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

While recently Arch Linux developers and stakeholders were discussing the possibility of raising the x86-64 base requirements for this Linux distribution to the "x86-64-v2" micro-architecture feature level that roughly correlates to Intel Nehalem and newer, now the discussion has shifted to keeping the same x86-64 base level while potentially offering a "x86-64-v3" port for those with newer Intel/AMD CPUs.

Rather than raising the Arch Linux x86 64-bit requirements to the "x86-64-v2" level that would yield issues for those trying to run this distribution on the oldest of original x86-64 AMD/Intel processors, the proposal has morphed into providing an x86-64-v3 port that would be maintained concurrently to base x86-64. With this, users running Arch on vintage PCs wouldn't lose out on updates while those on more recent hardware would be able to tap into more optimized packages by default.

The x86-64-v3 microarchitecture level roughy correlates to that of Intel Haswell era processors. The x86-64-v3 level enables AVX, AVX2, BMI2, MOVBE, XSAVE, and other instructions found on Intel and AMD processors of the past several years.

Those with Intel Haswell CPUs and newer could soon potentially tap into more optimized packages on Arch Linux. On the AMD side this corresponds to AMD Excavator and newer. But those with older CPUs would still be able to use the base x86-64 packages.

In large part to being able to assume Advanced Vector Extensions by default, going for x86-64-v3 allows for much greater performance advantages than say just setting a x86-64-v2 base where there its biggest benefit is SSE4.1/SSE4.2/SSSE3.

The prospects of an Arch Linux x86-64-v3 port are quite exciting. This is a good baseline for an alternative x86-64 port since the x86-64-v4 level is much more restrictive in needing AVX-512.

So the latest proposal in favoring an x86-64-v3 port over just setting an x86-64-v2 baseline is quite exciting. Some initial benchmarks on Arch show the performance advantages to x86-64-v3/Haswell targeting compared to base x86-64 or x86-64-v2. Let's hope this passes.

I'll also be out with some x86-64 microarchitecture feature level comparisons soon with the GCC 11.1 release. RHEL9 meanwhile is still planning to raise its requirements to x86-64-v2 CPUs.