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?
