On 26.08.2014 21:54, Slawa Olhovchenkov wrote: > On Tue, May 20, 2014 at 09:04:25AM -0700, Adrian Chadd wrote: > >> On 20 May 2014 08:41, Slawa Olhovchenkov <s...@zxy.spb.ru> wrote: >> >>>> (But if you try it on 10.0 and it changes things, by all means let me >>>> know.) >>> >>> I am try on 10.0, but not sure about significant improvement (may be >>> 10%). >>> >>> For current CPU (E5-2650 v2 @ 2.60GHz) hwpmc don't working (1. after >>> collect some data `pmcstat -R sample.out -G out.txt` don't decode any; >>> 2. kldunload hwpmc do kernel crash) and I can't collect detailed >>> profile information. >> >> Yup. I'm starting to get really ticked off at how pmc logging on >> multi-core devices just "stops" after a while. I'll talk with other >> pmc people and see if we can figure out what the heck is going on. :( > > Now I can test you work on CPU w/ working pmc. > @ CPU_CLK_UNHALTED_CORE [241440 samples] > > 10.59% [25561] _mtx_lock_spin_cookie @ /boot/kernel/kernel > 94.25% [24092] pmclog_reserve @ /boot/kernel/hwpmc.ko > 100.0% [24092] pmclog_process_callchain > 100.0% [24092] pmc_process_samples > 100.0% [24092] pmc_hook_handler > 100.0% [24092] hardclock_cnt @ /boot/kernel/kernel
Slava, on large SMP systems you should specify some much bigger division rate (like `-n 100000000`) when doing PMC sampling. Otherwise you are mostly measuring PMC's internal lock congestion. -- Alexander Motin _______________________________________________ svn-src-all@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"
