Tom Ellis
A user posted the following to the ghc-proposals repository. Both JB and RAE suggested ghc-devs as a more appropriate forum. Since I have no idea whether the user has even ever used a mailing list before I thought I would lower the activation energy by posting their message for them.
https://github.com/ghc-proposals/ghc-proposals/issues/410
Hi,
Does the GHC release or development process include regression testing for performance?
Is this the place to discuss ideas for implementing such a thing and to eventually craft a proposal?
I believe the performance impact of changes to GHC needs to be verified/validated before release. I also believe this would be feasible if we tracked metrics on building a wide variety of real-world packages. Using real-world packages is one of the best ways to see the actual impact users will experience. It's also a great way to broaden the scope of tests, particularly with the combination of language pragmas and enabled features within the compiler.
We already do this, but help is definitely wanted! In short, every commit to GHC goes through a variety of performance testing including: * the performance testsuite in `base` (which I'm sure all GHC developers are all-too-familiar with at this point) * a run of the nofib benchmark suite * compile-time benchmarking using the head.hackage patchset (when it is buildable) In addition to being preserved as CI artifacts, all of this information also gets thrown into a PostgreSQL database (see [1]) which is exposed via Postgrest. The problem is that we currently don't *do* anything with it. I have occassionally found it useful to do quick queries against it, but it would be great if someone would step up to help improve this infrastructure. Cheers, - Ben [1] https://github.com/bgamari/ghc-perf-import