0395b9b94a
'builtins.memoise f x' is equal to 'f x', but uses a cache to speed up
repeated invocations of 'f' with the same 'x'. A typical application
is memoising evaluations of Nixpkgs in NixOps network
specifications. For example, with the patch below, the time to
evaluate a 10-machine NixOps network is reduced from 17.1s to 9.6s,
while memory consumption goes from 4486 MiB to 3089 MiB. (This is with
GC_INITIAL_HEAP_SIZE=16G.)
Nixpkgs patch:
diff --git a/pkgs/top-level/impure.nix b/pkgs/top-level/impure.nix
index a9f21e45aed..f641067e022 100644
--- a/pkgs/top-level/impure.nix
+++ b/pkgs/top-level/impure.nix
@@ -79,7 +79,7 @@ in
# not be passed.
assert args ? localSystem -> !(args ? system || args ? platform);
-import ./. (builtins.removeAttrs args [ "system" "platform" ] // {
+builtins.memoise or (x: x) (import ./.) (builtins.removeAttrs args [ "system" "platform" ] // {
inherit config overlays crossSystem;
# Fallback: Assume we are building packages on the current (build, in GNU
# Autotools parlance) system.
|
||
|---|---|---|
| .github | ||
| config | ||
| corepkgs | ||
| doc/manual | ||
| maintainers | ||
| misc | ||
| mk | ||
| perl | ||
| scripts | ||
| src | ||
| tests | ||
| .dir-locals.el | ||
| .editorconfig | ||
| .gitignore | ||
| .travis.yml | ||
| COPYING | ||
| Makefile | ||
| Makefile.config.in | ||
| README.md | ||
| bootstrap.sh | ||
| configure.ac | ||
| local.mk | ||
| nix.spec.in | ||
| release-common.nix | ||
| release.nix | ||
| shell.nix | ||
| version | ||
README.md
Nix, the purely functional package manager
Nix is a new take on package management that is fairly unique. Because of its purity aspects, a lot of issues found in traditional package managers don't appear with Nix.
To find out more about the tool, usage and installation instructions, please read the manual, which is available on the Nix website at http://nixos.org/nix/manual.
Contributing
Take a look at the Hacking Section of the manual. It helps you to get started with building Nix from source.
License
Nix is released under the LGPL v2.1
This product includes software developed by the OpenSSL Project for use in the OpenSSL Toolkit.