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21 GB/s CSV Parsing Using SIMD on AMD 9950X

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Re: 21 GB/s CSV Parsing Using SIMD on AMD 9950X

#101

Post by wyager »

vardump wrote: post #99
tedunangst wrote: post #86

Earlier quoted context omitted.

I mean, the most interesting part of the article for me: > A bit surprisingly the AVX2 parser on 9950X hit ~20GB/s! That is, it was better than the AVX-512 based parser by ~10%, which is pretty significant for Sep. They fixed it, that's the whole point, but I think there's evidence that AVX-512 doesn't actually benefit consumers that much. I would be willing to settle for a laptop that can only parse 20GB/s and not 2…

That probably just means it's a memory bandwidth bound problem. It's going to be a different story for tasks that require more computation.

You can still saturate an ultrawide vector unit with narrower instructions if you have wide enough dispatch

Re: 21 GB/s CSV Parsing Using SIMD on AMD 9950X

#103

Post by jerryseff »

gnfargbl wrote: post #88
sitkack wrote: post #49

Earlier quoted context omitted.

That is what Intel does, they build up a market (Optane) and then do a rug pull (Depth Cameras). They continue to do this thing where they do a huge push into a new technology, then don't see the uptake and let it die. Instead of building slowly and then at the right time, doing a big push. Optane support was just getting mature in the Linux kernel when they pulled it. And they focused on some weird cost cutting move…

The rugpull on Optane was incredibly frustrating. Intel developed a technology which made really meaningful improvements to workloads in an industry that is full of sticky late adopters (RDBMSes). They kept investing until the point where they had unequivocally made their point and the late adopters were just about getting it... and then killed it! It's hard to understand how they could have played that particular ha…

Optane was incredible. It's insane that Intel dropped this.

Re: 21 GB/s CSV Parsing Using SIMD on AMD 9950X

#105

Post by Aurornis »

chao- wrote: post #38

It feels crazy to me that Intel spent years dedicating die space on consumer SKUs to "make fetch happen" with AVX-512, and as more and more libraries are finally using it, as Intel's goal is achieved, they have removed AVX-512 from their consumer SKUs. It isn't that AMD has better AVX-512 support, which would be an impressive upset on it's own. Instead, it is only that AMD has AVX-512 on consumer CPUs, because Intel…

In this article, they saw the following speeds:

Original: 18 GB/s

AVX2: 20 GB/s

AVX512: 21 GB/s

This is an AMD CPU, but it's clear that the AVX512 benefits are marginal over the AVX2 version. Note that Intel's consumer chips do support AVX2, even on the E-cores.

But there's more to the story: This is a single-threaded benchmark. Intel gave up AVX512 to free up die space for more cores. Intel's top of the line consumer part has 24 cores as a result, whereas AMD's top consumer part has 16. We'd have to look at actual Intel benchmarks to see, but if the AVX2 to AVX512 improvements are marginal, a multithreaded AVX2 version across more cores would likely outperform a multithreaded AVX512 version across fewer cores. Note that Intel's E-cores run AVX2 instructions slower than the P-cores, but again the AVX boost is marginal in this benchmark anyway.

I know people like to get angry at Intel for taking a feature away, but the real-world benefit of having AVX512 instead of only AVX2 is very minimal. In most cases, it's probably offset by having extra cores working on the problem. There are very specific workloads, often single-threaded, that benefit from AVX-512, but on a blended mix of applications and benchmarks I suspect Intel made an informed decision to do what they did.

Re: 21 GB/s CSV Parsing Using SIMD on AMD 9950X

#107

Post by high_na_euv »

sitkack wrote: post #49
chao- wrote: post #38

It feels crazy to me that Intel spent years dedicating die space on consumer SKUs to "make fetch happen" with AVX-512, and as more and more libraries are finally using it, as Intel's goal is achieved, they have removed AVX-512 from their consumer SKUs. It isn't that AMD has better AVX-512 support, which would be an impressive upset on it's own. Instead, it is only that AMD has AVX-512 on consumer CPUs, because Intel…

That is what Intel does, they build up a market (Optane) and then do a rug pull (Depth Cameras). They continue to do this thing where they do a huge push into a new technology, then don't see the uptake and let it die. Instead of building slowly and then at the right time, doing a big push. Optane support was just getting mature in the Linux kernel when they pulled it. And they focused on some weird cost cutting move…

Optane was cancelled because manufacturer sold the fab

Re: 21 GB/s CSV Parsing Using SIMD on AMD 9950X

#108

Post by h4ck_th3_pl4n3t »

zzbn00 wrote: post #15
segmondy wrote: post #11

Earlier quoted context omitted.

lots of folks in Finance, you can share csv with any Finance company and they can process it. It's text.

Humans generate decisions / text information at rates of ~bytes per second at most. There is barely enough humans around to generate 21GB/s of information even if all they did was make financial decisions! So 21 GB/s would be solely algos talking to algos... Given all the investment in the algos, surely they don't need to be exchanging CSV around?

You seem to not realize that most humans are not coders.

And non coders use proprietary software, which usually has an export into CSV or XLS to be compatible with Microsoft Office.

Re: 21 GB/s CSV Parsing Using SIMD on AMD 9950X

#110

Post by neonsunset »

Aurornis wrote: post #105
chao- wrote: post #38

It feels crazy to me that Intel spent years dedicating die space on consumer SKUs to "make fetch happen" with AVX-512, and as more and more libraries are finally using it, as Intel's goal is achieved, they have removed AVX-512 from their consumer SKUs. It isn't that AMD has better AVX-512 support, which would be an impressive upset on it's own. Instead, it is only that AMD has AVX-512 on consumer CPUs, because Intel…

In this article, they saw the following speeds: Original: 18 GB/s AVX2: 20 GB/s AVX512: 21 GB/s This is an AMD CPU, but it's clear that the AVX512 benefits are marginal over the AVX2 version. Note that Intel's consumer chips do support AVX2, even on the E-cores. But there's more to the story: This is a single-threaded benchmark. Intel gave up AVX512 to free up die space for more cores. Intel's top of the line consume…

AVX2 vs AVX512 in this case may be somewhat misleading. In .NET, even if you use 256bit-wide vectors, it will still take advantage of AVX512VL whenever available to fuse chained operations into masked, vpternlogd's, etc.[0] (plus standard operations like stack zeroing, struct copying, string comparison, element search, and other can use the full width)[1]

So to force true AVX2 the benchmark would have to be ran with `DOTNET_EnableAVX512F=0` which I assume is not the case here.

[0]: https://devblogs.microsoft.com/dotnet/performance-improvemen...

[1]: https://devblogs.microsoft.com/dotnet/performance-improvemen...

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