|author||David 'Digit' Turner <firstname.lastname@example.org>||Thu Oct 15 23:40:55 2020 +0200|
|committer||Commit Bot <email@example.com>||Fri Nov 27 22:54:17 2020 +0000|
gn recipe: Link GN with rpmalloc to speed it up. NOTE: This is a reland of  with an updated rpmalloc revision that includes fixes for the -Wconversion errors that required reverting the original CL. This CL changes the GN recipe to link the executable with the rpmalloc allocator from https://github.com/mjansson/rpmalloc This speeds up the 'gn gen' operation of both Chromium and Fuchsia operations by 28% and 12% respectively , and has slightly better performance than using tcmalloc from gperftools in the Fuchsia case. Note that: - The sources are grabbed directly from github.com, but it might be desirable to use a Chromium or Fuchsia supported mirror instead. - Only Linux has been tested so far, so only this platform enables this build mode.  Median measurements from 10 runs of 'gn gen' using the default Linux allocator (glibc), gperftools' tcmalloc, and rpmalloc: Fuchsia: glibc (default): 9917 ms gperftools: 7858 ms (26% faster) rpmalloc: 7752 ms (28% faster) Chromium: glibc (default): 4742 ms gperftools: 4186 ms (13% faster) rpmalloc: 4235 ms (12% faster)  https://gn-review.googlesource.com/c/gn/+/9920 Change-Id: I0860c34437faee7c1f97e01f831cbf25f49c819e Reviewed-on: https://gn-review.googlesource.com/c/gn/+/10420 Commit-Queue: David Turner <firstname.lastname@example.org> Reviewed-by: Petr Hosek <email@example.com>
GN is a meta-build system that generates build files for Ninja.
Alternatively, you can build GN from source:
git clone https://gn.googlesource.com/gn cd gn python build/gen.py ninja -C out # To run tests: out/gn_unittests
On Windows, it is expected that
lib.exe can be found in
PATH, so you'll want to run from a Visual Studio command prompt, or similar.
On Linux and Mac, the default compiler is
clang++, a recent version is expected to be found in
PATH. This can be overridden by setting
There is a simple example in examples/simple_build directory that is a good place to get started with the minimal configuration.
To build and run the simple example with the default gcc compiler:
cd examples/simple_build ../../out/gn gen -C out ninja -C out ./out/hello
For a maximal configuration see the Chromium setup:
and the Fuchsia setup:
If you find a bug, you can see if it is known or report it in the bug database.
GN uses Gerrit for code review. The short version of how to patch is:
Register at https://gn-review.googlesource.com. ... edit code ... ninja -C out && out/gn_unittests
Then, to upload a change for review:
git commit git push origin HEAD:refs/for/master
The first time you do this you'll get an error from the server about a missing change-ID. Follow the directions in the error message to install the change-ID hook and run
git commit --amend to apply the hook to the current commit.
When revising a change, use:
git commit --amend git push origin HEAD:refs/for/master
which will add the new changes to the existing code review, rather than creating a new one.
We ask that all contributors sign Google's Contributor License Agreement (either individual or corporate as appropriate, select ‘any other Google project’).
You may ask questions and follow along with GN‘s development on Chromium’s gn-dev@ Google Group.