Messages in this thread | | | Date | Wed, 9 May 2018 10:32:12 +0800 | From | Aaron Lu <> | Subject | Re: [LKP] [lkp-robot] [mm] e27be240df: will-it-scale.per_process_ops -27.2% regression |
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On Tue, May 08, 2018 at 01:26:40PM -0400, Johannes Weiner wrote: > Hello, > > On Tue, May 08, 2018 at 01:34:51PM +0800, kernel test robot wrote: > > FYI, we noticed a -27.2% regression of will-it-scale.per_process_ops due to commit: > > > > > > commit: e27be240df53f1a20c659168e722b5d9f16cc7f4 ("mm: memcg: make sure memory.events is uptodate when waking pollers") > > https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git master > > > > in testcase: will-it-scale > > on test machine: 72 threads Intel(R) Xeon(R) CPU E5-2699 v3 @ 2.30GHz with 128G memory > > with following parameters: > > > > nr_task: 100% > > mode: process > > test: page_fault3 > > 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 > > This is surprising. Do you run these tests in a memory cgroup with a > limit set? Can you dump that cgroup's memory.events after the run?
There is no cgroup related setup so yes, this is surprising. But the result is quite stable, I have just confirmed on another Haswell-EP machine.
perf shows increased cycles spent for lock_page_memcg and unlock_page_memcg, maybe this can shed some light. Full profile for this commit and its parent are attached.
I have also attached dmesg for both commits in case they are useful, please feel free to let me know if you need any other information. We also collected a ton of other information during the run like /proc/vmstat, /proc/meminfo, /proc/interrupt etc. [unhandled content-type:application/gzip][unhandled content-type:application/gzip][unhandled content-type:application/x-xz][unhandled content-type:application/x-xz] | |