Optimize Nix build CPU utilization with NIX_MAX_CORES#141266
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Artturin wants to merge 2 commits intoNixOS:stagingfrom
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Optimize Nix build CPU utilization with NIX_MAX_CORES#141266Artturin wants to merge 2 commits intoNixOS:stagingfrom
Artturin wants to merge 2 commits intoNixOS:stagingfrom
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6.topic: stdenv
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I don't understand why use both |
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forgot to remove it |
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10.rebuild-darwin-stdenv
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10.rebuild-darwin: 501+
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Does this need a doc update? |
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Author
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im using this script to test the logic #!/usr/bin/env bash
# Guess the optimal parallelism using the same formula as Ninja; return nothing
# if it can not be determined. (Note that "make" ignores "-l" without value.)
guessParallelism() {
local n
n=$(getconf _NPROCESSORS_ONLN 2>/dev/null || nproc 2>/dev/null || true)
#local n=1
if [ "$n" -ge 1 ]; then
if [ "$n" -le 2 ]; then
echo $((n+1))
else
echo $((n+2))
fi
fi
}
# NIX_MAX_CORES is the optimal load average (when known).
: "${NIX_MAX_CORES=$(guessParallelism)}"
echo $NIX_MAX_CORES
# Normalize the NIX_BUILD_CORES variable. The value might be 0, which
# means that we're supposed to try and auto-detect the number of
# available CPU cores at run-time.
NIX_BUILD_CORES=0
#NIX_BUILD_CORES=1
NIX_BUILD_CORES="${NIX_BUILD_CORES:-1}"
if ((NIX_BUILD_CORES <= 0)); then
((NIX_BUILD_CORES = NIX_MAX_CORES <= 0 ? 1 : NIX_MAX_CORES))
fi
echo NIX_MAX_CORES $NIX_MAX_CORES
echo NIX_BUILD_CORES $NIX_BUILD_CORES |
When `build-cores` is less than the number of CPUs, `make -l$NIX_BUILD_CORES` keeps the remaining CPUs unutilized even when `max-jobs` is greater than 1. This is good if you want to dedicate those CPUs to something other than Nix builds, and it is bad if you want to balance `build-cores` with `max-jobs` to maximize utilization of the system without overloading it. To achieve the latter goal `make -l` should be given the optimal load average which is now available in `$NIX_MAX_CORES`. The implementation mirrors Ninja: https://github.com/ninja-build/ninja/blob/e234a7bd/src/ninja.cc#L222-L233 https://github.com/ninja-build/ninja/blob/e234a7bd/src/util.cc#L473-L481 Co-authored-by: Orivej Desh <[email protected]>
Co-authored-by: Orivej Desh <[email protected]>
8 tasks
Contributor
|
if only we could make this configurable like max-cores 🙁 |
Member
Author
|
feel free to adopt this pr |
21 tasks
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READ #31965
When
build-coresis less than the number of CPUs,make -l$NIX_BUILD_CORESkeeps the remaining CPUs unutilized even when
max-jobsis greater than 1.This is good if you want to dedicate those CPUs to something other than Nix
builds, and it is bad if you want to balance
build-coreswithmax-jobstomaximize utilization of the system without overloading it. To achieve the latter
goal
make -lshould be given the optimal load average which is now availablein
$NIX_MAX_CORES.The implementation mirrors Ninja:
https://github.com/ninja-build/ninja/blob/e234a7bd/src/ninja.cc#L222-L233
https://github.com/ninja-build/ninja/blob/e234a7bd/src/util.cc#L473-L481
Motivation for this change
Rebased #31965, closes #31965
Things done
sandbox = trueset innix.conf? (See Nix manual)nix-shell -p nixpkgs-review --run "nixpkgs-review wip"./result/bin/)