impureUseNativeOptimizations: add stdenv adapter #37600
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Just wondering--do you need to build all dependencies this way too? If not, a trick I've used in the past is to build a variants with different architecture assumptions (supported vector instructions, etc.). Not always possible and possibly more of a hassle but it does retain Nix purity :). |
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@dtzWill No, I don't -- all the hotpath is in the emulator. I'm not sure how much of that optimization comes from specific instructions and how much from |
pkgs/stdenv/adapters.nix
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| NIX_CFLAGS_COMPILE = toString (args.NIX_CFLAGS_COMPILE or "") + " -march=native"; | ||
| NIX_ENFORCE_NO_NATIVE = false; | ||
| }); | ||
| }; |
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preferLocalBuild = true; seems to be appropriate.
This allows one to force a compiler to use native machine optimizations. This goes contrary to all the usual guarantees of Nix and so should be used only by end-user and only in specific cases when they know what are they doing. In my case this is needed to get a noticeable FPS boost in RPCS3 which is very CPU-hungry PlayStation 3 emulator.
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ping |
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I'd like to merge this in the following few days unless anyone minds. |
Motivation for this change
This allows one to force a compiler to use native machine optimizations. This
goes contrary to all the usual guarantees of Nix and so should be used only by
end-user and only in specific cases when they know what are they doing.
In my case this is needed to get a noticeable FPS boost in RPCS3 which is a very
CPU-hungry PlayStation 3 emulator.
I'm torn on whether to have this in upstream nixpkgs, hence PR.
Things done
build-use-sandboxinnix.confon non-NixOS)nix-shell -p nox --run "nox-review wip"./result/bin/)