lkml.org 
[lkml]   [2018]   [Jun]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v2 13/19] mm/migrate: Use xchg instead of spinlock
On Wed, Jun 20, 2018 at 10:32:54PM +0530, Srikar Dronamraju wrote:
> Currently resetting the migrate rate limit is under a spinlock.
> The spinlock will only serialize the migrate rate limiting and something
> similar can actually be achieved by a simpler xchg.
>
> Running SPECjbb2005 on a 4 node machine and comparing bops/JVM
> JVMS LAST_PATCH WITH_PATCH %CHANGE
> 16 25804.1 25355.9 -1.73
> 1 73413 72812 -0.81
>
> Running SPECjbb2005 on a 16 node machine and comparing bops/JVM
> JVMS LAST_PATCH WITH_PATCH %CHANGE
> 8 101748 110199 8.30
> 1 170818 176303 3.21
>
> (numbers from v1 based on v4.17-rc5)
> Testcase Time: Min Max Avg StdDev
> numa01.sh Real: 435.67 707.28 527.49 97.85
> numa01.sh Sys: 76.41 231.19 162.49 56.13
> numa01.sh User: 38247.36 59033.52 45129.31 7642.69
> numa02.sh Real: 60.35 62.09 61.09 0.69
> numa02.sh Sys: 15.01 30.20 20.64 5.56
> numa02.sh User: 5195.93 5294.82 5240.99 40.55
> numa03.sh Real: 752.04 919.89 836.81 63.29
> numa03.sh Sys: 115.10 133.35 125.46 7.78
> numa03.sh User: 58736.44 70084.26 65103.67 4416.10
> numa04.sh Real: 418.43 709.69 512.53 104.17
> numa04.sh Sys: 242.99 370.47 297.39 42.20
> numa04.sh User: 34916.14 48429.54 38955.65 4928.05
> numa05.sh Real: 379.27 434.05 403.70 17.79
> numa05.sh Sys: 145.94 344.50 268.72 68.53
> numa05.sh User: 32679.32 35449.75 33989.10 913.19
>
> Testcase Time: Min Max Avg StdDev %Change
> numa01.sh Real: 490.04 774.86 596.26 96.46 -11.5%
> numa01.sh Sys: 151.52 242.88 184.82 31.71 -12.0%
> numa01.sh User: 41418.41 60844.59 48776.09 6564.27 -7.47%
> numa02.sh Real: 60.14 62.94 60.98 1.00 0.180%
> numa02.sh Sys: 16.11 30.77 21.20 5.28 -2.64%
> numa02.sh User: 5184.33 5311.09 5228.50 44.24 0.238%
> numa03.sh Real: 790.95 856.35 826.41 24.11 1.258%
> numa03.sh Sys: 114.93 118.85 117.05 1.63 7.184%
> numa03.sh User: 60990.99 64959.28 63470.43 1415.44 2.573%
> numa04.sh Real: 434.37 597.92 504.87 59.70 1.517%
> numa04.sh Sys: 237.63 397.40 289.74 55.98 2.640%
> numa04.sh User: 34854.87 41121.83 38572.52 2615.84 0.993%
> numa05.sh Real: 386.77 448.90 417.22 22.79 -3.24%
> numa05.sh Sys: 149.23 379.95 303.04 79.55 -11.3%
> numa05.sh User: 32951.76 35959.58 34562.18 1034.05 -1.65%
>
> Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>

Acked-by: Mel Gorman <mgorman@techsingularity.net>

However, I'm actively considering removing rate limiting entirely. It
has been reported elsewhere that it was a limiting factor for some
workloads. When it was introduced, it was to avoid worst-case migration
storms but I believe that those ping-pong style problems should now be
ok.

--
Mel Gorman
SUSE Labs

\
 
 \ /
  Last update: 2018-06-21 11:51    [W:0.216 / U:1.152 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site