On Thu, Feb 21, 2019 at 11:46:12AM +0800, Wei Yang wrote: > On Thu, Feb 21, 2019 at 11:10:49AM +0800, kernel test robot wrote: > >On Tue, Feb 19, 2019 at 01:19:04PM +0100, Greg Kroah-Hartman wrote: > >> On Tue, Feb 19, 2019 at 08:59:45AM +0800, Wei Yang wrote: > >> > On Mon, Feb 18, 2019 at 03:54:42PM +0800, kernel test robot wrote: > >> > >Greeting, > >> > > > >> > >FYI, we noticed a -12.2% regression of will-it-scale.per_thread_ops due > >> > >to commit: > >> > > > >> > > > >> > >commit: 570d0200123fb4f809aa2f6226e93a458d664d70 ("driver core: move > >> > >device->knode_class to device_private") > >> > >https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git master > >> > > > >> > > >> > This is interesting. > >> > > >> > I didn't expect the move of this field will impact the performance. > >> > > >> > The reason is struct device is a hotter memory than > >> > device->device_private? > >> > > >> > >in testcase: will-it-scale > >> > >on test machine: 288 threads Knights Mill with 80G memory > >> > >with following parameters: > >> > > > >> > > nr_task: 100% > >> > > mode: thread > >> > > test: unlink2 > >> > > cpufreq_governor: performance > >> > > > >> > >test-description: Will It Scale takes a testcase and runs it from 1 > >> > >through to n parallel copies to see if the testcase will scale. It > >> > >builds both a process and threads based test in order to see any > >> > >differences between the two. > >> > >test-url: https://github.com/antonblanchard/will-it-scale > >> > > > >> > >In addition to that, the commit also has significant impact on the > >> > >following tests: > >> > > > >> > >+------------------+---------------------------------------------------------------+ > >> > >| testcase: change | will-it-scale: will-it-scale.per_thread_ops -29.9% > >> > >regression | > >> > >| test machine | 288 threads Knights Mill with 80G memory > >> > > | > >> > >| test parameters | cpufreq_governor=performance > >> > > | > >> > >| | mode=thread > >> > > | > >> > >| | nr_task=100% > >> > > | > >> > >| | test=signal1 > >> > > | > >> > >> Ok, I'm going to blame your testing system, or something here, and not > >> the above patch. > >> > >> All this test does is call raise(3). That does not touch the driver > >> core at all. > >> > >> > >+------------------+---------------------------------------------------------------+ > >> > >| testcase: change | will-it-scale: will-it-scale.per_thread_ops -16.5% > >> > >regression | > >> > >| test machine | 288 threads Knights Mill with 80G memory > >> > > | > >> > >| test parameters | cpufreq_governor=performance > >> > > | > >> > >| | mode=thread > >> > > | > >> > >| | nr_task=100% > >> > > | > >> > >| | test=open1 > >> > > | > >> > >+------------------+---------------------------------------------------------------+ > >> > >> Same here, open1 just calls open/close a lot. No driver core > >> interaction at all there either. > >> > >> So are you _sure_ this is the offending patch? > > > >Hi Greg, > > > >We did an experiment, recovered the layout of struct device. and we > >found the regression is gone. I guess the regession is not from the > >patch but related to the struct layout. > > > > > >tests: 1 > >testcase/path_params/tbox_group/run: > >will-it-scale/performance-thread-100%-unlink2/lkp-knm01 > > > >570d0200123fb4f8 a36dc70b810afe9183de2ea18f > >---------------- -------------------------- > > %stddev change %stddev > > \ | \ > > 237096 14% 270789 will-it-scale.workload > > 823 14% 939 will-it-scale.per_thread_ops > > > > Do you have the comparison between a36dc70b810afe9183de2ea18f and the one > before 570d020012?
testcase/path_params/tbox_group/run: will-it-scale/performance-thread-100%-unlink2/lkp-knm01 4bd4e92cfe6d2af7 a36dc70b810afe9183de2ea18f ---------------- -------------------------- %stddev %change %stddev \ | \ 937.00 +0.2% 939.33 will-it-scale.per_thread_ops 269989 +0.3% 270789 will-it-scale.workload > > > >tests: 1 > >testcase/path_params/tbox_group/run: > >will-it-scale/performance-thread-100%-signal1/lkp-knm01 > > > >570d0200123fb4f8 a36dc70b810afe9183de2ea18f > >---------------- -------------------------- > > %stddev change %stddev > > \ | \ > > 93.51 ± 3% 48% 138.53 ± 3% will-it-scale.time.user_time > > 186 40% 261 will-it-scale.per_thread_ops > > 53909 40% 75507 will-it-scale.workload > > testcase/path_params/tbox_group/run: will-it-scale/performance-thread-100%-signal1/lkp-knm01 4bd4e92cfe6d2af7 a36dc70b810afe9183de2ea18f ---------------- -------------------------- %stddev %change %stddev \ | \ 266.00 ± 2% -1.6% 261.67 will-it-scale.per_thread_ops 76699 ± 2% -1.6% 75507 will-it-scale.workload > > > >tests: 1 > >testcase/path_params/tbox_group/run: > >will-it-scale/performance-thread-100%-open1/lkp-knm01 > > > >570d0200123fb4f8 a36dc70b810afe9183de2ea18f > >---------------- -------------------------- > > %stddev change %stddev > > \ | \ > > 447722 22% 546258 ± 10% > > will-it-scale.time.involuntary_context_switches > > 226995 19% 269751 will-it-scale.workload > > 787 19% 936 will-it-scale.per_thread_ops > > > > testcase/path_params/tbox_group/run: will-it-scale/performance-thread-100%-open1/lkp-knm01 4bd4e92cfe6d2af7 a36dc70b810afe9183de2ea18f ---------------- -------------------------- %stddev %change %stddev \ | \ 944.60 -0.9% 936.00 will-it-scale.per_thread_ops 272252 -0.9% 269751 will-it-scale.workload Best Regards, Rong Chen