RPM Lands Support For x86_64 Microarchitecture Feature Levels

[phoronix]

Phoronix: RPM Lands Support For x86_64 Microarchitecture Feature Levels

The RPM package manager code has added support for the x86_64 micro-architecture feature levels that allow for newer baseline targets than conventional x86_64. This support in RPM allows for installing RPMs built for newer feature levels on capable hardware...

https://www.phoronix.com/news/RPM-x86_64-Feature-Levels

[GunpowderGuy]

Will this allow packages without cpu security mitigations suited for recent cpus that dont need them?

[jorgepl]

Nice! How do other distros manage this? Or is RPM just late to the party?

[TemplarGR]

It is about time... Basic x64 is almost 20 years old. 20 freaking years.... Modern bleeding edge distros need to upgrade to at least v2. Anyone with that old hardware can keep using older distros, or use distros tailored to basic x64 machines.

[yump]

It's not entirely about old hardware (although v2 would exclude AMD Phenom II processors that were contemporary with Sandy Bridge and still reasonably capable). Intel was still making Pentiums that didn't support v3 as of like, 2020. Also the earlier chips with AVX2 (v3) have similar voltage/frequency license behavior to the much-discussed AVX-512 Skylakes, where any process on the system using wide SIMD incurs a (probably 20 us) hiccup for every process on the system, as well as a frequency reduction if that hasn't been disabled in the firmware overclocking settings.

That said, v2 is pretty widely compatible and would probably be a secular improvement, and I expect that the entire point of this work is to allow distributions to provide multiple package variants and not break compatibility with old hardware.

[brucethemoose]

Nice! How do other distros manage this? Or is RPM just late to the party?

Pacman (Arch) handles it, but you have to use unofficial repos (namely CachyOS or ALHP) to take advantage of it for now. Cachyos has V3 and V4 packages, ALHP has V3 only I think, base Arch is still not using it and I have no idea what is blocking it.

Clear Linux has many levels supported by swupd.

... maybe Solaris also does this? Other than that, I'm not aware of other distros shipping different architecture levels.

[brucethemoose]

Also the earlier chips with AVX2 (v3) have similar voltage/frequency license behavior to the much-discussed AVX-512 Skylakes, where any process on the system using wide SIMD incurs a (probably 20 us) hiccup for every process on the system, as well as a frequency reduction if that hasn't been disabled in the firmware overclocking settings.

You're talking about Haswell? I still have a haswell desktop CPU kicking, and its not quite like the Skylake AVX512 situation.

Whenever they hit an AVX2 workload, the haswell desktop CPUs kick their voltage up... unless you set your motherboard to use a static voltage. Its kinda complicated, but basically I'm not aware of any frequency regression, just somewhat higher voltages and temps, and it doesn't seem to be as sensitive as Skylake AVX512, which reportedly downclock if the cores so much as *sniff* an AVX512 instruction.

[GunpowderGuy]

Pacman (Arch) handles it, but you have to use unofficial repos (namely CachyOS or ALHP) to take advantage of it for now. Cachyos has V3 and V4 packages, ALHP has V3 only I think, base Arch is still not using it and I have no idea what is blocking it.

Clear Linux has many levels supported by swupd.

... maybe Solaris also does this? Other than that, I'm not aware of other distros shipping different architecture levels.

ALHP is an unofficial repo for arch but CachyOS is an arch based distro right?

[ezst036]

It is about time... Basic x64 is almost 20 years old. 20 freaking years....

That's not a long time. Why aren't you using Windows (or a Mac) if this is your attitude? If you want to go get cut off, you can have it and you can have it right now. Leave other people out of it.

[yump]

You're talking about Haswell? I still have a haswell desktop CPU kicking, and its not quite like the Skylake AVX512 situation.

Whenever they hit an AVX2 workload, the haswell desktop CPUs kick their voltage up... unless you set your motherboard to use a static voltage. Its kinda complicated, but basically I'm not aware of any frequency regression, just somewhat higher voltages and temps, and it doesn't seem to be as sensitive as Skylake AVX512, which reportedly downclock if the cores so much as *sniff* an AVX512 instruction.

Yeah, I was mistaken. AVX (frequency) offset was apparently introduced in Skylake, and the FIVR is damn fast:

The high bandwidth also enables fast voltage transitions. A FIVR rail turning on and turning off are shown in Fig. 7. Both transitions are programmed to about half a microsecond for a full range transition – two orders of magnitude faster than a typical platform-based solution.

Sadly, my 4670K seemingly doesn't actually use the ability to run the cores at different frequencies.