lix/src/libutil/compute-levels.hh

#pragma once
///@file

#include "types.hh"

namespace nix {

StringSet computeLevels();

}
Ensure all headers have `#pragma once` and are in API docs `///@file` makes them show up in the internal API dos. A tiny few were missing `#pragma once`. 2023-04-01 03:18:41 +00:00			`#pragma once`
			`///@file`

Add x86_64 compute levels as additional system types When performing distributed builds of machine learning packages, it would be nice if builders without the required SIMD instructions can be excluded as build nodes. Since x86_64 has accumulated a large number of different instruction set extensions, listing all possible extensions would be unwieldy. AMD, Intel, Red Hat, and SUSE have recently defined four different microarchitecture levels that are now part of the x86-64 psABI supplement and will be used in glibc 2.33: https://gitlab.com/x86-psABIs/x86-64-ABI https://lwn.net/Articles/844831/ This change uses libcpuid to detect CPU features and then uses them to add the supported x86_64 levels to the additional system types. For example on a Ryzen 3700X: $ ~/aps/bin/nix -vv --version \| grep "Additional system" Additional system types: i686-linux, x86_64-v1-linux, x86_64-v2-linux, x86_64-v3-linux 2021-02-16 13:32:12 +00:00			`#include "types.hh"`

			`namespace nix {`

			`StringSet computeLevels();`

			`}`