f8a8243bd3
Without this flag, the configure script prints a warning at the end, like this (reformatted): If you want a release build with all stable optimizations active (PGO, etc), please run ./configure --enable-optimizations We're doing a build to distribute to people for day-to-day use, doing things other than developing the Python interpreter. So that's certainly a release build -- we're the target audience for this recommendation. --- And, trying it out, upstream isn't kidding! I ran the standard benchmark suite that the CPython developers use for performance work, "pyperformance". Following its usage instructions: https://pyperformance.readthedocs.io/usage.html I ran the whole suite, like so: $ nix-shell -p ./result."$variant" --run ' cd $(mktemp -d); python -m venv venv; . venv/bin/activate pip install pyperformance pyperformance run -o ~/tmp/result.'"$variant"'.json ' and then examined the results with commands like: $ python -m pyperf compare_to --table -G \ ~/tmp/result.{$before,$after}.json Across all the benchmarks in the suite, the median speedup was 16%. (Meaning 1.16x faster; 14% less time). The middle half of them ranged from a 13% to a 22% speedup. Each of the 60 benchmarks in the suite got faster, by speedups ranging from 3% to 53%. --- One reason this isn't just the default to begin with is that, until recently, it made the build a lot slower. What it does is turn on profile-guided optimization, which means first build for profiling, then run some task to get a profile, then build again using the profile. And, short of further customization, the task it would use would be nearly the full test suite, which includes a lot of expensive and slow tests, and can easily take half an hour to run. Happily, in 2019 an upstream developer did the work to carefully select a more appropriate set of tests to use for the profile: https://github.com/python/cpython/commit/4e16a4a31 https://bugs.python.org/issue36044 This suite takes just 2 minutes to run. And the resulting final build is actually slightly faster than with the much longer suite, at least as measured by those standard "pyperformance" benchmarks. That work went into the 3.8 release, but the same list works great if used on older releases too. So, start passing that --enable-optimizations flag; and backport that good-for-PGO set of tests, so that we use it on all releases. |
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| README.md | ||
Nixpkgs is a collection of over 40,000 software packages that can be installed with the Nix package manager. It also implements NixOS, a purely-functional Linux distribution.
Manuals
- NixOS Manual - how to install, configure, and maintain a purely-functional Linux distribution
- Nixpkgs Manual - contributing to Nixpkgs and using programming-language-specific Nix expressions
- Nix Package Manager Manual - how to write Nix expressions (programs), and how to use Nix command line tools
Community
- Discourse Forum
- IRC - #nixos on freenode.net
- NixOS Weekly
- Community-maintained wiki
- Community-maintained list of ways to get in touch (Discord, Matrix, Telegram, other IRC channels, etc.)
Other Project Repositories
The sources of all official Nix-related projects are in the NixOS organization on GitHub. Here are some of the main ones:
- Nix - the purely functional package manager
- NixOps - the tool to remotely deploy NixOS machines
- Nix RFCs - the formal process for making substantial changes to the community
- NixOS homepage - the NixOS.org website
- hydra - our continuous integration system
- NixOS Artwork - NixOS artwork
Continuous Integration and Distribution
Nixpkgs and NixOS are built and tested by our continuous integration system, Hydra.
- Continuous package builds for unstable/master
- Continuous package builds for the NixOS 19.09 release
- Tests for unstable/master
- Tests for the NixOS 19.09 release
Artifacts successfully built with Hydra are published to cache at https://cache.nixos.org/. When successful build and test criteria are met, the Nixpkgs expressions are distributed via Nix channels.
Contributing
Nixpkgs is among the most active projects on GitHub. While thousands of open issues and pull requests might seem a lot at first, it helps consider it in the context of the scope of the project. Nixpkgs describes how to build over 40,000 pieces of software and implements a Linux distribution. The GitHub Insights page gives a sense of the project activity.
Community contributions are always welcome through GitHub Issues and Pull Requests. When pull requests are made, our tooling automation bot, OfBorg will perform various checks to help ensure expression quality.
The Nixpkgs maintainers are people who have assigned themselves to maintain specific individual packages. We encourage people who care about a package to assign themselves as a maintainer. When a pull request is made against a package, OfBorg will notify the appropriate maintainer(s). The Nixpkgs committers are people who have been given permission to merge.
Most contributions are based on and merged into these branches:
masteris the main branch where all small contributions gostagingis branched from master, changes that have a big impact on Hydra builds go to this branchstaging-nextis branched from staging and only fixes to stabilize and security fixes with a big impact on Hydra builds should be contributed to this branch. This branch is merged into master when deemed of sufficiently high quality
For more information about contributing to the project, please visit the contributing page.
Donations
The infrastructure for NixOS and related projects is maintained by a nonprofit organization, the NixOS Foundation. To ensure the continuity and expansion of the NixOS infrastructure, we are looking for donations to our organization.
You can donate to the NixOS foundation by using Open Collective:
License
Nixpkgs is licensed under the MIT License.
Note: MIT license does not apply to the packages built by Nixpkgs, merely to the files in this repository (the Nix expressions, build scripts, NixOS modules, etc.). It also might not apply to patches included in Nixpkgs, which may be derivative works of the packages to which they apply. The aforementioned artifacts are all covered by the licenses of the respective packages.