Richard Eisenberg
Sadly, none of the suggestions on this thread worked.
But here is some more detail:
- During stage-1, my machine's CPU is maxed out (or nearly so) in user mode. - After stage-1 (most obviously during rts_dist_HC), my machine spends roughly 80% of its CPU in *system* mode. - Testing on my other machine (which is slower, but much faster at building GHC), I never see high *system* percentages. - Both machines use APFS, which was one candidate for the slowdown. - The slow machine uses XCode 10.1; the fast one uses XCode 9.4.1 - The slow machine uses clang 10.0.0; the fast one uses clang 9.1.0 - `brew install gmp` on the slow machine tells me that gmp is already installed. - As a reminder: the slow machine is macOS 10.13.6; the fast one is macOS 10.13.5. I don't wish to try upgrading the fast one... lest that slow it down!
Does anyone have any insight?
Were you able to collect a few stacks from the slow processes? It sounds like the author of the original post was somehow able to do this. Under Linux I would just fire up perf and grab a system-wide profile. Knowing precisely what slow path you are hitting would help localize any possible problem in GHC. Cheers, - Ben