nixpkgs/pkgs/os-specific/linux/trace-cmd/default.nix
Graham Christensen c2b898da76 treewide: drop -l$NIX_BUILD_CORES
Passing `-l$NIX_BUILD_CORES` improperly limits the overall system load.

For a build machine which is configured to run `$B` builds where each
build gets `total cores / B` cores (`$C`), passing `-l $C` to make will
improperly limit the load to `$C` instead of `$B * $C`.

This effect becomes quite pronounced on machines with 80 cores, with
40 simultaneous builds and a cores limit of 2. On a machine with this
configuration, Nix will run 40 builds and make will limit the overall
system load to approximately 2. A build machine with this many cores
can happily run with a load approaching 80.

A non-solution is to oversubscribe the machine, by picking a larger
`$C`. However, there is no way to divide the number of cores in a way
which fairly subdivides the available cores when `$B` is greater than
1.

There has been exploration of passing a jobserver in to the sandbox,
or sharing a jobserver between all the builds. This is one option, but
relatively complicated and only supports make. Lots of other software
uses its own implementation of `-j` and doesn't support either `-l` or
the Make jobserver.

For the case of an interactive user machine, the user should limit
overall system load using `$B`, `$C`, and optionally systemd's
cpu/network/io limiting features.

Making this change should significantly improve the utilization of our
build farm, and improve the throughput of Hydra.
2022-09-22 16:01:23 -04:00

64 lines
2 KiB
Nix

{ lib, stdenv, fetchgit, pkg-config, asciidoc, xmlto, docbook_xsl, docbook_xml_dtd_45, libxslt, libtraceevent, libtracefs, zstd, sourceHighlight }:
stdenv.mkDerivation rec {
pname = "trace-cmd";
version = "3.1.2";
src = fetchgit {
url = "git://git.kernel.org/pub/scm/utils/trace-cmd/trace-cmd.git/";
rev = "trace-cmd-v${version}";
sha256 = "sha256-wxrMEE7ZgMHM59Rv6Gk3f0zdpULuXLnY0UY797YF1a0=";
};
# Don't build and install html documentation
postPatch = ''
sed -i -e '/^all:/ s/html//' -e '/^install:/ s/install-html//' \
Documentation{,/trace-cmd,/libtracecmd}/Makefile
'';
nativeBuildInputs = [ asciidoc libxslt pkg-config xmlto docbook_xsl docbook_xml_dtd_45 sourceHighlight ];
buildInputs = [ libtraceevent libtracefs zstd ];
outputs = [ "out" "lib" "dev" "man" ];
MANPAGE_DOCBOOK_XSL="${docbook_xsl}/xml/xsl/docbook/manpages/docbook.xsl";
dontConfigure = true;
enableParallelBuilding = true;
makeFlags = [
# The following values appear in the generated .pc file
"prefix=${placeholder "lib"}"
];
# We do not mention targets (like "doc") explicitly in makeFlags
# because the Makefile would not print warnings about too old
# libraries (see "warning:" in the Makefile)
postBuild = ''
make libs doc -j$NIX_BUILD_CORES
'';
installTargets = [
"install_cmd"
"install_libs"
"install_doc"
];
installFlags = [
"LDCONFIG=false"
"bindir=${placeholder "out"}/bin"
"mandir=${placeholder "man"}/share/man"
"libdir=${placeholder "lib"}/lib"
"pkgconfig_dir=${placeholder "dev"}/lib/pkgconfig"
"includedir=${placeholder "dev"}/include"
"BASH_COMPLETE_DIR=${placeholder "out"}/share/bash-completion/completions"
];
meta = with lib; {
description = "User-space tools for the Linux kernel ftrace subsystem";
homepage = "https://www.trace-cmd.org/";
license = with licenses; [ lgpl21Only gpl2Only ];
platforms = platforms.linux;
maintainers = with maintainers; [ thoughtpolice basvandijk ];
};
}