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Ryzen Threadripper Pro 3995WX Spotted

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Re: Ryzen Threadripper Pro 3995WX Spotted

#91

Post by kllrnohj »

Roritharr wrote: post #23

I wonder how much the silicon quality differs on a single Threadripper Chip. It would really be interesting to see if it's feasible to Overclock the best numa node to a degree that gives this a couple of high single thread performance cores comparable to the 3900X or 3950X while retaining stability overall.

> Overclock the best numa node to a degree

Do you mean the best ccx? Or best chiplet? There aren't any numa nodes here, and the cache & memory architecture are already the same as a 3900x.

Per-core & per-ccx overclocking does already exist on ryzen though, should work the same on threadripper.

Re: Ryzen Threadripper Pro 3995WX Spotted

#92

Post by BiasRegularizer »

ajross wrote: post #85
Uehreka wrote: post #12

I feel like 64 cores is getting rather close to a tipping point: What workloads are so massively parallel that they can use 64 cores of x86 but can’t use the thousands of CUDA cores on a Quadro card? I’m sure right now there are workloads that just need particular x86 instructions, but that feels like a temporary problem. Am I wrong about that being a temporary problem (that would feel frustrating)? Are these cores j…

> What workloads are so massively parallel that they can use 64 cores of x86 but can’t use the thousands of CUDA cores on a Quadro card? Building software, for one. C compilers and python interpreters don't run on a GPU. Lots of stuff doesn't run on a GPU. In fact in practice the only things that run on a GPU are the tiny handful of known subproblems that the industry has collectively decided are "GPU problems". Like…

Also, GPU has VERY limited memory and no virtual memory.

Re: Ryzen Threadripper Pro 3995WX Spotted

#93

Post by kllrnohj »

hellofunk wrote: post #68

It’s unclear to me what eight channel memory actually means, I’m not used to seeing that mentioned in casual architecture overviews. What’s the benefit of that? Is that something that a programmer must explicitly take advantage of, or is that just an automatic part of the CPU?

Think RAID 0 but for RAM done by the CPU.

Nearly every consumer CPU for the last 20 years is dual channel, meaning "2 drive RAID 0". If you've seen things like recommendations to get paired DDR memory sticks, this is why. You only get this RAID-like benefit with multiple RAM sticks (just like RAID 0 of a single drive doesn't do anything). It's also why some consumer products have unexpectedly bad performance for the CPU specs - cheaper laptops may skimp here and just run a single stick of memory instead of 2. Which means half the memory bandwidth.

8 channel then means the CPU can do this up to 8 sticks for 8x the bandwidth instead of the more common 2x.

Re: Ryzen Threadripper Pro 3995WX Spotted

#94

Post by jarvist »

Uehreka wrote: post #12

I feel like 64 cores is getting rather close to a tipping point: What workloads are so massively parallel that they can use 64 cores of x86 but can’t use the thousands of CUDA cores on a Quadro card? I’m sure right now there are workloads that just need particular x86 instructions, but that feels like a temporary problem. Am I wrong about that being a temporary problem (that would feel frustrating)? Are these cores j…

Almost all scientific computing. In spite of considerable effort, there are relatively few workloads that use GPUs well, and even for codes which do work on GPU, you tend to end up with partial functionality, and a very restrictive region of parameter space where they work efficiently. (And often you run out of memory very quickly - scientific workloads typically run multi-node and share RAM across the nodes via Global Arrays or equivalent. Using multiple terabytes of memory is absolutely normal.) The computation in deep learning is actually quite simple (matrix-vector operations), and still it has taken considerable effort to develop efficient kernels (such as cuDNN).

The next UK supercomputer is based around AMD's 64 CPU chips for this reason. One concern is that we may now be limited by the shared memory bandwidth. https://www.nextplatform.com/2019/10/18/amd-cpus-will-power-...

Re: Ryzen Threadripper Pro 3995WX Spotted

#95

Post by [deleted] »

Uehreka wrote: post #12

I feel like 64 cores is getting rather close to a tipping point: What workloads are so massively parallel that they can use 64 cores of x86 but can’t use the thousands of CUDA cores on a Quadro card? I’m sure right now there are workloads that just need particular x86 instructions, but that feels like a temporary problem. Am I wrong about that being a temporary problem (that would feel frustrating)? Are these cores j…

[deleted]

Re: Ryzen Threadripper Pro 3995WX Spotted

#96

Post by baybal2 »

ajross wrote: post #85
Uehreka wrote: post #12

I feel like 64 cores is getting rather close to a tipping point: What workloads are so massively parallel that they can use 64 cores of x86 but can’t use the thousands of CUDA cores on a Quadro card? I’m sure right now there are workloads that just need particular x86 instructions, but that feels like a temporary problem. Am I wrong about that being a temporary problem (that would feel frustrating)? Are these cores j…

> What workloads are so massively parallel that they can use 64 cores of x86 but can’t use the thousands of CUDA cores on a Quadro card? Building software, for one. C compilers and python interpreters don't run on a GPU. Lots of stuff doesn't run on a GPU. In fact in practice the only things that run on a GPU are the tiny handful of known subproblems that the industry has collectively decided are "GPU problems". Like…

> Building software

Well, the problem with that is that no make system can utilise so much core. Even linux kernel, probably the biggest C project in mainstream use, can not consistently load even 16 cores with mostly handwritten makefiles.

P.S.

I do not say that building software is not CPU parallelisable in principles, I'm saying that regular make systems have trouble handing big number of parallel tasks in practice, even in big, well run projects that use handwritten makefiles.

Re: Ryzen Threadripper Pro 3995WX Spotted

#97

Post by rational_indian »

BiasRegularizer wrote: post #92
ajross wrote: post #85

Earlier quoted context omitted.

> What workloads are so massively parallel that they can use 64 cores of x86 but can’t use the thousands of CUDA cores on a Quadro card? Building software, for one. C compilers and python interpreters don't run on a GPU. Lots of stuff doesn't run on a GPU. In fact in practice the only things that run on a GPU are the tiny handful of known subproblems that the industry has collectively decided are "GPU problems". Like…

Also, GPU has VERY limited memory and no virtual memory.

> VERY limited memory and no virtual memory

This is incorrect.

Re: Ryzen Threadripper Pro 3995WX Spotted

#98

Post by ajross »

baybal2 wrote: post #96
ajross wrote: post #85

Earlier quoted context omitted.

> What workloads are so massively parallel that they can use 64 cores of x86 but can’t use the thousands of CUDA cores on a Quadro card? Building software, for one. C compilers and python interpreters don't run on a GPU. Lots of stuff doesn't run on a GPU. In fact in practice the only things that run on a GPU are the tiny handful of known subproblems that the industry has collectively decided are "GPU problems". Like…

> Building software Well, the problem with that is that no make system can utilise so much core. Even linux kernel, probably the biggest C project in mainstream use, can not consistently load even 16 cores with mostly handwritten makefiles. P.S. I do not say that building software is not CPU parallelisable in principles, I'm saying that regular make systems have trouble handing big number of parallel tasks in practic…

That's... not true at all. A kernel build will be as parallelizable as you like. I do kernel builds fairly regularly on 56 and 64 core hosts and in fact the build time is quite linear with core count. (The ramdisk packing provided by the distro at "make install" time tends to be what hurts scaling, FWIW).

And my day job involves lots of iterations over the Zephyr test suite, which builds and runs hundreds of individual test apps X dozens of platforms. This is almost a pure build-time problem and scales very linearly indeed.

Re: Ryzen Threadripper Pro 3995WX Spotted

#99

Post by emidln »

baybal2 wrote: post #96
ajross wrote: post #85

Earlier quoted context omitted.

> What workloads are so massively parallel that they can use 64 cores of x86 but can’t use the thousands of CUDA cores on a Quadro card? Building software, for one. C compilers and python interpreters don't run on a GPU. Lots of stuff doesn't run on a GPU. In fact in practice the only things that run on a GPU are the tiny handful of known subproblems that the industry has collectively decided are "GPU problems". Like…

> Building software Well, the problem with that is that no make system can utilise so much core. Even linux kernel, probably the biggest C project in mainstream use, can not consistently load even 16 cores with mostly handwritten makefiles. P.S. I do not say that building software is not CPU parallelisable in principles, I'm saying that regular make systems have trouble handing big number of parallel tasks in practic…

Bazel utilizes the cores near linearly. It even makes use of remote cores in an efficient manner for compiling c++. 128 thread and 256 thread machines are great if you also have enough ddr4 to let each gcc/clang do their thing.

Re: Ryzen Threadripper Pro 3995WX Spotted

#100

Post by gameswithgo »

Uehreka wrote: post #12

I feel like 64 cores is getting rather close to a tipping point: What workloads are so massively parallel that they can use 64 cores of x86 but can’t use the thousands of CUDA cores on a Quadro card? I’m sure right now there are workloads that just need particular x86 instructions, but that feels like a temporary problem. Am I wrong about that being a temporary problem (that would feel frustrating)? Are these cores j…

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