4 ms·

That's what comes with actually using the instruction set of modern CPU's instead of the lowest common denominator instruction set. However, note that some of

That's what comes with actually using the instruction set of modern CPU's instead of the lowest common denominator instruction set. However, note that some of the modern instructions like AVX-512 use a lot of electrical power on the CPU, for example pushing a 12gen Intel chip above 300W.

Arrath 2y ago
> for example pushing a 12gen Intel chip above 300W And pushing 13th and 14th gen chips into an early grave! /s
- ElectricalUnion 2y ago
  Not really because AVX-512 isn't supported by those platforms; supposedly something related to processes in general being very unhappy if they're being scheduled to E cores that doesn't handle those instructions randomly.
luyu_wu 2y ago
An interesting part of Zen 5 architecture was related to lowering the absurd instruction passthrough time/power if I remember correctly! This definetly used to be the case on the older Intel implementations of large SIMD instructions (my Tiger lake chip being an anecdote)!
lathiat 2y ago
Ubuntu is experimenting with making a more modern CPU build: https://discourse.ubuntu.com/t/trying-out-ubuntu-23-04-on-x86-64-v3-rebuild-for-yourself/40963 https://discourse.ubuntu.com/t/trying-out-ubuntu-23-04-on-x8... https://www.phoronix.com/review/ubuntu-x86-64-v3-benchmark https://www.phoronix.com/review/ubuntu-x86-64-v3-benchmark Also -O3: https://www.phoronix.com/news/Ubuntu-Evaluating-O3-Optimized https://www.phoronix.com/news/Ubuntu-Evaluating-O3-Optimized I am not sure off hand how that CPU level compares to Intel Clear Linux's options. The phoronix comparison fo Ubuntu with and without v3 were mostly quite small single digit percent though, on an Intel CPU. Notes: Canonical (Ubuntu) is my employer, I am not working on this project.
- justinclift 2y ago
  Hmm, -O3 at least used to have a bad reputation for producing potentially buggy and/or slow code. That was years ago though, and I have no idea if that's changed for the better.
  - lathiat 2y ago
    I do solidly remember this from the "earlier" (200x) Gentoo days.
CoastalCoder 2y ago
This is what bothers me about the characterizations of CPU architecture in ELF files and (IIRC) Python eggs... They're so vague about which particular x86 ISA variants are compatible with the binaries. So, e.g., a program loader doesn't necessarily verify that the binary will work on the CPU. Or, as we see with Linux distros, they build packages for the lowest common denominator ISA. (Note: it's been a while since I dealt with this, so I might be remembering a bit wrong.)
Lockal 2y ago
I wouldn't write it all off on the AVX-512 in this case. As you can see in https://github.com/clearlinux-pkgs/php https://github.com/clearlinux-pkgs/php and other clearlinux repositories, the difference from other distros is: 1) a number of backported optimization patches 2) few patches in Linux kernel and glibc that were not accepted to upstream 3) and maybe the most important part: PGO for python, php and other performance-critical components. It is a well-known fact that PGO helps interpreted languages. And it is benchmark-oriented: for example, even though PGO helps bash, they don't enable it (maybe until somebody invents bash-bench).
- paulryanrogers 2y ago
  Does benchmark-oriented means it's unlikely to help (or could even hurt) real world applications?
  - Lockal 2y ago
    ClearLinux pulls phpbench-0.8.2 (and no other applications) for PGO[1] and then Phoronix benchmarks with phpbench-0.8.1. In my opinion, that's a valid reason to disqualify the result. It does not mean that PGO makes PHP faster or slower, it means that there are no measurements to make the conclusion. I only have theory, that PGO generally helps to reduce startup time, so that in case when app starts 1000s times per second, it helps even if PGO data is irrelevant. But modern PHP does not behave in this way, also some real-word PHP apps are usually CPU / I/O bound in database, so one may see no difference... Some time ago I tried to apply PGO to Blender, which only hurt the performance, but that's the other story (I read it as: if application already has logical separation for kernels for CPUs, attempt to join and reseparate in PGO may hurt the performance). [1] https://github.com/clearlinux-pkgs/php/blob/03c0859388a5d64011d85b15f4d9ccb02f2c2a43/php.spec#L15C12-L15C82 https://github.com/clearlinux-pkgs/php/blob/03c0859388a5d640...

Arrath 2y ago

> for example pushing a 12gen Intel chip above 300W And pushing 13th and 14th gen chips into an early grave! /s

ElectricalUnion 2y ago
Not really because AVX-512 isn't supported by those platforms; supposedly something related to processes in general being very unhappy if they're being scheduled to E cores that doesn't handle those instructions randomly.

luyu_wu 2y ago

An interesting part of Zen 5 architecture was related to lowering the absurd instruction passthrough time/power if I remember correctly! This definetly used to be the case on the older Intel implementations of large SIMD instructions (my Tiger lake chip being an anecdote)!

lathiat 2y ago

Ubuntu is experimenting with making a more modern CPU build: https://discourse.ubuntu.com/t/trying-out-ubuntu-23-04-on-x86-64-v3-rebuild-for-yourself/40963 https://discourse.ubuntu.com/t/trying-out-ubuntu-23-04-on-x8... https://www.phoronix.com/review/ubuntu-x86-64-v3-benchmark https://www.phoronix.com/review/ubuntu-x86-64-v3-benchmark Also -O3: https://www.phoronix.com/news/Ubuntu-Evaluating-O3-Optimized https://www.phoronix.com/news/Ubuntu-Evaluating-O3-Optimized I am not sure off hand how that CPU level compares to Intel Clear Linux's options. The phoronix comparison fo Ubuntu with and without v3 were mostly quite small single digit percent though, on an Intel CPU. Notes: Canonical (Ubuntu) is my employer, I am not working on this project.

justinclift 2y ago
Hmm, -O3 at least used to have a bad reputation for producing potentially buggy and/or slow code. That was years ago though, and I have no idea if that's changed for the better.
- lathiat 2y ago
  I do solidly remember this from the "earlier" (200x) Gentoo days.

CoastalCoder 2y ago

This is what bothers me about the characterizations of CPU architecture in ELF files and (IIRC) Python eggs... They're so vague about which particular x86 ISA variants are compatible with the binaries. So, e.g., a program loader doesn't necessarily verify that the binary will work on the CPU. Or, as we see with Linux distros, they build packages for the lowest common denominator ISA. (Note: it's been a while since I dealt with this, so I might be remembering a bit wrong.)

Lockal 2y ago

I wouldn't write it all off on the AVX-512 in this case. As you can see in https://github.com/clearlinux-pkgs/php https://github.com/clearlinux-pkgs/php and other clearlinux repositories, the difference from other distros is: 1) a number of backported optimization patches 2) few patches in Linux kernel and glibc that were not accepted to upstream 3) and maybe the most important part: PGO for python, php and other performance-critical components. It is a well-known fact that PGO helps interpreted languages. And it is benchmark-oriented: for example, even though PGO helps bash, they don't enable it (maybe until somebody invents bash-bench).

paulryanrogers 2y ago
Does benchmark-oriented means it's unlikely to help (or could even hurt) real world applications?
- Lockal 2y ago
  ClearLinux pulls phpbench-0.8.2 (and no other applications) for PGO[1] and then Phoronix benchmarks with phpbench-0.8.1. In my opinion, that's a valid reason to disqualify the result. It does not mean that PGO makes PHP faster or slower, it means that there are no measurements to make the conclusion. I only have theory, that PGO generally helps to reduce startup time, so that in case when app starts 1000s times per second, it helps even if PGO data is irrelevant. But modern PHP does not behave in this way, also some real-word PHP apps are usually CPU / I/O bound in database, so one may see no difference... Some time ago I tried to apply PGO to Blender, which only hurt the performance, but that's the other story (I read it as: if application already has logical separation for kernels for CPUs, attempt to join and reseparate in PGO may hurt the performance). [1] https://github.com/clearlinux-pkgs/php/blob/03c0859388a5d64011d85b15f4d9ccb02f2c2a43/php.spec#L15C12-L15C82 https://github.com/clearlinux-pkgs/php/blob/03c0859388a5d640...