Re: slow execution of built executables on a Mac

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? Thanks! Richard

On Oct 30, 2018, at 2:32 PM, Gabor Greif wrote:

Maybe a symptom of an AFPS bug? https://gregoryszorc.com/blog/2018/10/29/global-kernel-locks-in-apfs/

Just came across this, might be worth a look.

Cheers,

Gabor

On 10/26/18, Richard Eisenberg wrote:

...

Hi devs,

I have a shiny, new iMac in my office. It's thus frustrating that it takes my iMac longer to build GHC than my trusty 28-month-old laptop. Building devel2 on a fresh checkout takes just about an hour. By contrast, my laptop is done after 30 minutes of work (same build settings). The laptop has a 2.8GHz Intel i7 running macOS 10.13.5; the desktop has a 3.5GHz Intel i5 running macOS 10.13.6. Both bootstrapped from the binary distro of GHC 8.6.1.

Watching GHC build, everything is snappy enough during the stage-1 build. But then, as soon as we start using GHC-produced executables, things slow down. It's most noticeable in the rts_dist_HC phase, which crawls. Stage 2 is pretty slow, too.

So: is there anything anyone knows about recent Macs not liking locally built executables? Or is there some local setting that I need to update? The prepackaged GHC seems to work well, so that gives me hope that someone knows what setting to tweak.

Thanks! Richard _______________________________________________ ghc-devs mailing list ghc-devs@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs