Intel Gen12/Xe Graphics Have AV1 Accelerated Decode – Linux Support Lands

https://www.phoronix.com/scan.php?page=news_item&px=Intel-Gen12-Xe-AV1-Decode-Media

by gardaani • 6 years ago

99 30 6 years ago

Sebb767• 6 years ago

It's going to be highly interesting whether Intel can compete in this market. GPUs are quite hard and, compared CPUs, haven't stagnated much.

hddherman2• 6 years ago

We have definitely moved on from the stagnation era of CPU development, if the advancements of AMD are anything to go by.

esgwpl• 6 years ago

Not to take away from their success but their recent progress have been more like them catching up to Intel. It will be interesting to see if they can truly pull ahead though.

hydroreadsstuff• 6 years ago

If you factor out chip size and clock frequency, they do actually stagnate. They add new features, but legacy rendering performance is improved by single-digit percentage points, I believe.

If you look at A100 compared to V100 for e.g. FP32 FMA performance (not tensor). 14.1TFLOPS -> 19.5 = +38%, for 2x transistors (16->7nm), +35% SMs and 250W->400W is not that great. Note that NVIDIA uses boost clock for all A100 numbers and seems not have published any base clock so far. So their is a chance that actual sustained A100 performance is lower.

Turing GPUs have rather large dies. TU102 754nm vs GP102 471nm. So comparing them as is, isn't quite fair.

On the CPU front Intel used to use rather small dies for consumers (and even use die shrinks to just cram more chips onto a waver -> more $$$), but now that AMD forces their hand, they are giving in. But of course a lot this area goes into extra cores, not single threaded performance (diminishing returns there).

derefr• 6 years ago

legacy rendering performance is improved by single-digit percentage points, I believe.

I feel like one would expect this, given that the rendering engines of any given generation, are architected under specific assumptions about the optimal relative "shape" of their graphics pipeline.

The clearest example being old game consoles. You could write a SNES emulator for the SuperFX coprocessor, that used the host's GPU to render the polygons, but the rendering would not go any faster than it does on the SNES, because the draw commands are just being trickled out as the physics-engine work necessary to update their positions gets done in fits and starts per scan-line. That trickling-out was necessary on a SNES, because there wasn't time to run all that logic during VBLANK; but in the modern era, we have the opposite problem — that the logic could all be completed during VBLANK (with tons of room to spare), but instead is being "dragged out" across 512 HBLANKs, such that the GPU only gets the full picture of the completed scene at the last moment. (Despite the recent source-code leak, rewriting StarFox to make it render at 60FPS or more will not be a trivial process.)

The same thing is true, to a varying extent, of all legacy renderers. They're written for graphical pipelines that just don't match the one we have now. The one we have now is "wider" — more parallel — in so many places, but if it's just being used to recapitulate a long, serial set of fixed-function legacy pipeline stages, that width doesn't help it any.

pizza234• 6 years ago

Well, from the user perspective, chip size and clock are crucial factors, as GPU workloads tend to be parallelizable. Besides, chip size and clock don't come for free, so I think they shouldn't be discarded regardless.

AFAIK, with each generation, Nvidia has increased raw performance by 20-30%, which is significant.

On the other hand, the wall of physical limits is getting closer (which may restrict the chip size), but until then, GPUs are faring very well.

GPUs functionalities also have a very different nature (as you point out), but this can play well for the user. Realism depends on many functionalities, which have plenty of headroom for improvement (in the sense of hardware support); see ray tracing, which supposedly, is going to be significantly faster on Ampere.

tagrun2• 6 years ago

Video encoding/decoding circuitry (which the post is about) is not a part of the GPU, so that's a bit tangential.

ksec• 6 years ago

Well the title would be more accurate as GPGPU Accelerated Decode.

It gives the false assumption that AV1 is being Hardware Accelerated in Intel Xe GPU which often means dedicated decoding block to decode the video codec in lowest energy usage possible.

tagrun2• 6 years ago

That's not GPGPU/compute though and Gen 12+ does have hardware accelerated decoding for AV1:

https://github.com/intel/media-driver/blob/master/README.md#...

"AV1 hardware decoding is supported from Gen12+ platforms."

fulafel• 6 years ago

"With some 33k lines of new code, hardware AV1 decode acceleration is in place for Intel Gen12 graphics" - that would be some tight GPU code!

GPGPU implementation of AV1 would be a useful thing though. Anyone know of implementations?

Intel Gen12/Xe Graphics Have AV1 Accelerated Decode – Linux Support Lands

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