"When you can't scale up, scale out."
GPUs have strong potential for improvement, and moving workloads to them helps on multiple fronts: performance, cost, power consumption.
The Great CPU Stagnation
71–80 of 222 posts
Re: The Great CPU Stagnation
#72The Great x86 CPU Stagnation? ARM seems to have made some great leaps forward in recent years.
ARM has seen increased adoption, but the chips themselves aren't much different than 4-5 years ago.
Re: The Great CPU Stagnation
#73Re: The Great CPU Stagnation
#74Earlier quoted context omitted.
tl;dr New materials can help, but "resistive losses" aren't really the driving factor. The energy is a mix of leakage current and active current. Leakage current can be thought of as resistance - it's how much current flows through a transistor that's off. This can be better based on the material, but gets harder with smaller transistors. (Thinking about quantum tunneling as a resistance is good to get intuition, but…
From what I understand while these two do contribute a lot to power usage, they don't really contribute that much to heating by themselves? Leakage should happen all the same in a processor that's completely idle and those typically don't heat up much. For higher clock speeds specifically I still don't see how lower resistance isn't key.
>while these two do contribute a lot to power usage, they don't really contribute that much to heating
Those are the same thing. Or at least close enough as makes no practical difference. Only an extremely tiny fraction of the power used but a CPU is becoming anything other than heat.
Re: The Great CPU Stagnation
#75In fact the CPU stagnation is worse. In contrast to the shrinking chip size and higher frequencies of past scaling laws, CPU core count does not easily translate to performance gains. It needs specialized and careful designed software to tap the capability. In fact if CPU core count did translate more easily to performance gains I think already with the existing CPU's we'd have a fairly signficant one-time boost. May…
multi-core architectures have been optimized for web servers i.e. tons of clients hitting relatively simple backend processes. also, my day-to-day gui workstation (ancient xeon mac) gets far more core usage than my dev server (threadripper) which is honestly kind of a waste of money, but it's shiny so i bought it anyway. it should last me a decade+ just like my gui workstation has.
now that single-core GPU/CPU/TPU/whatever performance is back on the front burner i think we'll see some horsepower and compiler improvements over the next few years. luckily the i/o problem has made great strides in the meantime so network/memory/storage will be there to support it, unlike in the past. ecc ram is also plummeting in cost, so that's good.
Re: The Great CPU Stagnation
#76We've known about this for a long time. Everyone expected it to happen. There are some key upcoming technologies that have the potential to cause a step in scaling (CFETs, backside power delivery) but it's still not going to be anywhere near Moore's law levels. I think this is part of why GPU power is skyrocketing and why Apple, Qualcomm, and the like are trying to shift towards services.
> We've known about this for a long time. Everyone expected it to happen.
Absolutely. The 2006 "A View from Berkeley" is still a great paper [1]. And we still have a long ways to go on this recommendation:
> To maximize application efficiency, programming models should support a wide range of data types and successful models of parallelism
We are still stuck in the winner-take-all mindset when it comes to software development.
[1] https://www2.eecs.berkeley.edu/Pubs/TechRpts/2006/EECS-2006-...
Re: The Great CPU Stagnation
#77Zen 4C is somewhat delayed but should be an interesting shift on these great numbers. It's a significsntly smaller core, first for servers, then latter big/little consumer parts.
Maybe the IPC or GHz really will be significantly lower, but I tend to think things like cache size will be the biggest hit, and that cache size change wouldn't show up in these graphs. Essentially, same number of transistors, but more compute less cache is my guess. But perhaps the cores really are smaller & narrower & the IPC * GHz rating doesnt budge much!
Re: The Great CPU Stagnation
#78Earlier quoted context omitted.
> I think this is part of why GPU power is skyrocketing and why Apple, Qualcomm, and the like are trying to shift towards services. IMHO it's only a very small part of why GPU power consumption is going up. The main reason is the completely unnecessary chase for the performance crown. From personal testing: my GPU manages to get 95% of its peak performance while being power limited to 80%. So the in order to squeeze…
I would also think that GPU workloads have something to do with it. Almost none are serial workflows, and instead highly parallel work. GPU workloads will eventually run into the same scaling limits. That is we will be unable to speed up each execution unit any further, or the primary work we give the GPU will not be able to be split into more threads and accomplish useful work.
Good point about the workload. On the other hand, typical GPU tasks seem to be scalable basically ad-infinitum as graphics moved from fixed-function pipelines to per-pixel shaders to raytracing and path tracing.
So maybe GPUs still have some room until they run into the same problem as CPUs.
Re: The Great CPU Stagnation
#79I think you should factor in inflation. Inflation has been significant recently.
Also you are not comparing to Intel's cost per core which would show that this pricing issue is not new. I think you just didn't notice it before.
Re: The Great CPU Stagnation
#80Up until this year, CPU was never my limiting factor. We always used multithreaded or GPUs.
This year has seen a need for a decent CPU for occasions where we must single thread. Both Local AI and python development.
For so long, we never maxed out our CPU.