Welcome to Doom9's Forum, THE in-place to be for everyone interested in DVD conversion.

Before you start posting please read the forum rules. By posting to this forum you agree to abide by the rules.

 

Go Back   Doom9's Forum > Video Encoding > High Efficiency Video Coding (HEVC)

Reply
 
Thread Tools Search this Thread Display Modes
Old 19th April 2024, 12:17   #9281  |  Link
tormento
Acid fr0g
 
tormento's Avatar
 
Join Date: May 2002
Location: Italy
Posts: 2,586
Quote:
Originally Posted by excellentswordfight View Post
But AFAIK the downclocking of AVX512 load have been improved since its introduction, and was less of an issue on consumer desktop models were frequency control is possible. But given what i've seen, i'm pretty sure that running it with AVX512 produces worse performance/watt.
Itís proven that AVX512 has more performance per watt. About downclocking: if you have a powerful heatsink AFAIK you can disable downclocking in bios.
__________________
@turment on Telegram
tormento is offline   Reply With Quote
Old 19th April 2024, 14:38   #9282  |  Link
excellentswordfight
Lost my old account :(
 
Join Date: Jul 2017
Posts: 326
Quote:
Originally Posted by tormento View Post
It’s proven that AVX512 has more performance per watt
Proven? For all systems with all software? Its pretty much a fact that has been worse for my cases; were enterprise-server hardware has been used. These systems are pretty strict in staying within it's power-specification, so when I get worse performance with AVX512 enabled, but it consumes the same amount of power (I have not messured the powerdraw this mind you, but im pretty sure thats the case given tempeture and freqency readings), then it means that it has a negative impact on performance/w. There are software were AVX512 instructions can do wonders, were it boosts performance by a great ammount, and there im sure that it has performance per watts benefits. But for x265, the performance gains of AVX512 are not that big, and at least with older generation hardware performance per watt has been lower, so unless you also increase power it have given me no gains.
Quote:
About downclocking: if you have a powerful heatsink AFAIK you can disable downclocking in bios.
Yes, and thats also why i wrote:

"...less of an issue on consumer desktop models were frequency control is possible"

I have only tested AVX512 on Xeon/server hardware, and my old ice lake laptop. But as I said, I will try it on Sapphire Rapids, it will be interesting to see how it has been improved, cause first gen, both xeon and consumer (ice-lake) the downclocking rather big.

Last edited by excellentswordfight; 19th April 2024 at 14:53.
excellentswordfight is offline   Reply With Quote
Old 19th April 2024, 17:10   #9283  |  Link
nevcairiel
Registered Developer
 
Join Date: Mar 2010
Location: Hamburg/Germany
Posts: 10,349
AVX512 benefits start if you use it well and thoroughly, using it sparsely or inefficiently can cause more overhead then gain.
Blanket statements never make sense with complex optimizations and complex software. Test your own use-case on your own hardware.
__________________
LAV Filters - open source ffmpeg based media splitter and decoders
nevcairiel is offline   Reply With Quote
Old 19th April 2024, 23:18   #9284  |  Link
Atak_Snajpera
RipBot264 author
 
Atak_Snajpera's Avatar
 
Join Date: May 2006
Location: Poland
Posts: 7,817
Avx512 will be soon abandoned by Intel. AVX10 is a new toy.
Atak_Snajpera is offline   Reply With Quote
Old 22nd April 2024, 04:22   #9285  |  Link
MeteorRain
結城有紀
 
Join Date: Dec 2003
Location: Oregon
Posts: 895
Quote:
Originally Posted by DMD View Post
I apologize but maybe that is why in the latest release of Patman86 the avx512 version does not appear?
https://github.com/Patman86/x265-Mod-by-Patman/releases

Thank you
That's just a targeted build, which affects everything other than the core part. The core will still run at different instruction set (meaning you should be able to use AVX512 on a sandy bridge build if you wish). Only the C++ code (which is not part of the core parts) will target at a different instruction set.

Quote:
Originally Posted by tormento View Post
I'd be curious to see AVX2 vs AVX512 performances of a very noisy source in very slow/placebo preset on modern CPUs.
Unfortunately the choice for Intel is now limited to 11 series and Xeons.
I need to decide if to go with Arrow Lake or Zen 5.
Not having AVX512 could be a big no no, as a lot of plugins and software that I use support that instruction set.
AVX10 for Arrow Lake is a big enigma, as it's not completely confirmed if it will be 10.1 (no AVX512) or 10.2.
AVX512 on different CPUs with different implementations will behave differently. On Zen4 you should generally see slight improvement with AVX512, while on an Intel CPU you'll see some throttling and slow down if you mix AVX512 workload with AVX2 ones.

Zen4 basically runs AVX512 on AVX2 platform, but since some AVX512 instructions are more efficient than their plain AVX2 equivalent, speed sees some improvement.
Intel CPUs runs AVX512 natively, so they do get great improvement. However Intel CPU has that infamous clock throttling so it clocks lower, impacting normal workloads.

It'll end up being a personal preference. AVX10 is a new thing and will take time to adopt. And AVX10 is, well, to just put "AVX512" back to existing product line.

Just my 2 cents.
__________________
My Projects
x265 - Yuuki-Asuna-mod
TS - ADTS AAC Splitter | LATM AAC Splitter | BS4K-ASS
Neo AviSynth+ filters - F3KDB | FFT3D | DFTTest | MiniDeen | Temporal Median
MeteorRain is offline   Reply With Quote
Old 22nd April 2024, 11:26   #9286  |  Link
tormento
Acid fr0g
 
tormento's Avatar
 
Join Date: May 2002
Location: Italy
Posts: 2,586
Quote:
Originally Posted by MeteorRain View Post
It'll end up being a personal preference. AVX10 is a new thing and will take time to adopt. And AVX10 is, well, to just put "AVX512" back to existing product line.
AVX 10.1 will be a subset of AVX512. With 10.2 they will embrace and improve AVX512.
__________________
@turment on Telegram
tormento is offline   Reply With Quote
Old 22nd April 2024, 11:35   #9287  |  Link
Boulder
Pig on the wing
 
Boulder's Avatar
 
Join Date: Mar 2002
Location: Finland
Posts: 5,734
I really wouldn't hold my breath waiting for x265 to get big optimizations regarding any new instruction sets.
__________________
And if the band you're in starts playing different tunes
I'll see you on the dark side of the Moon...
Boulder is offline   Reply With Quote
Old Yesterday, 19:25   #9288  |  Link
benwaggoner
Moderator
 
Join Date: Jan 2006
Location: Portland, OR
Posts: 4,783
Quote:
Originally Posted by MeteorRain View Post
AVX512 on different CPUs with different implementations will behave differently. On Zen4 you should generally see slight improvement with AVX512, while on an Intel CPU you'll see some throttling and slow down if you mix AVX512 workload with AVX2 ones.
And the throttling and performance impact varies between different major Intel design versions. The current design performs quite a bit better with AVX512 than the first round of CPUs did.

Quote:
Zen4 basically runs AVX512 on AVX2 platform, but since some AVX512 instructions are more efficient than their plain AVX2 equivalent, speed sees some improvement.
Intel CPUs runs AVX512 natively, so they do get great improvement. However Intel CPU has that infamous clock throttling so it clocks lower, impacting normal workloads.
Yeah, even if it is the same fused instruction under the hood, AVX512 has smaller instruction size per bit, and so can stay in L3 cache better.

Quote:
It'll end up being a personal preference. AVX10 is a new thing and will take time to adopt. And AVX10 is, well, to just put "AVX512" back to existing product line.
Has anyone checked the x265 source code to see if many non-AVX10 instructions are being used? I wouldn't be surprised if the AVX10 subset includes most or all of what x265 uses. Video encoding is made of pretty well understood DSP algorithms, and ones that have broad applicability to things like gaming. So I'd expect them to have better odds of making it to a more consumer-focused AVX512 subset.
__________________
Ben Waggoner
Principal Video Specialist, Amazon Prime Video

My Compression Book
benwaggoner is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT +1. The time now is 12:08.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.