CentOS ISA SIG Experimenting With New x86-64 Baseline For Better Performance

[phoronix]

Phoronix: CentOS ISA SIG Experimenting With New x86-64 Baseline For Better Performance

The CentOS ISA special interest group (SIG) has been evaluating the performance of CentOS Stream in the event its x86_64 baseline were to be raised from x86-64-v2 to x86-64-v3. Currently CentOS Stream 9 targets x86-64-v2 but in upping the support requirements to x86-64-v3, it would allow the ability to engage AVX/AVX2 by default and make use of other newer instruction set features. The x86-64-v3 baseline roughly correlates to Intel / AMD CPUs from 2015 and newer...

https://www.phoronix.com/news/CentOS-ISA-Experiment-Perform

[You-]

I was worried that with RHEL10/Stream10 I would need to use a rebuilder to keep using my current server.

However I have checked and it supports x86-64v3 so I am good for another few years!

[coder]

The x86-64-v3 baseline roughly correlates to Intel / AMD CPUs from 2015 and newer.

Haswell launched in 2013. It's AMD that didn't have them until 2015 (Excavator).

If you have a Chromebook, mini-PC, or entry-level laptop with Jasper/Elkhart Lake or before, that's still at v2. Intel's E-cores didn't reach v3 until Alder Lake N finally launched, this year.

Now that glibc lets you ship multiple builds of a given library, with the best one supported by the host being loaded at runtime, and they note that relatively few libraries or packages seem to benefit from v3, let's hope the route they take is to ship multiple builds. In that case, they can even go up to v4, for those with machines supporting AVX-512.

[SofS]

Intel segmented AVX and AVX2 a lot. Celerons and Pentiums only got them in 2022 for instance (from families 6000 and 7000 respectively).

[ms178]

Intel segmented AVX and AVX2 a lot. Celerons and Pentiums only got them in 2022 for instance (from families 6000 and 7000 respectively).

... and one argument for these back then was: "AVX isn't needed nor widely required", sometimes together with "you don't need more than two cores anyway", it turns out AVX2 support *is* important now. These poor souls who could have bought an AMD CPU with support for these instructions instead are now left with less optimized binaries / distros to use. Fair enough, I'd say. That's how progress on the software side might teach these people to factor in to put more emphasize on these CPU features for their next purchase decision if long term value is a concern for them.

[JEBjames]

Michael

Typo "with these diffetent defaults." should be "with these different defaults."

[ms178]

What's next? I hope Valve will lead efforts to bring Steam games to x86-64-v3. Not only for new games but also for older titles. At least I assume that such a re-compile of older games with more recent compiler versions would be feasible without too much effort and might show some benefits (even if these came primarily from using a newer compiler version).

[gnattu]

What's next? I hope Valve will lead efforts to bring Steam games to x86-64-v3. Not only for new games but also for older titles. At least I assume that such a re-compile of older games with more recent compiler versions would be feasible without too much effort and might show some benefits (even if these came primarily from using a newer compiler version).

Actually lots of games require an x86-64 v3 CPU, and such requirement happened years ago. Why? Because of DRM! One of the most common use case of AVX in games nowadays, is the DRM mechanism shipping with the game. Unfortunately such common practice of AVX in gaming is making the game to run slower instead of faster.

[ms178]

Actually lots of games require an x86-64 v3 CPU, and such requirement happened years ago. Why? Because of DRM! One of the most common use case of AVX in games nowadays, is the DRM mechanism shipping with the game. Unfortunately such common practice of AVX in gaming is making the game to run slower instead of faster.

Hm, maybe I have missed that boat. I was on Westmere and Nehalem CPUs up until 2019 for a large part of the past decade, I never ran into issue with games mandating AVX. And if I remember correctly only a handful of games might have been AVX-only at that time. A quick search reveals some complaints of these Xeon users about more and more games demanding AVX, so it might be an entirely different picture today. Nevertheless, I haven't heard of much use inside of game engines yet apart from DRM. Or has that changed recently as well?

[edxposed]

What's next? I hope Valve will lead efforts to bring Steam games to x86-64-v3. Not only for new games but also for older titles. At least I assume that such a re-compile of older games with more recent compiler versions would be feasible without too much effort and might show some benefits (even if these came primarily from using a newer compiler version).

It's unlikely to happen, Steam's own client is also 32bit