Re: [lkp-robot] [fs] 3deb642f0d: will-it-scale.per_process_ops -8.8% regression

Christoph Hellwig
2018-06-28T13:38:38Z

On Thu, Jun 28, 2018 at 08:38:34AM +0800, Ye Xiaolong wrote:
> Update the result:
>
> testcase/path_params/tbox_group/run: will-it-scale/poll2-performance/lkp-sb03

So this looks like a huge improvement in the per process ops, but not
as large as the original regression, and no change in the per-thread
ops.

But the baseline already looks much lower, e.g. this shows an improvement
from 404611 to 424608 for the per-process ops, while the original showed
a regression from 501456 to 457120. Are we measuring on different
hardware? Did we gain new spectre mitigations elsewhere? Either way
I'm going to send these patches out for review, but I'd like to understand
the numbers a bit more.

>
> 894b8c000ae6c106 8fbedc19c94fd25a2b9b327015
> ---------------- --------------------------
> %stddev change %stddev
> \ | \
> 404611 ± 4% 5% 424608 will-it-scale.per_process_ops
> 1489 ± 21% 28% 1899 ± 18% will-it-scale.time.voluntary_context_switches
> 45828560 46155690 will-it-scale.workload
> 2337 2342 will-it-scale.time.system_time
> 806 806 will-it-scale.time.percent_of_cpu_this_job_got
> 310 310 will-it-scale.time.elapsed_time
> 310 310 will-it-scale.time.elapsed_time.max
> 4096 4096 will-it-scale.time.page_size
> 233917 233862 will-it-scale.per_thread_ops
> 17196 17179 will-it-scale.time.minor_page_faults
> 9901 9862 will-it-scale.time.maximum_resident_set_size
> 14705 ± 3% 14397 ± 4% will-it-scale.time.involuntary_context_switches
> 167 163 will-it-scale.time.user_time
> 0.66 ± 25% -17% 0.54 will-it-scale.scalability
> 120508 ± 15% -7% 112098 ± 5% interrupts.CAL:Function_call_interrupts
> 1670 ± 3% 10% 1845 ± 3% vmstat.system.cs
> 32707 32635 vmstat.system.in
> 121 122 turbostat.CorWatt
> 149 150 turbostat.PkgWatt
> 1573 1573 turbostat.Avg_MHz
> 17.54 ± 19% 17.77 ± 19% boot-time.kernel_boot
> 824 ± 12% 834 ± 12% boot-time.idle
> 27.45 ± 12% 27.69 ± 12% boot-time.boot
> 16.96 ± 21% 16.93 ± 21% boot-time.dhcp
> 1489 ± 21% 28% 1899 ± 18% time.voluntary_context_switches
> 2337 2342 time.system_time
> 806 806 time.percent_of_cpu_this_job_got
> 310 310 time.elapsed_time
> 310 310 time.elapsed_time.max
> 4096 4096 time.page_size
> 17196 17179 time.minor_page_faults
> 9901 9862 time.maximum_resident_set_size
> 14705 ± 3% 14397 ± 4% time.involuntary_context_switches
> 167 163 time.user_time
> 18320 6% 19506 ± 8% proc-vmstat.nr_slab_unreclaimable
> 1518 ± 7% 1558 ± 10% proc-vmstat.numa_hint_faults
> 1387 ± 8% 1421 ± 9% proc-vmstat.numa_hint_faults_local
> 1873 ± 5% 1917 ± 8% proc-vmstat.numa_pte_updates
> 19987 20005 proc-vmstat.nr_anon_pages
> 8464 8471 proc-vmstat.nr_kernel_stack
> 309815 310062 proc-vmstat.nr_file_pages
> 50828 50828 proc-vmstat.nr_free_cma
> 16065590 16064831 proc-vmstat.nr_free_pages
> 3194669 3194517 proc-vmstat.nr_dirty_threshold
> 1595384 1595308 proc-vmstat.nr_dirty_background_threshold
> 798886 797937 proc-vmstat.pgfault
> 6510 6499 proc-vmstat.nr_mapped
> 659089 657491 proc-vmstat.numa_local
> 665458 663786 proc-vmstat.numa_hit
> 1037 1033 proc-vmstat.nr_page_table_pages
> 669923 665906 proc-vmstat.pgfree
> 676982 672385 proc-vmstat.pgalloc_normal
> 6368 6294 proc-vmstat.numa_other
> 13013 -7% 12152 ± 11% proc-vmstat.nr_slab_reclaimable
> 51213164 ± 18% 23% 63014695 ± 25% perf-stat.node-loads
> 22096136 ± 28% 20% 26619357 ± 35% perf-stat.node-load-misses
> 2.079e+08 ± 9% 12% 2.323e+08 ± 11% perf-stat.cache-misses
> 515039 ± 3% 10% 568299 ± 3% perf-stat.context-switches
> 3.283e+08 ± 22% 10% 3.622e+08 ± 5% perf-stat.iTLB-loads
>
> Thanks,
> Xiaolong
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