Re: [RFC][PATCH 0/5] select_idle_sibling() wreckage

[Vincent Guittot]

On Wed, 16 Dec 2020 at 14:00, Li, Aubrey <aubrey.li@xxxxxxxxxxxxxxx> wrote:
>
> Hi Peter,
>
> On 2020/12/15 0:48, Peter Zijlstra wrote:
> > Hai, here them patches Mel asked for. They've not (yet) been through the
> > robots, so there might be some build fail for configs I've not used.
> >
> > Benchmark time :-)
> >
>
> Here is the data on my side, benchmarks were tested on a x86 4 sockets system
> with 24 cores per socket and 2 hyperthreads per core, total 192 CPUs.
>
> uperf throughput: netperf workload, tcp_nodelay, r/w size = 90
>
>   threads       baseline-avg    %std    patch-avg       %std
>   96            1               0.78    1.0072          1.09
>   144           1               0.58    1.0204          0.83
>   192           1               0.66    1.0151          0.52
>   240           1               2.08    0.8990          0.75
>
> hackbench: process mode, 25600 loops, 40 file descriptors per group
>
>   group         baseline-avg    %std    patch-avg       %std
>   2(80)         1               10.02   1.0339          9.94
>   3(120)        1               6.69    1.0049          6.92
>   4(160)        1               6.76    0.8663          8.74
>   5(200)        1               2.96    0.9651          4.28
>
> schbench: 99th percentile latency, 16 workers per message thread
>
>   mthread       baseline-avg    %std    patch-avg       %std
>   6(96)         1               0.88    1.0055          0.81
>   9(144)        1               0.59    1.0007          0.37
>   12(192)       1               0.61    0.9973          0.82
>   15(240)       1               25.05   0.9251          18.36
>
> sysbench mysql throughput: read/write, table size = 10,000,000
>
>   thread        baseline-avg    %std    patch-avg       %std
>   96            1               6.62    0.9668          4.04
>   144           1               9.29    0.9579          6.53
>   192           1               9.52    0.9503          5.35
>   240           1               8.55    0.9657          3.34
>
> It looks like
> - hackbench has a significant improvement of 4 groups
> - uperf has a significant regression of 240 threads

Tests are still running on my side but early results shows perf
regression for hackbench

>
> Please let me know if you have any interested cases I can run/rerun.
>
> Thanks,
> -Aubrey