Thanks Moritz for that update. The latest is that currently darwin CI is disabled and the merge train is unblocked (*choo choo*).
I am testing Moritz's patches to speed-up CI and will merge them in shortly to get darwin coverage back. Cheers, Matt On Wed, May 19, 2021 at 9:46 AM Moritz Angermann <moritz.angerm...@gmail.com> wrote: > > Matt has access to the M1 builder in my closet now. The darwin performance > issue > is mainly there since BigSur, and (afaik) primarily due to the amount of > DYLD_LIBRARY_PATH's > we pass to GHC invocations. The system linker spends the majority of the time > in the > kernel stat'ing and getelements (or some similar directory) call for each and > every possible > path. > > Switching to hadrian will cut down the time from ~5hs to ~2hs. At some point > we had make > builds <90min by just killing all DYLD_LIBRARY_PATH logic we ever had, but > that broke > bindists. > > The CI has time values attached and some summary at the end right now, which > highlights > time spent in the system and in user mode. This is up to 80% sys, 20% user, > and went to > something like 20% sys, 80% user after nuking all DYLD_LIBRARY_PATH's, with > hadrian it's > closer to ~25% sys, 75% user. > > Of note, this is mostly due to time spent during the *test-suite*, not the > actual build. For the > actual build make and hadrian are comparable, though I've seen hadrian to > oddly have a > much higher variance in how long it takes to *build* ghc, whereas the make > build was more > consistent. > > The test-suite quite notoriously calls GHC *a lot of times*, which makes any > linker issue due > to DYLD_LIBRARY_PATH (and similar lookups) much worse. > > If we would finally split building and testing, we'd see this more clearly I > believe. Maybe this > is motivation enough for someone to come forward to break build/test into two > CI steps? > > Cheers, > Moritz > > On Wed, May 19, 2021 at 4:14 PM Matthew Pickering > <matthewtpicker...@gmail.com> wrote: >> >> Hi all, >> >> The darwin pipelines are gumming up the merge pipeline as they are >> taking over 4 hours to complete on average. >> >> I am going to disable them - >> https://gitlab.haskell.org/ghc/ghc/-/merge_requests/5785 >> >> Please can someone give me access to one of the M1 builders so I can >> debug why the tests are taking so long. Once I have fixed the issue >> then I will enable the pipelines. >> >> Cheers, >> >> Matt _______________________________________________ ghc-devs mailing list ghc-devs@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs
