Re: [PATCH v2] sched: wake-affine throttle

[Michael Wang <wangyun@linux.vnet.ibm.com>]

On 05/22/2013 10:55 PM, Mike Galbraith wrote:
> On Wed, 2013-05-22 at 17:25 +0800, Michael Wang wrote:
> 
>> I've not test the hackbench with wakeup-buddy before, will do it this
>> time, I suppose the 15% illegal income will suffered, anyway, it's
>> illegal :)
> 
> On a 4 socket 40 core (+SMT) box, hackbench wasn't too happy.

I've done more test and now I got the reason of regression...

The writer and reader in hackbench is N:N, prev writer will write all
the fd then switch to next writer and repeat the same work, so it's
impossible to setup the buddy relationship by just record the last one,
and we have to record all the waker/wakee in history, but that means
unacceptable memory overhead...

So this buddy idea seems to be bad...

I think a better way may should be allowing pull in most time, but
filter the very bad cases carefully.

For workload like pgbench, we actually just need to avoid pull if that
will damage the 'mother' thread, which is busy and be relied by many
'child'.

I will send out a new implementation, let's see whether it could solve
the problems ;-)

Regards,
Michael Wang

> 
> defaultx = wakeup buddy
> 
> tbench 30 localhost
>                          1       5       10       20       40       80      160      320
> 3.10.0-default      188.13  953.03  1860.03  3180.93  5378.34 10826.06 11342.90 11651.30
> 3.10.0-defaultx     187.26  934.55  1859.30  3160.29  5016.35 12477.15 12567.05 12068.47
> 
> hackbench -l 400 -g 400
> 3.10.0-default     Time: 3.919    4.250     4.116
> 3.10.0-defaultx    Time: 9.074   10.985     9.849
> 
> aim7 compute
> AIM Multiuser Benchmark - Suite VII     "1.1"   3.10.0-default     AIM Multiuser Benchmark - Suite VII     "1.1"   3.10.0-defaultx
> 
> Tasks   Jobs/Min        JTI     Real    CPU     Jobs/sec/task      Tasks   Jobs/Min        JTI     Real    CPU     Jobs/sec/task
> 1       428.0           100     14.2    4.1     7.1328             1       428.9           100     14.1    4.1     7.1479
> 1       417.9           100     14.5    4.1     6.9655             1       430.4           100     14.1    4.0     7.1733
> 1       427.7           100     14.2    4.2     7.1277             1       424.7           100     14.3    4.2     7.0778
> 5       2350.7          99      12.9    13.8    7.8355             5       2156.6          99      14.1    19.8    7.1886
> 5       2422.1          99      12.5    12.1    8.0735             5       2155.0          99      14.1    19.7    7.1835
> 5       2189.3          98      13.8    18.3    7.2977             5       2108.6          99      14.4    21.4    7.0285
> 10      4515.6          93      13.4    27.6    7.5261             10      4529.1          96      13.4    29.5    7.5486
> 10      4708.6          96      12.9    24.3    7.8477             10      4597.9          96      13.2    26.9    7.6631
> 10      4636.6          96      13.1    25.7    7.7276             10      5197.3          98      11.7    14.8    8.6621
> 20      8053.2          95      15.1    78.1    6.7110             20      9431.9          98      12.8    49.1    7.8599
> 20      8250.5          92      14.7    67.5    6.8754             20      7973.7          97      15.2    93.4    6.6447
> 20      8178.1          97      14.8    78.5    6.8151             20      8145.2          95      14.9    78.4    6.7876
> 40      17413.8         94      13.9    88.6    7.2557             40      16312.2         92      14.9    115.6   6.7968
> 40      16775.1         93      14.5    111.6   6.9896             40      17070.4         94      14.2    110.6   7.1127
> 40      16031.7         93      15.1    147.1   6.6799             40      17578.0         94      13.8    96.9    7.3241
> 80      33666.7         95      14.4    138.4   7.0139             80      33854.7         96      14.3    177.9   7.0531
> 80      33949.6         97      14.3    128.0   7.0728             80      34164.9         96      14.2    146.4   7.1177
> 80      35752.2         96      13.6    159.1   7.4484             80      33807.5         96      14.3    127.6   7.0432
> 160     74814.8         98      13.0    149.8   7.7932             160     75162.8         98      12.9    148.6   7.8295
> 160     74015.3         97      13.1    149.5   7.7099             160     74642.0         98      13.0    168.2   7.7752
> 160     73621.9         98      13.2    146.3   7.6689             160     75572.9         98      12.8    163.6   7.8722
> 320     139210.3        96      13.9    280.1   7.2505             320     139010.8        97      14.0    282.4   7.2401
> 320     135135.9        96      14.3    277.8   7.0383             320     139611.2        96      13.9    282.2   7.2714
> 320     139110.5        96      13.9    280.4   7.2453             320     138514.3        97      14.0    281.0   7.2143
> 640     223538.9        98      17.4    577.2   5.8213             640     224704.5        95      17.3    567.3   5.8517
> 640     224055.5        97      17.3    575.7   5.8348             640     222385.3        95      17.4    580.1   5.7913
> 640     225488.4        96      17.2    566.3   5.8721             640     225882.4        93      17.2    563.0   5.8824
> 
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at  http://www.tux.org/lkml/
>