Re: [LKP] [sched/numa] a43455a1d57: +94.1% proc-vmstat.numa_hint_faults_local

From: Jirka Hladky
Date: Fri Aug 01 2014 - 17:31:11 EST


On 08/01/2014 10:46 PM, Davidlohr Bueso wrote:
On Thu, 2014-07-31 at 18:16 +0200, Jirka Hladky wrote:
Peter, I'm seeing regressions for

SINGLE SPECjbb instance for number of warehouses being the same as total
number of cores in the box.

Example: 4 NUMA node box, each CPU has 6 cores => biggest regression is
for 24 warehouses.
By looking at your graph, that's around a 10% difference.

So I'm not seeing anywhere near as bad a regression on a 80-core box.
Testing single with 80 warehouses, I get:

tip/master baseline:
677476.36 bops
705826.70 bops
704870.87 bops
681741.20 bops
707014.59 bops

Avg: 695385.94 bops

tip/master + patch (NUMA_SCALE/8 variant):
698242.66 bops
693873.18 bops
707852.28 bops
691785.96 bops
747206.03 bopsthis

Avg: 707792.022 bops

So both these are pretty similar, however, when reverting, on avg we
increase the amount of bops a mere ~4%:

tip/master + reverted:
778416.02 bops
702602.62 bops
712557.32 bops
713982.90 bops
783300.36 bops

Avg: 738171.84 bops

Are there perhaps any special specjbb options you are using?


I see the regression only on this box. It has 4 "Ivy Bridge-EX" Xeon E7-4890 v2 CPUs.

http://ark.intel.com/products/75251
http://en.wikipedia.org/wiki/List_of_Intel_Xeon_microprocessors#.22Ivy_Bridge-EX.22_.2822_nm.29_Expandable_2

Please rerun the test on box with Ivy Bridge CPUs. It seems that older CPU generations are not affected.

Thanks
Jirka


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