Messages in this thread | | | From | Linus Torvalds <> | Date | Mon, 5 Nov 2018 09:50:09 -0800 | Subject | Re: [LKP] [mm] 9bc8039e71: will-it-scale.per_thread_ops -64.1% regression |
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On Sun, Nov 4, 2018 at 9:08 PM kernel test robot <rong.a.chen@intel.com> wrote: > > FYI, we noticed a -64.1% regression of will-it-scale.per_thread_ops > due to commit 9bc8039e715d ("mm: brk: downgrade mmap_sem to read when > shrinking")
Ugh. That looks pretty bad.
> in testcase: will-it-scale > on test machine: 8 threads Ivy Bridge with 16G memory > with following parameters: > > nr_task: 100% > mode: thread > test: brk1 > ucode: 0x20 > cpufreq_governor: performance
The reason seems to be way more scheduler time due to lots more context switches:
> 34925294 ± 18% +270.3% 1.293e+08 ± 4% will-it-scale.time.voluntary_context_switches
Yang Shi, would you mind taking a look at what's going on?
Linus
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