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In 2015 I find the claim that you could beat Intel by 1000x with a better arch much more idiotic than I did in 2008. Because apart from it being idiotic from a

by _yosefk 11y ago

In 2015 I find the claim that you could beat Intel by 1000x with a better arch much more idiotic than I did in 2008. Because apart from it being idiotic from a technical standpoint I'm now dumbfounded by the extent of its idiocy from the business angle. If you're so smart, what's stopping you from making a trillion dollars off it? You need to be an Alan Kay to utter such bullshit repeatedly and still have crowds of worshippers taking each of your utterances as gospel while chanting that you singlehandedly invented computing as we know it.

creshal 11y ago
You'd think there are enough universities working on research processor architectures that a 10x would have popped up by now, if you can theoretically make a 1000x one. I'd rather point the blame on software: If we were banging on hardware directly like in the 70s, we'd probably see a massive performance boost, too… just hope that your customers accidentally happen to have the hardware you optimized for and don't want to run anything else on it.
CyberDildonics 11y ago
I don't know if 1000x is something that can be backed up, but the difference between a program written with poor memory locality and one written with great locality plus 256 bit SIMD can give a performance boost of around 100x. This isn't theoretical, I've done it personally and this is just one core. So the claims are anything but outrageous although that is basically what GPUs are - transistors going to actual FLOPS instead of dealing with memory latency. Intel cores however are structured like this because most code isn't written with cache locality in mind, they are written in god awful pointer chasing spaghetti styles so all the work that Intel puts in to make that go fast pays off. Skylake almost had SIMD scatter and gather, which could have been an enormous boost to properly written software, but they had no reason to put it in when they are curb stomping AMD on one hand, and very little software takes advantage of the SIMD units they have now on the other.
sklogic 11y ago
It's trivial to beat a generic CPU by 1000x with a specialised ASIC or even an FPGA in many cases (think cryptography, for example).
- adwn 11y ago
  Make that a few cases for FPGAs. Modern desktop CPUs are incredibly fast and run circles around modern FPGAs, even for many specialized, repetitive, parallel, integer-computation-bound algorithms. Of course, there are a couple of applications where FPGAs are actually faster than CPUs. Source: I'm an FPGA developer with a software engineering background.
  - sklogic 11y ago
    > Modern desktop CPUs are incredibly fast and run circles around modern FPGAs Yep. At a tiny price of tenths of W of TDP. FPGAs shine in communication, not in computing. Fast isolated memories, wide channels (as wide as you like), etc. And there are far more tasks where you have to juggle gigabytes of data as fast as possible than the tasks where you have to maximise FLOPS.
  - kragen 11y ago
    That's fascinating and startling! Why is that? Is it that the FPGA's cost per bit operation is just so many times larger than the CPU's that the FPGA can't compete? Where do GPUs fit in?
    - adwn 11y ago
      Several factors: 1) FPGAs are much slower due to the overhead of the flexibility they provide. With a lot of effort, you can get some FPGA designs (not even all of them!) to maybe 400 MHz on the more expensive FPGAs, and then it will do much less per cycle compared to an ASIC (CPUs are ASICs), so you need deep pipelines, with all the cost, complexity, and restrictions this entails. 2) CPUs have a lot of memory on-chip in the form of cache (several MiB), and they have sophisticated prefetch logic. In FPGAs, memory comes in several 100 blocks of, say, 4 kiB (depending on FPGA model). All memory management is purely manual. 3) CPUs tend to have a much higher external memory bandwidth. 4) Complex operations that are not directly provided by the FPGA fabric, like floating-point arithmetic or large memories with more than two ports, are expensive in terms of area and performance. 5) Modern desktop CPUs are incredibly well optimized: high clock frequency, out-of-order execution, superscalarity with several execution units, SIMD, automatic cache management, branch prediction, ... It's just very hard to beat that, and this is only possible for certain, very restricted applications. Highly parallel DSP (Digital Signal Processing) with integer/fixed-point arithmetic comes to mind.
stevejones 11y ago
You'd be better off working out a way to compile smalltalk to FPGA.

by _yosefk 11y ago

creshal 11y ago

You'd think there are enough universities working on research processor architectures that a 10x would have popped up by now, if you can theoretically make a 1000x one. I'd rather point the blame on software: If we were banging on hardware directly like in the 70s, we'd probably see a massive performance boost, too… just hope that your customers accidentally happen to have the hardware you optimized for and don't want to run anything else on it.

CyberDildonics 11y ago

I don't know if 1000x is something that can be backed up, but the difference between a program written with poor memory locality and one written with great locality plus 256 bit SIMD can give a performance boost of around 100x. This isn't theoretical, I've done it personally and this is just one core. So the claims are anything but outrageous although that is basically what GPUs are - transistors going to actual FLOPS instead of dealing with memory latency. Intel cores however are structured like this because most code isn't written with cache locality in mind, they are written in god awful pointer chasing spaghetti styles so all the work that Intel puts in to make that go fast pays off. Skylake almost had SIMD scatter and gather, which could have been an enormous boost to properly written software, but they had no reason to put it in when they are curb stomping AMD on one hand, and very little software takes advantage of the SIMD units they have now on the other.

sklogic 11y ago

It's trivial to beat a generic CPU by 1000x with a specialised ASIC or even an FPGA in many cases (think cryptography, for example).

adwn 11y ago
Make that a few cases for FPGAs. Modern desktop CPUs are incredibly fast and run circles around modern FPGAs, even for many specialized, repetitive, parallel, integer-computation-bound algorithms. Of course, there are a couple of applications where FPGAs are actually faster than CPUs. Source: I'm an FPGA developer with a software engineering background.
- sklogic 11y ago
  > Modern desktop CPUs are incredibly fast and run circles around modern FPGAs Yep. At a tiny price of tenths of W of TDP. FPGAs shine in communication, not in computing. Fast isolated memories, wide channels (as wide as you like), etc. And there are far more tasks where you have to juggle gigabytes of data as fast as possible than the tasks where you have to maximise FLOPS.
- kragen 11y ago
  That's fascinating and startling! Why is that? Is it that the FPGA's cost per bit operation is just so many times larger than the CPU's that the FPGA can't compete? Where do GPUs fit in?
  - adwn 11y ago
    Several factors: 1) FPGAs are much slower due to the overhead of the flexibility they provide. With a lot of effort, you can get some FPGA designs (not even all of them!) to maybe 400 MHz on the more expensive FPGAs, and then it will do much less per cycle compared to an ASIC (CPUs are ASICs), so you need deep pipelines, with all the cost, complexity, and restrictions this entails. 2) CPUs have a lot of memory on-chip in the form of cache (several MiB), and they have sophisticated prefetch logic. In FPGAs, memory comes in several 100 blocks of, say, 4 kiB (depending on FPGA model). All memory management is purely manual. 3) CPUs tend to have a much higher external memory bandwidth. 4) Complex operations that are not directly provided by the FPGA fabric, like floating-point arithmetic or large memories with more than two ports, are expensive in terms of area and performance. 5) Modern desktop CPUs are incredibly well optimized: high clock frequency, out-of-order execution, superscalarity with several execution units, SIMD, automatic cache management, branch prediction, ... It's just very hard to beat that, and this is only possible for certain, very restricted applications. Highly parallel DSP (Digital Signal Processing) with integer/fixed-point arithmetic comes to mind.

stevejones 11y ago

You'd be better off working out a way to compile smalltalk to FPGA.