FFmpeg Is Ripe For More AVX-512 Optimizations

[phoronix]

Phoronix: FFmpeg Is Ripe For More AVX-512 Optimizations

There is already some AVX-512 optimizations for software contained within the FFmpeg multimedia library, but there is room for greater AVX-512 usage especially now with AMD supporting this Advanced Vector Extensions expansion and the latest Intel Xeon CPUs having little associated cost now with AVX-512 use...

https://www.phoronix.com/news/FFmpeg-Ripe-For-More-AVX-512

[Joe2021]

It is becoming more and more a pita that current Alder Lake and Raptor Lake CPUs do not support AVX512, as it becomes more and more attractive recently. In my understanding the support had to be removed as the efficiency cores lack those instructions, and both performance and efficiency cores have to have the same instruction set.

A possible solution would be to integrate a very basic AVX512 implementation with the efficiency cores. It could be slow, even very slow, the purpose is just to get their instruction set complete, so that an AVX512 process is not going to crash when migrated to an efficiency core. Another solution would be to bind AVX512 processes to performance cores exclusively. That approach would require software support. Each process would have to tell the kernel/scheduler whether he is going to execute AVX512 instructions or not.

I just hope that intel will bring it back in the 14th generation.

[stormcrow]

I just hope they implement a check to see if they should use AVX-512 given the history of the instruction in Intel systems. There's no reason they can't check for problematic generations with an override to enable it regardless of the generation check result.

[ayumu]

It is becoming more and more a pita that current Alder Lake and Raptor Lake CPUs do not support AVX512, as it becomes more and more attractive recently. In my understanding the support had to be removed as the efficiency cores lack those instructions, and both performance and efficiency cores have to have the same instruction set.

Next time, buy AMD.

[stormcrow]

Next time, buy AMD.

And not have AVX-512 at all. (Cuz only the most recent CPU release has it, which is an expensive platform).

But it is amusing that AMD eventually integrated it and got it right, while it took Intel several very public screw ups to make it useful.. then drop it entirely on desktop parts. So ... not have it, or have it but not really in a useful way... decisions decisions....

[ms178]

Next time, buy AMD.

It's fair to critizice Intel for product decisions that hurt their competitive stance. AMD made some mistakes of their own, e.g. launching AM5 without DDR4 support. It is really a tough call for consumers currently as AMD's AM5 platform is just too expensive overall and lacks the multi-core performance in core-heavy applications, this does hurt their competitive stance especially in the mid-range segment against Intel's offerings where I would be looking for a CPU upgrade. In my eyes, current offerings of both companies are equally unattractive as I optimize for price/performance in games and highly multi-threaded applications. Hence I prolong my purchase decision even further until one of them offers me something more compelling for a fair price: high multi-threaded application and gaming performance on an affordable platform for a fair price with AVX-512 and lots of cache.

[TemplarGR]

It is becoming more and more a pita that current Alder Lake and Raptor Lake CPUs do not support AVX512, as it becomes more and more attractive recently. In my understanding the support had to be removed as the efficiency cores lack those instructions, and both performance and efficiency cores have to have the same instruction set.

A possible solution would be to integrate a very basic AVX512 implementation with the efficiency cores. It could be slow, even very slow, the purpose is just to get their instruction set complete, so that an AVX512 process is not going to crash when migrated to an efficiency core. Another solution would be to bind AVX512 processes to performance cores exclusively. That approach would require software support. Each process would have to tell the kernel/scheduler whether he is going to execute AVX512 instructions or not.

I just hope that intel will bring it back in the 14th generation.

Actually, efficiency cores already contain avx512. They just do not enable it because they haven't certified it. Possibly for cost saving or frequency achieving reasons. Some people had enabled avx512 on alder lake, but it could be problematic if you had a bad chip, and no one knows because Intel never tested it. It could output garbage. I suppose future gens will have certified avx512 again because the reasons for not certifying it were fixed.

[TemplarGR]

Next time, buy AMD.

All should boycott AMD, because they always show their corporate anti-consumer face when they feel they have a semi-decent product to sell. At least with Intel, even when they mopped the floor with AMD's trash chips, they still offered reasonable products at reasonable prices to consumers. For example when Haswell was new, Intel had been trashing AMD for many years, yet they still didn't overinflate their prices out of people's reach, like AMD does. Intel still offers affordable value for money chips TODAY, even dgpus these days...

[Linuxxx]

Actually, efficiency cores already contain avx512. They just do not enable it because they haven't certified it. Possibly for cost saving or frequency achieving reasons. Some people had enabled avx512 on alder lake, but it could be problematic if you had a bad chip, and no one knows because Intel never tested it. It could output garbage. I suppose future gens will have certified avx512 again because the reasons for not certifying it were fixed.

Nah, you got that wrong:

The E-cores only recently gained AVX2 support.

Early Alder Lake revisions had the unverified AVX-512 silicon, which could only be enabled when disabling the E-cores via BIOS/UEFI.

Later versions had the AVX-512 part fused off, though.

[Linuxxx]

It is becoming more and more a pita that current Alder Lake and Raptor Lake CPUs do not support AVX512, as it becomes more and more attractive recently. In my understanding the support had to be removed as the efficiency cores lack those instructions, and both performance and efficiency cores have to have the same instruction set.

A possible solution would be to integrate a very basic AVX512 implementation with the efficiency cores. It could be slow, even very slow, the purpose is just to get their instruction set complete, so that an AVX512 process is not going to crash when migrated to an efficiency core. Another solution would be to bind AVX512 processes to performance cores exclusively. That approach would require software support. Each process would have to tell the kernel/scheduler whether he is going to execute AVX512 instructions or not.

I just hope that intel will bring it back in the 14th generation.

Early indications via Intel's official instruction manual show absolutely no sign at all that AVX-512 will return for 14th gen. [Meteor Lake]