Peter Zijlstra <pet...@infradead.org> writes: > On Wed, Jun 01, 2016 at 01:00:10PM +0800, Huang, Ying wrote: >> Hi, Peter, >> >> Peter Zijlstra <pet...@infradead.org> writes: >> >> > On Tue, May 31, 2016 at 04:34:36PM +0800, Huang, Ying wrote: >> >> Hi, Ingo, >> >> >> >> Part of the regression has been recovered in v4.7-rc1 from -32.9% to >> >> -9.8%. But there is still some regression. Is it possible for fully >> >> restore it? >> > >> > after much searching on how you guys run hackbench... I figured >> > something like: >> > >> > perf bench sched messaging -g 20 --thread -l 60000 >> >> There is a reproduce file attached in the original report email, its >> contents is something like below: >> >> 2016-05-15 08:57:02 echo performance > >> /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor > > <snip stupid large output> > >> 2016-05-15 09:06:24 /usr/bin/hackbench -g 24 --threads -l 60000 >> >> Hope that will help you for reproduce. > > It did not, because I didn't have the exact same machine and its not > apparent how I should modify -- if at all -- the arguments to be > representative when ran on my machine. > >> > on my IVB-EP (2*10*2) is similar to your IVT thing. >> > >> > And running something like: >> > >> > for i in /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor ; do echo >> > performance > $i ; done >> > perf stat --null --repeat 10 -- perf bench sched messaging -g 20 >> > --thread -l 60000 | grep "seconds time elapsed" >> > >> > gets me: >> > >> > v4.6: >> > >> > 36.786914089 seconds time elapsed ( +- 0.49% ) >> > 37.054017355 seconds time elapsed ( +- 1.05% ) >> > >> > >> > origin/master (v4.7-rc1-ish): >> > >> > 34.757435264 seconds time elapsed ( +- 3.34% ) >> > 35.396252515 seconds time elapsed ( +- 3.38% ) >> > >> > >> > Which doesn't show a regression between v4.6 and HEAD; in fact it shows >> > an improvement. >> >> Yes. For hackbench test, linus/master (v4.7-rc1+) is better than v4.6, >> but it is worse than v4.6-rc7. Details is as below. > > That kernel was broken.. what your point?
You mean the commit is a functionality fix? I found the hackbench.throughput for the test is v4.5: 1.4e+5 v4.6-rc1~v4.6-rc7: 1.9e+5 v4.6: 1.3e+5 v4.7-rc1: 1.7e+5 So some commit in v4.6-rc1 introduce some issue but improve the score for the test, which is fixed in v4.6, and some improvement merged by v4.7-rc1? Best Regards, Huang, Ying
