Nix, the purely functional package manager
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Jade Lovelace 473d2d56fc Remove 100s of CPU time (10%) from build times (1465s -> 1302s)
Result's from Mic92's framework 13th Gen Intel Core i7-1360P:

Before: 3595.92s user 183.01s system 1360% cpu 4:37.74 total
After: 3486.07s user 168.93s system 1354% cpu 4:29.79 total

I saw that boost/lexical_cast was costing about 100s in CPU time on our
compiles. We can fix this trivially by doing explicit template
instantiation in exactly one place and eliminating all other includes of
it, which is a code improvement anyway by hiding the boost.

Before:
```
lix/lix2 » ClangBuildAnalyzer --analyze buildtimeold.bin
Analyzing build trace from 'buildtimeold.bin'...
**** Time summary:
Compilation (551 times):
  Parsing (frontend):         1465.3 s
  Codegen & opts (backend):   1110.9 s

<snip>

**** Expensive headers:
178153 ms: ../src/libcmd/installable-value.hh (included 52 times, avg 3426 ms), included via:
  40x: command.hh
  5x: command-installable-value.hh
  3x: installable-flake.hh
  2x: <direct include>
  2x: installable-attr-path.hh

176217 ms: ../src/libutil/error.hh (included 246 times, avg 716 ms), included via:
  36x: command.hh installable-value.hh installables.hh derived-path.hh config.hh experimental-features.hh
  12x: globals.hh config.hh experimental-features.hh
  11x: file-system.hh file-descriptor.hh
  6x: serialise.hh strings.hh
  6x: <direct include>
  6x: archive.hh serialise.hh strings.hh
  ...

173243 ms: ../src/libstore/store-api.hh (included 152 times, avg 1139 ms), included via:
  55x: <direct include>
  39x: command.hh installable-value.hh installables.hh
  7x: libexpr.hh
  4x: local-store.hh
  4x: command-installable-value.hh installable-value.hh installables.hh
  3x: binary-cache-store.hh
  ...

170482 ms: ../src/libutil/serialise.hh (included 201 times, avg 848 ms), included via:
  37x: command.hh installable-value.hh installables.hh built-path.hh realisation.hh hash.hh
  14x: store-api.hh nar-info.hh hash.hh
  11x: <direct include>
  7x: primops.hh eval.hh attr-set.hh nixexpr.hh value.hh source-path.hh archive.hh
  7x: libexpr.hh value.hh source-path.hh archive.hh
  6x: fetchers.hh hash.hh
  ...

169397 ms: ../src/libcmd/installables.hh (included 53 times, avg 3196 ms), included via:
  40x: command.hh installable-value.hh
  5x: command-installable-value.hh installable-value.hh
  3x: installable-flake.hh installable-value.hh
  2x: <direct include>
  1x: installable-derived-path.hh
  1x: installable-value.hh
  ...

159740 ms: ../src/libutil/strings.hh (included 221 times, avg 722 ms), included via:
  37x: command.hh installable-value.hh installables.hh built-path.hh realisation.hh hash.hh serialise.hh
  19x: <direct include>
  14x: store-api.hh nar-info.hh hash.hh serialise.hh
  11x: serialise.hh
  7x: primops.hh eval.hh attr-set.hh nixexpr.hh value.hh source-path.hh archive.hh serialise.hh
  7x: libexpr.hh value.hh source-path.hh archive.hh serialise.hh
  ...

156796 ms: ../src/libcmd/command.hh (included 51 times, avg 3074 ms), included via:
  42x: <direct include>
  7x: command-installable-value.hh
  2x: installable-attr-path.hh

150392 ms: ../src/libutil/types.hh (included 251 times, avg 599 ms), included via:
  36x: command.hh installable-value.hh installables.hh path.hh
  11x: file-system.hh
  10x: globals.hh
  6x: fetchers.hh
  6x: serialise.hh strings.hh error.hh
  5x: archive.hh
  ...

133101 ms: /nix/store/644b90j1vms44nr18yw3520pzkrg4dd1-boost-1.81.0-dev/include/boost/lexical_cast.hpp (included 226 times, avg 588 ms), included via
:
  37x: command.hh installable-value.hh installables.hh built-path.hh realisation.hh hash.hh serialise.hh strings.hh
  19x: file-system.hh
  11x: store-api.hh nar-info.hh hash.hh serialise.hh strings.hh
  7x: primops.hh eval.hh attr-set.hh nixexpr.hh value.hh source-path.hh archive.hh serialise.hh strings.hh
  7x: libexpr.hh value.hh source-path.hh archive.hh serialise.hh strings.hh
  6x: eval.hh attr-set.hh nixexpr.hh value.hh source-path.hh archive.hh serialise.hh strings.hh
  ...

132887 ms: /nix/store/h2abv2l8irqj942i5rq9wbrj42kbsh5y-gcc-12.3.0/include/c++/12.3.0/memory (included 262 times, avg 507 ms), included via:
  36x: command.hh installable-value.hh installables.hh path.hh types.hh ref.hh
  16x: gtest.h
  11x: file-system.hh types.hh ref.hh
  10x: globals.hh types.hh ref.hh
  10x: json.hpp
  6x: serialise.hh
  ...

  done in 0.6s.
```

After:
```
lix/lix2 » maintainers/buildtime_report.sh build
Processing all files and saving to '/home/jade/lix/lix2/maintainers/../buildtime.bin'...
  done in 0.6s. Run 'ClangBuildAnalyzer --analyze /home/jade/lix/lix2/maintainers/../buildtime.bin' to analyze it.
Analyzing build trace from '/home/jade/lix/lix2/maintainers/../buildtime.bin'...
**** Time summary:
Compilation (551 times):
  Parsing (frontend):         1302.1 s
  Codegen & opts (backend):    956.3 s

<snip>

**** Expensive headers:
178145 ms: ../src/libutil/error.hh (included 246 times, avg 724 ms), included via:
  36x: command.hh installable-value.hh installables.hh derived-path.hh config.hh experimental-features.hh
  12x: globals.hh config.hh experimental-features.hh
  11x: file-system.hh file-descriptor.hh
  6x: <direct include>
  6x: serialise.hh strings.hh
  6x: fetchers.hh hash.hh serialise.hh strings.hh
  ...

154043 ms: ../src/libcmd/installable-value.hh (included 52 times, avg 2962 ms), included via:
  40x: command.hh
  5x: command-installable-value.hh
  3x: installable-flake.hh
  2x: <direct include>
  2x: installable-attr-path.hh

153593 ms: ../src/libstore/store-api.hh (included 152 times, avg 1010 ms), included via:
  55x: <direct include>
  39x: command.hh installable-value.hh installables.hh
  7x: libexpr.hh
  4x: local-store.hh
  4x: command-installable-value.hh installable-value.hh installables.hh
  3x: binary-cache-store.hh
  ...

149948 ms: ../src/libutil/types.hh (included 251 times, avg 597 ms), included via:
  36x: command.hh installable-value.hh installables.hh path.hh
  11x: file-system.hh
  10x: globals.hh
  6x: fetchers.hh
  6x: serialise.hh strings.hh error.hh
  5x: archive.hh
  ...

144560 ms: ../src/libcmd/installables.hh (included 53 times, avg 2727 ms), included via:
  40x: command.hh installable-value.hh
  5x: command-installable-value.hh installable-value.hh
  3x: installable-flake.hh installable-value.hh
  2x: <direct include>
  1x: installable-value.hh
  1x: installable-derived-path.hh
  ...

136585 ms: ../src/libcmd/command.hh (included 51 times, avg 2678 ms), included via:
  42x: <direct include>
  7x: command-installable-value.hh
  2x: installable-attr-path.hh

133394 ms: /nix/store/h2abv2l8irqj942i5rq9wbrj42kbsh5y-gcc-12.3.0/include/c++/12.3.0/memory (included 262 times, avg 509 ms), included via:
  36x: command.hh installable-value.hh installables.hh path.hh types.hh ref.hh
  16x: gtest.h
  11x: file-system.hh types.hh ref.hh
  10x: globals.hh types.hh ref.hh
  10x: json.hpp
  6x: serialise.hh
  ...

89315 ms: ../src/libstore/derived-path.hh (included 178 times, avg 501 ms), included via:
  37x: command.hh installable-value.hh installables.hh
  25x: store-api.hh realisation.hh
  7x: primops.hh eval.hh attr-set.hh nixexpr.hh value.hh context.hh
  6x: eval.hh attr-set.hh nixexpr.hh value.hh context.hh
  6x: libexpr.hh value.hh context.hh
  6x: shared.hh
  ...

87347 ms: /nix/store/h2abv2l8irqj942i5rq9wbrj42kbsh5y-gcc-12.3.0/include/c++/12.3.0/ostream (included 273 times, avg 319 ms), included via:
  35x: command.hh installable-value.hh installables.hh path.hh types.hh ref.hh memory unique_ptr.h
  12x: regex sstream istream
  10x: file-system.hh types.hh ref.hh memory unique_ptr.h
  10x: gtest.h memory unique_ptr.h
  10x: globals.hh types.hh ref.hh memory unique_ptr.h
  6x: fetchers.hh types.hh ref.hh memory unique_ptr.h
  ...

85249 ms: ../src/libutil/config.hh (included 213 times, avg 400 ms), included via:
  37x: command.hh installable-value.hh installables.hh derived-path.hh
  20x: globals.hh
  20x: logging.hh
  16x: store-api.hh logging.hh
  6x: <direct include>
  6x: eval.hh attr-set.hh nixexpr.hh value.hh context.hh derived-path.hh
  ...

  done in 0.5s.
```

Adapated from 18aa3e1d57
2024-05-31 13:00:09 +02:00
.github Bump zeebe-io/backport-action from 2.5.0 to 3.0.2 2024-05-28 13:10:48 +00:00
config Remove and gitignore the autoreconf generated files 2024-03-02 10:18:47 +01:00
contrib function-trace: always show the trace 2019-09-18 23:23:21 +02:00
dep-patches Move dependency patches from top level into subdir 2024-01-17 13:13:54 -05:00
doc print type and value in "flake attr is not a derivation" errors 2024-05-29 20:51:32 +02:00
m4 Build a minimized Nix with MinGW 2024-04-17 12:26:10 -04:00
maintainers Merge pull request #10789 from nix-windows/windows-substitution-goal 2024-05-29 22:45:55 +02:00
misc Remove custom lowdown 2023-12-13 16:25:18 -05:00
mk Shellcheck some test scripts 2024-05-28 12:32:22 -04:00
perl Fix perl build 2024-05-06 20:00:44 +02:00
scripts Start getting all shell scripts passing shellcheck 2024-05-27 22:39:56 -04:00
src Remove 100s of CPU time (10%) from build times (1465s -> 1302s) 2024-05-31 13:00:09 +02:00
tests Ensure all functional scripts are (a) executable (b) have shebang 2024-05-28 12:46:24 -04:00
.clang-format Add StoreReference::render 2024-05-22 09:20:15 -04:00
.clang-tidy Add .clang-tidy 2024-02-01 01:01:39 +01:00
.dir-locals.el .dir-locals.el: Set c-block-comment-prefix 2020-07-10 11:21:06 +02:00
.editorconfig .editorconfig: Also affect Perl FFI xs file 2023-11-09 23:11:52 -05:00
.gitignore Shellcheck some test scripts 2024-05-28 12:32:22 -04:00
.shellcheckrc Start getting all shell scripts passing shellcheck 2024-05-27 22:39:56 -04:00
.version Bump version 2024-04-23 14:14:13 +02:00
CITATION.cff chore: PhD thesis as reference in CITATION.cff 2024-05-18 20:05:22 +02:00
configure.ac Use CFLAGS for libseccomp from pkg-config also for the CFLAGS 2024-05-21 00:52:11 +02:00
CONTRIBUTING.md add a recommendation for first-time contributors (#10605) 2024-04-25 13:34:15 +02:00
COPYING * Change this to LGPL to keep the government happy. 2006-04-25 16:41:06 +00:00
default.nix add flake-compat to flake.nix and use sha256 in default.nix 2023-03-06 21:11:24 +01:00
docker.nix fix "add an option to include flake-registry..." 2023-05-16 14:35:31 +02:00
flake.lock Add pre-commit hook and make format target 2024-04-21 13:54:34 +02:00
flake.nix Add repl completion test 2024-05-27 09:58:49 +02:00
local.mk local.mk: Solve warnings 2024-04-17 15:37:14 +02:00
Makefile add and fix -Wignored-qualifiers 2024-05-17 19:29:50 +02:00
Makefile.config.in C API: fix docs build after rebase 2024-03-28 10:51:59 +01:00
package.nix Move libseccomp source override outside package.nix 2024-04-25 16:38:35 -04:00
precompiled-headers.h Build a minimized Nix with MinGW 2024-04-17 12:26:10 -04:00
README.md fix: Remove extra to from README.md (#9213) 2023-10-23 19:20:23 +02:00
shell.nix Remove url literals 2022-01-24 13:28:21 +01:00

Nix

Open Collective supporters Test

Nix is a powerful package manager for Linux and other Unix systems that makes package management reliable and reproducible. Please refer to the Nix manual for more details.

Installation and first steps

Visit nix.dev for installation instructions and beginner tutorials.

Full reference documentation can be found in the Nix manual.

Building And Developing

See our Hacking guide in our manual for instruction on how to set up a development environment and build Nix from source.

Contributing

Check the contributing guide if you want to get involved with developing Nix.

Additional Resources

License

Nix is released under the LGPL v2.1.