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robert.zaremba

Member

Registered: 2025-01-08

Posts: 2

What is the x86-64 microarchitecture level?

I saw that the RFC-002 "Provide a x86-64-v3 microarchitecture level port" was merged.
Are x86-64 packages build with v2 or v3 level? Is there any plan for that?

Last edited by robert.zaremba (2025-01-08 10:26:19)

V1del

Forum Moderator

Registered: 2012-10-16

Posts: 23,731

Re: What is the x86-64 microarchitecture level?

If you read the actual RFC all of these questions would be answered.

The current "baseline" is without any level -- so whatever x86-64 originally specified 20 years ago. The purpose of this RFC (or rather, the implementation that is planned to happen) is to provide v3 for capable HW (mostly the stuff that supports AVX2 instructions) so raises the "CPU bar" to ~2016 for optimized binaries, as well as the normal x86-64 packages that are already provided.

If you're asking whether any of this is already implemented - not yet, no.

Also note this only affects tools that don't have custom code paths to make use of newer instructions if available and relying on what GCC can optimize automatically. Tools that already have custom runtime detection of newer instruction sets will already be using newer instructions as they are available (e.g. stuff like ffmpeg or blender or so, will already make use of newer instruction sets if available because they have explicit code for it)

Last edited by V1del (2025-01-08 11:25:30)

robert.zaremba

Member

Registered: 2025-01-08

Posts: 2

Re: What is the x86-64 microarchitecture level?

Thanks for the reply. The RFC is from 2020, so I wondered if anything changed 'now'.

V1del

Forum Moderator

Registered: 2012-10-16

Posts: 23,731

Re: What is the x86-64 microarchitecture level?

If you're asking whether any of this is already implemented - not yet, no.

That the RFC got accepted just means that people are in agreement that it makes sense to do this at some point, when this actually happens depends on available time and tooling (there's been quite a few things going into that direction with the proper move to git and the new pkgctl tools) but as far as I know, no actual work has yet been done to really implement this.

There's an unofficial repo implementing the relevant rebuilds: https://wiki.archlinux.org/title/Unoffi … ories#ALHP -- use at your own risk and explicitly mention - and don't expect support for - the fact you're using this should you opt for it and need assistance here.

Last edited by V1del (2025-01-08 14:08:54)