Re: [PATCH 03/19] sched/numa: Simplify load_too_imbalanced

Mel Gorman
2018-06-05T08:46:18Z

On Mon, Jun 04, 2018 at 03:30:12PM +0530, Srikar Dronamraju wrote:
> Currently load_too_imbalance() cares about the slope of imbalance.
> It doesn't care of the direction of the imbalance.
>
> However this may not work if nodes that are being compared have
> dissimilar capacities. Few nodes might have more cores than other nodes
> in the system. Also unlike traditional load balance at a NUMA sched
> domain, multiple requests to migrate from the same source node to same
> destination node may run in parallel. This can cause huge load
> imbalance. This is specially true on a larger machines with either large
> cores per node or more number of nodes in the system. Hence allow
> move/swap only if the imbalance is going to reduce.
>
> Testcase Time: Min Max Avg StdDev
> numa01.sh Real: 516.14 892.41 739.84 151.32
> numa01.sh Sys: 153.16 192.99 177.70 14.58
> numa01.sh User: 39821.04 69528.92 57193.87 10989.48
> numa02.sh Real: 60.91 62.35 61.58 0.63
> numa02.sh Sys: 16.47 26.16 21.20 3.85
> numa02.sh User: 5227.58 5309.61 5265.17 31.04
> numa03.sh Real: 739.07 917.73 795.75 64.45
> numa03.sh Sys: 94.46 136.08 109.48 14.58
> numa03.sh User: 57478.56 72014.09 61764.48 5343.69
> numa04.sh Real: 442.61 715.43 530.31 96.12
> numa04.sh Sys: 224.90 348.63 285.61 48.83
> numa04.sh User: 35836.84 47522.47 40235.41 3985.26
> numa05.sh Real: 386.13 489.17 434.94 43.59
> numa05.sh Sys: 144.29 438.56 278.80 105.78
> numa05.sh User: 33255.86 36890.82 34879.31 1641.98
>
> Testcase Time: Min Max Avg StdDev %Change
> numa01.sh Real: 435.78 653.81 534.58 83.20 38.39%
> numa01.sh Sys: 121.93 187.18 145.90 23.47 21.79%
> numa01.sh User: 37082.81 51402.80 43647.60 5409.75 31.03%
> numa02.sh Real: 60.64 61.63 61.19 0.40 0.637%
> numa02.sh Sys: 14.72 25.68 19.06 4.03 11.22%
> numa02.sh User: 5210.95 5266.69 5233.30 20.82 0.608%
> numa03.sh Real: 746.51 808.24 780.36 23.88 1.972%
> numa03.sh Sys: 97.26 108.48 105.07 4.28 4.197%
> numa03.sh User: 58956.30 61397.05 60162.95 1050.82 2.661%
> numa04.sh Real: 465.97 519.27 484.81 19.62 9.385%
> numa04.sh Sys: 304.43 359.08 334.68 20.64 -14.6%
> numa04.sh User: 37544.16 41186.15 39262.44 1314.91 2.478%
> numa05.sh Real: 411.57 457.20 433.29 16.58 0.380%
> numa05.sh Sys: 230.05 435.48 339.95 67.58 -17.9%
> numa05.sh User: 33325.54 36896.31 35637.84 1222.64 -2.12%
>
> Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>

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

--
Mel Gorman
SUSE Labs