this tangent (but not really the bone of contention). As noted, I don't know which will ultimately prevail in pure performance: DartVM or Dart2JS on evolved JS. In the near term, of course DartVM wins (and that investment made "against cross-browser standards" was the strategic bone of contention 594 days ago). I do know that in the foreseeable term, we browser vendors don't all have the ability to build two VMs (or three, to include Lua using LuaJIT2 or something as fast, in addition to JS and Dart; or more VMs since everyone wants Blub ;-). The cross-heap cycle collector required by two disjoint VMs sharing the DOM already felled attempts to push Dart support into WebKit over a year ago. Apple's Filip Pizlo said why here: https://lists.webkit.org/pipermail/webkit-dev/2011-December/018811.html https://lists.webkit.org/pipermail/webkit-dev/2011-December/... Other browser vendors than Apple may have the resources to do more, but no browser wants to take a performance hit "on spec". And Mozilla at least has more than enough work to do with relatively few resources (compared to Apple, Google, and Microsoft) on JS. As you've heard, asm.js was an easy addition, built on our JIT framework. So you're right, an optimizing JIT-compiling VM is not easily hosted via a cross-compiler, or emulated competitively by compiling to JS. LuaJIT2 would need a safe JIT API from the cross-compiler's target runtime, whether NaCl/PNaCl's runtime or Emscripten/asm.js's equivalent. Googling for "NaCl JIT" shows encouraging signs, although the first hit is from May 2011. The general idea of a safe JIT API can be applied to asm.js too. In any event, one would need to write a new back end for LuaJIT2. Bottom line: we're looking into efficient multi-language VM hosting via asm.js and future extensions, but this is obviously a longer road than C/C++ cross-compiling where we've had good early wins (e.g., Unreal Engine).
- azakai 13y ago
  > You can only asm.js'fy a normal Lua interpreter which is up to 64x slower than LuaJIT on benchmarks Yes, LuaJIT is fast, but even their own numbers are nowhere near 64x being the mean or median, http://luajit.org/performance_x86.html http://luajit.org/performance_x86.html Furthermore, these are microbenchmarks. Large codebases might paint a different picture. I am also not sure why LuaJIT is the most interesting comparison. Yes, LuaJIT is a work of art, but even normal Lua is quite fast, beating Python and Ruby easily. So even a half-speed Lua-VM-in-JS would be competitive with other dynamic languages - which means it is fast enough for many uses. Finally, we can certainly compile VMs that JIT, we just need to create JIT backends for them that emit JS (preferably asm.js). But LuaJIT is more tricky, as you note, because it lacks a portable C interpreter.
backspaces 13y ago
It is SOOO odd to see folks not "get" the JavaScript Everywhere revolution. Node, JS/CoffeeScript, JSON: Server, Client, Network Data. Complete stack, period. C++?? Gack, so yesterday. Python, Ruby, etc .. so without dynamic windows everywhere. Google?? So confused. What's their next project jerked out of our workflow? When is Google coming out of beta? Keep up the good work /be -- Owen

solomatov 13y ago

What about PNaCl? What's the reason you don't support it in Mozilla? It's based on open source tools, and can be easily integrated into any browser. P.P.S. IMO, the biggest problem about JavaScript isn't its performance. Performance is ok, and enough for the games, thanks to WebGL. The language, like many other dynamic languages, is just not very suitable for large scale development. People who write such applications, have to resort to using tools like GWT, which add substantial overhead (both in compilation time and performance). Does Mozilla has any plans to improve the situation here?

BrendanEich 13y ago
Your green-colored id says you are new here, and yet unwilling to do basic research in HN on the topic you ask about. I'll take this in the "Dear LazyWeb" spirit, assume that you are not trolling, and give some links. First, one of a few obvious searches: https://www.google.com/search?q=site:news.ycombinator.com+pnacl+mozilla+brendan https://www.google.com/search?q=site:news.ycombinator.com+pn... From the results, an entry point into a deep thread, posted by Maciej Stachowiak of Apple: https://news.ycombinator.com/item?id=4648045 https://news.ycombinator.com/item?id=4648045 Further in this sub-thread, I comment on the loaded language used to open-wash NaCl and portray critics of it as haters: https://news.ycombinator.com/item?id=4650689 https://news.ycombinator.com/item?id=4650689 Back to your comment: "It's based on open source tools" is true of Emscripten too. The bit about "can be easily integrated into any browser" is false due to Pepper, the large new target runtime for *NaCl. Pepper is a non-standard and unspecified-except-by-C++-source plugin API abstracting over both the OS and WebKit -- now Blink -- internals. To make such an airy assertion in an under-researched comment makes me suspect that you don't know that much about either PNaCl or "any browser". So why did you make that confident-sounding claim? These days, large apps are written in JS, even by hand. GWT is not growing much from what I can tell, compared to its salad days. Closure is used the most within Google, and Dart has yet to replace Google's use of GWT + Closure. Outside Google, hundreds of languages compile to JS (http://altjs.org/ http://altjs.org/). CoffeeScript is doing well still. TypeScript is Microsoft's answer to Dart, and more intentionally aligned with the evolving JS standard. "Does Mozilla has any plans to improve the situation here?" Have you heard of ES4? Mozillans including yours truly poured years into it, based on the belief that programming-in-the-large required features going back to "JS2" in 1999 (designed by Waldemar Horwat), such as classes with fixed fields and bound methods, packages, etc. Some of the particulars in ES4 didn't pan out (but could have been fixed with enough time and work). Others are very much like equivalent bits of Dart. One troublesome idea, namespaces (after Common Lisp symbol packages) could not be rescued. But ES4 failed, in part due to objections from Microsofties (one now at Mozilla) and Googlers. In a Microsoft Channel 9 interview with Lars Bak and Anders Hejlsberg, Lars and Anders both professed to like the direction of ES4 and wondered why it failed. _Quel_ irony! As always, Mozilla's plans to improve the situation involve building consensus on championed designs by one or two people, in the standards bodies, and prototyping as we specify. This is bearing fruit in ES6 and the rest of the "Harmony era" editions (ES7 is being strawman spec'ed too now; both versions have partial prototypes under way). Founding Harmony email (on the demise of ES4): https://mail.mozilla.org/pipermail/es-discuss/2008-August/006837.html https://mail.mozilla.org/pipermail/es-discuss/2008-August/00... A talk I gave last fall on ES6 and beyond. http://brendaneich.github.io/Strange-Loop-2012/#/ http://brendaneich.github.io/Strange-Loop-2012/#/ For programming in the large, ES6 offers modules, classes, let, const, maps, sets, weak-maps, and many smaller affordances. I hope this helps. Even more is possible, if only the browser vendors and others invested in JS choose to keep working on evolving the language.

mraleph 13y ago

You can't simply asm.js'fy LuaJIT2 because it has an interpreter hand written in assembly and it generates native code to achieve peak performance. You can only asm.js'fy a normal Lua interpreter which is up to 64x slower than LuaJIT on benchmarks, when compared natively. So asm.js'fied Lua will be up to 128x slower. Does not sound that impressive...

BrendanEich 13y ago
Hi -- you make a good point, the one seemingly at issue in this tangent (but not really the bone of contention). As noted, I don't know which will ultimately prevail in pure performance: DartVM or Dart2JS on evolved JS. In the near term, of course DartVM wins (and that investment made "against cross-browser standards" was the strategic bone of contention 594 days ago). I do know that in the foreseeable term, we browser vendors don't all have the ability to build two VMs (or three, to include Lua using LuaJIT2 or something as fast, in addition to JS and Dart; or more VMs since everyone wants Blub ;-). The cross-heap cycle collector required by two disjoint VMs sharing the DOM already felled attempts to push Dart support into WebKit over a year ago. Apple's Filip Pizlo said why here: https://lists.webkit.org/pipermail/webkit-dev/2011-December/018811.html https://lists.webkit.org/pipermail/webkit-dev/2011-December/... Other browser vendors than Apple may have the resources to do more, but no browser wants to take a performance hit "on spec". And Mozilla at least has more than enough work to do with relatively few resources (compared to Apple, Google, and Microsoft) on JS. As you've heard, asm.js was an easy addition, built on our JIT framework. So you're right, an optimizing JIT-compiling VM is not easily hosted via a cross-compiler, or emulated competitively by compiling to JS. LuaJIT2 would need a safe JIT API from the cross-compiler's target runtime, whether NaCl/PNaCl's runtime or Emscripten/asm.js's equivalent. Googling for "NaCl JIT" shows encouraging signs, although the first hit is from May 2011. The general idea of a safe JIT API can be applied to asm.js too. In any event, one would need to write a new back end for LuaJIT2. Bottom line: we're looking into efficient multi-language VM hosting via asm.js and future extensions, but this is obviously a longer road than C/C++ cross-compiling where we've had good early wins (e.g., Unreal Engine).
azakai 13y ago
> You can only asm.js'fy a normal Lua interpreter which is up to 64x slower than LuaJIT on benchmarks Yes, LuaJIT is fast, but even their own numbers are nowhere near 64x being the mean or median, http://luajit.org/performance_x86.html http://luajit.org/performance_x86.html Furthermore, these are microbenchmarks. Large codebases might paint a different picture. I am also not sure why LuaJIT is the most interesting comparison. Yes, LuaJIT is a work of art, but even normal Lua is quite fast, beating Python and Ruby easily. So even a half-speed Lua-VM-in-JS would be competitive with other dynamic languages - which means it is fast enough for many uses. Finally, we can certainly compile VMs that JIT, we just need to create JIT backends for them that emit JS (preferably asm.js). But LuaJIT is more tricky, as you note, because it lacks a portable C interpreter.

backspaces 13y ago

It is SOOO odd to see folks not "get" the JavaScript Everywhere revolution. Node, JS/CoffeeScript, JSON: Server, Client, Network Data. Complete stack, period. C++?? Gack, so yesterday. Python, Ruby, etc .. so without dynamic windows everywhere. Google?? So confused. What's their next project jerked out of our workflow? When is Google coming out of beta? Keep up the good work /be -- Owen