Eric Seidel
On Tue, Feb 16, 2016, at 05:49, Simon Peyton Jones wrote:
* We discussed it in our weekly GHC Skype chat yesterday. One thing that would really help is to make it laughably easy to track - Micro: whether my commit made anything significantly worse (compile time/allocs, run time/allocs, binary size) - Our current perf tests only complain when you go outside a window, but 90% of the lossage might have been from other patches, which demotivates dealing with it
It might be useful it phabricator ran the perf tests / nofib for every patch and displayed a warning (think a lint warning) if any of the metrics got worse. The warning would foster discussion about what caused the perf regression and whether it needs to be fixed *before* merging the patch.
Indeed we do already run the performance tests but at the moment you only get a thumbs-up or thumbs-down. One of my tasks for this week is to try adding better reporting of compiler performance in the testsuite driver. Cheers, - Ben