pennae
5838354d34
constructing an ostringstream for non-string concats (like integer addition) is
a small constant cost that we can avoid. for string concats we can keep all the
string temporaries we get from coerceToString and concatenate them in one go,
which saves a lot of intermediate temporaries and copies in ostringstream. we
can also avoid copying the concatenated string again by directly allocating it
in GC memory and moving ownership of the concatenated string into the target
value.
saves about 2% on system eval.
before:
Benchmark 1: nix eval --raw --impure --expr 'with import <nixpkgs/nixos> {}; system'
Time (mean ± σ): 2.837 s ± 0.031 s [User: 2.562 s, System: 0.191 s]
Range (min … max): 2.796 s … 2.892 s 20 runs
after:
Benchmark 1: nix eval --raw --impure --expr 'with import <nixpkgs/nixos> {}; system'
Time (mean ± σ): 2.790 s ± 0.035 s [User: 2.532 s, System: 0.187 s]
Range (min … max): 2.722 s … 2.836 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.