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> Why does an 8 core mac have moments that it is so busy I can't even click anything but only see a pinwheel? Take a moment to consider your expectations of th

> Why does an 8 core mac have moments that it is so busy I can't even click anything but only see a pinwheel? Take a moment to consider your expectations of that operating system, and the expectations upon software used thirty years ago. Thirty years ago it was uncommon for users to expect more than one application to be operating at once, and so scheduling resource use wasn't an issue. Now, your PC has ll manner of processes doing work while you go about your business; applications are polling for updates from remote servers, media players are piping streams to a central mixer and attempting to play them simultaneously and seamlessly, your display is drawn with all manner of tricks to improve visual appeal and the _feeling_ of responsiveness, and your browser is going all this over again in the dozens of tabs you have open simultaneously. So once in a while a resource lock is held for a little too long, or an interrupt just happens to cause a cascade of locks that block your system for a period, or you stumble across a corner-case that wasn't accounted for by the developers. Frankly, it's nothing short of a miracle that PCs are able to operate as well as they do, despite our best efforts to overload them with unnecessary work. And yes, I too hate Electron, but in all my decades of working on PCs I can't really recall a time that was as... Actually, BeOS was pretty f'n great.

pjc50 9y ago
I don't think responsiveness of the system is an unreasonable expectation. App A should not be able to perform a denial-of-service on app B simply by being badly programmed.
- digi_owl 9y ago
  I dunno. Deep down the computer is still linear. Yes we do all kinds of tricks with context switching to make it seem like it is doing a whole bunch of things at the same time. But if we had visualized the activity in human terms, it would be an assembly line that is constantly switching between cars, trucks, scooters and whatsnot at a simply astonishing rate.
  - willglynn 9y ago
    That hasn't been true in many many years. Multicore processors literally run several things at the same time. Even a single core can literally run several instructions at the same time thanks to instruction level parallelism, in addition to reordering instructions, predicting and speculatively executing branches, etc. The processor also has a cache subsystem which is interacting with the memory subsystem on behalf of the code -- but this all works in parallel with the code. Memory operations are executed as asynchronously as possible in order to maximize performance. What's more, outside a processor, what we call "a computer" is actually a collection of many interconnected systems all working in parallel. The northbridge and southbridge chips coordinate with the instructions running on the CPU, but they're not synchronously controlled by the CPU, which means they are legitimately doing other things at the same time as the CPU. When you read something off disk, your CPU sends a command to an IO controller, which sends a command to a controller in the disk, which sends a command to a motor or to some flash chips. Eventually the disk controller gets the data you requested and the process goes back the other way. Disks have contained independent coprocessors for ages; "IDE" stands for "Integrated Drive Electronics", and logical block addressing (which requires on-disk smarts) has been standard since about 1996. Some part of your graphics card is always busy outputting a video signal at (say) 60 FPS, even while some other part of your graphics card is working through a command queue to draw the next frame. Audio, Ethernet, wifi, Bluetooth, all likewise happen simultaneously, with their own specialized processors, configuration registers, and signaling mechanisms. Computers do lots of things simultaneously. It's not an illusion caused by rapid context switching. Frankly, the illusion is that anything in the computer is linear :-)
    - willglynn 9y ago
      Following up on that last thought, about how linearity is the illusion: this talk explains in detail the Herculean effort expended by hardware and language designers to create something comprehensible on top of the complexities of today's memory subsystems. It's three hours and focused on how it affects C++, but IMO it's well worth the time and accessible to anyone who has some idea of what happens at the machine code level. https://channel9.msdn.com/Shows/Going+Deep/Cpp-and-Beyond-2012-Herb-Sutter-atomic-Weapons-1-of-2 https://channel9.msdn.com/Shows/Going+Deep/Cpp-and-Beyond-20... https://channel9.msdn.com/Shows/Going+Deep/Cpp-and-Beyond-2012-Herb-Sutter-atomic-Weapons-2-of-2 https://channel9.msdn.com/Shows/Going+Deep/Cpp-and-Beyond-20...
GuiA 9y ago
Thirty years ago is cheating. How about 15 years ago? I was doing everything you describe as part of my daily computer use (a few browser windows open, a text editor running, a multimedia player, an IM and mail client running, etc) and had the same performance and usability frustrations. The main difference is that if I render a video now, I'll do it in 4k instead of 640x480, and that if I download a game, it's 50GB instead of 500MB. But scalin in that direction is expected; my machine isn't any more stable, or anything that goes in the way of the examplea described in the article. If I showed my mobile phone to 2002 me, they'd be extremely impressed. If I showed the form factor and specs of my laptop, they'd be extremely impressed. But if I showed them how I use my desktop OS? The only cool thing would be Dropbox, I think.
- dleslie 9y ago
  We've hit a local maximum with the current desktop metaphor; moving in any other direction means losing value until the next peak can be found. This is happening in the mobile space, as you noted; it will happen in AR next.
- hossbeast 9y ago
  That is a very interesting thought exercise. 2002 me might also ask, "where's the screensaver?"

pjc50 9y ago

I don't think responsiveness of the system is an unreasonable expectation. App A should not be able to perform a denial-of-service on app B simply by being badly programmed.

digi_owl 9y ago
I dunno. Deep down the computer is still linear. Yes we do all kinds of tricks with context switching to make it seem like it is doing a whole bunch of things at the same time. But if we had visualized the activity in human terms, it would be an assembly line that is constantly switching between cars, trucks, scooters and whatsnot at a simply astonishing rate.
- willglynn 9y ago
  That hasn't been true in many many years. Multicore processors literally run several things at the same time. Even a single core can literally run several instructions at the same time thanks to instruction level parallelism, in addition to reordering instructions, predicting and speculatively executing branches, etc. The processor also has a cache subsystem which is interacting with the memory subsystem on behalf of the code -- but this all works in parallel with the code. Memory operations are executed as asynchronously as possible in order to maximize performance. What's more, outside a processor, what we call "a computer" is actually a collection of many interconnected systems all working in parallel. The northbridge and southbridge chips coordinate with the instructions running on the CPU, but they're not synchronously controlled by the CPU, which means they are legitimately doing other things at the same time as the CPU. When you read something off disk, your CPU sends a command to an IO controller, which sends a command to a controller in the disk, which sends a command to a motor or to some flash chips. Eventually the disk controller gets the data you requested and the process goes back the other way. Disks have contained independent coprocessors for ages; "IDE" stands for "Integrated Drive Electronics", and logical block addressing (which requires on-disk smarts) has been standard since about 1996. Some part of your graphics card is always busy outputting a video signal at (say) 60 FPS, even while some other part of your graphics card is working through a command queue to draw the next frame. Audio, Ethernet, wifi, Bluetooth, all likewise happen simultaneously, with their own specialized processors, configuration registers, and signaling mechanisms. Computers do lots of things simultaneously. It's not an illusion caused by rapid context switching. Frankly, the illusion is that anything in the computer is linear :-)
  - willglynn 9y ago
    Following up on that last thought, about how linearity is the illusion: this talk explains in detail the Herculean effort expended by hardware and language designers to create something comprehensible on top of the complexities of today's memory subsystems. It's three hours and focused on how it affects C++, but IMO it's well worth the time and accessible to anyone who has some idea of what happens at the machine code level. https://channel9.msdn.com/Shows/Going+Deep/Cpp-and-Beyond-2012-Herb-Sutter-atomic-Weapons-1-of-2 https://channel9.msdn.com/Shows/Going+Deep/Cpp-and-Beyond-20... https://channel9.msdn.com/Shows/Going+Deep/Cpp-and-Beyond-2012-Herb-Sutter-atomic-Weapons-2-of-2 https://channel9.msdn.com/Shows/Going+Deep/Cpp-and-Beyond-20...

GuiA 9y ago

Thirty years ago is cheating. How about 15 years ago? I was doing everything you describe as part of my daily computer use (a few browser windows open, a text editor running, a multimedia player, an IM and mail client running, etc) and had the same performance and usability frustrations. The main difference is that if I render a video now, I'll do it in 4k instead of 640x480, and that if I download a game, it's 50GB instead of 500MB. But scalin in that direction is expected; my machine isn't any more stable, or anything that goes in the way of the examplea described in the article. If I showed my mobile phone to 2002 me, they'd be extremely impressed. If I showed the form factor and specs of my laptop, they'd be extremely impressed. But if I showed them how I use my desktop OS? The only cool thing would be Dropbox, I think.

dleslie 9y ago
We've hit a local maximum with the current desktop metaphor; moving in any other direction means losing value until the next peak can be found. This is happening in the mobile space, as you noted; it will happen in AR next.
hossbeast 9y ago
That is a very interesting thought exercise. 2002 me might also ask, "where's the screensaver?"