Arch Linux Developers Discuss Idea Of Providing An x86-64-v3 Port

[AmericanLocomotive]

10%-20% are NOT "modest" gains. They are the equivalent of a generation upgrade or two.

Exactly. 10-20% is a huge gain in performance these days. AMD and Intel would KILL if they could just "find" a free extra 10-20% performance.

Not just Intel. AMD also makes entry-level processors without AVX.

This is getting ridiculous. The goal is to make distributions more modern by catering to newer processors, and yet new entry-level processors released less than 18 months ago get shafted from these 'modern' distributions just because they lack AVX.

But is it always necessary to cater to the lowest common denominator? Does anyone have any sales numbers or market share breakdown of Intel's CPUs? Just how many non-chromebook Pentium Gold and Celerons are out there?

Maybe if there were some actual software pressure to require these instruction sets, Intel might reconsider constantly releasing CPUs with critical instructions missing? FWIW: All AMD CPUs since 2012 or so have had AVX. Even the A8-7680 mentioned earlier can do AVX2.

[Sonadow]

But is it always necessary to cater to the lowest common denominator?

Sit down and think carefully just how ridiculous this question is. When Microsoft or Apple drops CPUs from their list of supported hardware, the world rages but a desktop Linux distribution gets a free pass? What happened to the ridiculous boast of desktop Linux having superior out-of-the-box hardware compatibility than Windows?

So distribution maintainers get decide that they have the right to stop me from using their distribution just because i have a two year old Apollo Lake and Gemini Lake laptop that does not come with AVX?

Users with new hardware have every right to assume that their hardware will work on the latest x64-v3 optimized distribution, regardless of whether it's an Atom, Pentium or Celeron. Especially if the hardware is less than a year old.

You also conveniently forget the the only fanless laptops available today are powered by Atoms, Celerons and Pentiums. So a user who has a preference for fanless laptops gets unilaterally kicked out by various distribution minatainers just because they want to pursue instruction elitism by focusing on x64-v3?

[stiiixy]

Sit down and think carefully just how ridiculous this question is. When Microsoft or Apple drops CPUs from their list of supported hardware, the world rages but a desktop Linux distribution gets a free pass? What happened to the ridiculous boast of desktop Linux having superior out-of-the-box hardware compatibility than Windows?

So distribution maintainers get decide that they have the right to stop me from using their distribution just because i have a two year old Apollo Lake and Gemini Lake laptop that does not come with AVX?

Users with new hardware have every right to assume that their hardware will work on the latest x64-v3 optimized distribution, regardless of whether it's an Atom, Pentium or Celeron. Especially if the hardware is less than a year old.

You also conveniently forget the the only fanless laptops available today are powered by Atoms, Celerons and Pentiums. So a user who has a preference for fanless laptops gets unilaterally kicked out by various distribution minatainers just because they want to pursue instruction elitism by focusing on x64-v3?

It's Arch. It's MEANT to be for later hardware. Yes, there needs to be a shorter support life-span if older tech is holding back the newer from being capitalised upon. I want my money's worth of performance. I fully expect my older hardware to eventually disappear in favour of my newer machine on Arch! For your older hardware, well, this is the open-source world; choose a distro, any distro!

This is a Arch-linux specific thread, even if it's an industry-wide question being asked. For Arch, to me the answer is blindingly obvious; YES! But how to progress, well, I can proffer my two cents in the form of two versions:

- V4 (okay, 3.5 ahah!) Get on board with the latest, and remove the oldest and most irrelevant. Like GRUB mentioned in another thread. Basically a minefield of testing and critical bug-fixing for the future
- V2/'current' that will support V2 'soon' to help migrate OFF the platform if need be in a reasonable time-frame. Can easily benefit from V4 bug-fixes.

A six-month 'audit'/'survey conducted by Arch to determine where their software is being utilised would be a good start. Arch is not an LTS distro, it's a bleeding edge. A little common sense applies.

[fafreeman]

v4 is kinda ridiculous as it needs avx-512. iirc, only a few xeon versions even support avx-512. v3 would be ok. haswell like is 2014-ish. that's seven years ago. most people on ivy and below have been moving off. i understand that you cannot devote to the lowest common denominator. they're not the rule, rather they are an exception.

i really don't see a problem considering arch isn't a monoply on linux. other distros like debian won't be axing off plain x86-64v1 support. linux as a whole isn't like microsoft. even though some distros would love to dominate like microsoft, it isn't. we still have choices in distros with no one in particular being the one ring to rule them all.

[Sonadow]

It's Arch. It's MEANT to be for later hardware. Yes, there needs to be a shorter support life-span if older tech is holding back the newer from being capitalised upon. I want my money's worth of performance. I fully expect my older hardware to eventually disappear in favour of my newer machine on Arch! For your older hardware, well, this is the open-source world; choose a distro, any distro!

This is a Arch-linux specific thread, even if it's an industry-wide question being asked. For Arch, to me the answer is blindingly obvious; YES! But how to progress, well, I can proffer my two cents in the form of two versions:

- V4 (okay, 3.5 ahah!) Get on board with the latest, and remove the oldest and most irrelevant. Like GRUB mentioned in another thread. Basically a minefield of testing and critical bug-fixing for the future
- V2/'current' that will support V2 'soon' to help migrate OFF the platform if need be in a reasonable time-frame. Can easily benefit from V4 bug-fixes.

A six-month 'audit'/'survey conducted by Arch to determine where their software is being utilised would be a good start. Arch is not an LTS distro, it's a bleeding edge. A little common sense applies.

Did you even read my damned post, or just chose to jump straight with a reply?

The issue is not about old hardware. It's about brand new hardware literally released less than two months ago that cannot boot and use a distribution optimized for x64-v3 because they lack AVX.

How will you like it if Arch suddenly decided that they will optimize the distribution for x64-v4 and cut out all consumer processors, limiting its use only to Xeons Golds and Epycs? You going to sink upwards of $7k to build a new machine capable of AVX-512 just to continue using Arch?

[smitty3268]

Did you even read my damned post, or just chose to jump straight with a reply?

The issue is not about old hardware. It's about brand new hardware literally released less than two months ago that cannot boot and use a distribution optimized for x64-v3 because they lack AVX.

How will you like it if Arch suddenly decided that they will optimize the distribution for x64-v4 and cut out all consumer processors, limiting its use only to Xeons Golds and Epycs? You going to sink upwards of $7k to build a new machine capable of AVX-512 just to continue using Arch?

Did you read the article? Arch isn't cutting off non-AVX hardware, they are just going to have 2 versions. One for old hardware, and one for modern hardware.

Anyway, if every linux distro has to provide everything for everyone and do it well, then it's kind of silly to even have distros. We should all just use the same thing. Linux's biggest strength (and also weakness) is that every distro is free to go off and specialize at whatever they feel like. If they want to limit themselves to people with higher-end hardware then that would be fine by me. If that didn't work well for you anymore, it'd be high time to find a better distro that does suit you.

[lowflyer]

I'm not *that* familiar with the x86 processors, maybe somebody can explain this to me. Isn't there a way to emulate these newer instructions on older hardware? Something like a "unimplemented opcode exception". This used to be standard on the now legacy MC68000 series processors.

This would allow the older processors to work with newer code and completely obsolete that silly v2 v3 v4 discussion.

[ms178]

The issue is not about old hardware. It's about brand new hardware literally released less than two months ago that cannot boot and use a distribution optimized for x64-v3 because they lack AVX.

How will you like it if Arch suddenly decided that they will optimize the distribution for x64-v4 and cut out all consumer processors, limiting its use only to Xeons Golds and Epycs? You going to sink upwards of $7k to build a new machine capable of AVX-512 just to continue using Arch?

Sorry, but people who bought CPUs without AVX support in 2020 made a bad buying decision. ISA support matters, the new feature levels show it and there were AMD alternatives on the market to these Pentiums which had AVX support.

And your AVX-512 argument is absurd, as the market penetration of AVX-512 capable hardware is simply not there while AVX2 is widespread and common these days. Also as Smitty said, there is still the base variant for people who don't own capable hardware, so I don't really know what all the fuss is about. At least Arch is trying to accomodate to both users of legacy CPUs and capable hardware.

[Mat2]

10 year old PCs are Nehalem based, and are honestly getting pretty pokey these days, especially the mobile parts. My i7-2630qm laptop (which was a solid mid-pack quad-core mobile Sandy Bridge part in 2011) isn't the fastest on a lot of modern websites or even HD video playback, and it has an SSD. Even 2009 era pre-Nehalem Core CPUs are barely tolerable for general web browsing, with the lowest end Celeron chromebook chips offering similar or better performance.

Well, I have different experiences with older CPUs: they are still perfectly capable for web browsing. Maybe we browse different websites. Historically, one of the strengths of Linux has been that it runs well on older systems. It is relatively easy for us because almost all drivers are open source so we don't rely on vendor support. Back in time, when Windows XP was EOLed, many computers were converted to Linux.

AFAIK, all x86_64_v3 systems are UEFI.

Many servers still use legacy BIOS, this applies to most virtual machines. AWS EC2 instances with amd64 use legacy BIOS. Dropping support for them would be a large deal for server distributions like Ubuntu.
AFAIK, systemd-boot stores kernels and initrds on EFI System Partition, which is frequently way too small for this purpose. Increasing size of ESP is not straightforward with Windows installs.

[StanGenchev]

Because it's 10 years old now?

As I have said (and a few others) the AVX instruction set extension may be 10 years old but there are brand new CPUs without AVX support. AMD seems to be phasing out all non-AVX capable CPUs in their inventory but Intel still treats AVX as a premium feature and will most likely continue to do so. Yes, the majority of these CPUs are Pentium/Celeron/A8/A10 based but a lot of companies are buying PCs with such CPUs inside (the place that I work at did buy quite a few non-AVX capable laptops recently). It just seems odd to me that big corporations want to shoot themselves in the leg like that, although we have yet to see anyone make AVX a minimum requirement (with the exception of Clear Linux).

Personally, I think it would be a better choice to set the minimum requirements to something that is common in all x86 CPUs from the last 8-10 years.