pennae
8168a4cf4a
with position and symbol tables in place we can now shrink Attr by a full
pointer with some simple field reordering. since Attr is a very hot struct this
has substantial impact on memory use, decreasing GC allocations and heap size by
10-15% each. we also get a ~15% performance improvement due to reduced GC
loading.
pure parsing has taken a hit over the branch base because positions are now
slightly more expensive to create, but overall we get a noticeable improvement.
before (on memory-friendliness):
Benchmark 1: nix search --no-eval-cache --offline ../nixpkgs hello
Time (mean ± σ): 6.960 s ± 0.028 s [User: 5.832 s, System: 0.897 s]
Range (min … max): 6.886 s … 7.005 s 20 runs
Benchmark 2: nix eval -f ../nixpkgs/pkgs/development/haskell-modules/hackage-packages.nix
Time (mean ± σ): 328.1 ms ± 1.7 ms [User: 295.8 ms, System: 32.2 ms]
Range (min … max): 324.9 ms … 331.2 ms 20 runs
Benchmark 3: nix eval --raw --impure --expr 'with import <nixpkgs/nixos> {}; system'
Time (mean ± σ): 2.688 s ± 0.029 s [User: 2.365 s, System: 0.238 s]
Range (min … max): 2.642 s … 2.742 s 20 runs
after:
Benchmark 1: nix search --no-eval-cache --offline ../nixpkgs hello
Time (mean ± σ): 6.902 s ± 0.039 s [User: 5.844 s, System: 0.783 s]
Range (min … max): 6.820 s … 6.956 s 20 runs
Benchmark 2: nix eval -f ../nixpkgs/pkgs/development/haskell-modules/hackage-packages.nix
Time (mean ± σ): 330.7 ms ± 2.2 ms [User: 300.6 ms, System: 30.0 ms]
Range (min … max): 327.5 ms … 334.5 ms 20 runs
Benchmark 3: nix eval --raw --impure --expr 'with import <nixpkgs/nixos> {}; system'
Time (mean ± σ): 2.330 s ± 0.027 s [User: 2.040 s, System: 0.234 s]
Range (min … max): 2.272 s … 2.383 s 20 runs
Nix
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
On Linux and macOS the easiest way to install Nix is to run the following shell command (as a user other than root):
$ curl -L https://nixos.org/nix/install | sh
Information on additional installation methods is available on the Nix download page.
Building And Developing
See our Hacking guide in our manual for instruction on how to build nix from source with nix-build or how to get a development environment.
Additional Resources
- Nix manual
- Nix jobsets on hydra.nixos.org
- NixOS Discourse
- Matrix - #nix:nixos.org
- IRC - #nixos on libera.chat
License
Nix is released under the LGPL v2.1.