Re: Netperf UDP_STREAM regression due to not sending IPIs inttwu_queue()

[Mike Galbraith]

On Tue, 2012-10-02 at 07:51 +0100, Mel Gorman wrote: 
> I'm going through old test results to see could I find any leftover
> performance regressions that have not yet been fixed (most have at this point
> or at least changed in such a way to make a plain revert impossible). One
> major regression still left is with netperf UDP_STREAM regression. Bisection
> points the finger straight at 518cd623 (sched: Only queue remote wakeups
> when crossing cache boundaries).  Problem was introduced between 3.2 and
> 3.3, current kernel still sucks as the following results show.
> 
> NETPERF UDP
>                            3.3.0                 3.3.0                 3.6.0
>                          vanilla       revert-518cd623               vanilla
> Tput 64         328.38 (  0.00%)      436.58 ( 32.95%)      312.51 ( -4.83%)
> Tput 128        661.43 (  0.00%)      869.88 ( 31.52%)      625.70 ( -5.40%)
> Tput 256       1310.27 (  0.00%)     1724.45 ( 31.61%)     1243.65 ( -5.08%)
> Tput 1024      5466.85 (  0.00%)     6601.43 ( 20.75%)     4838.86 (-11.49%)
> Tput 2048     10885.95 (  0.00%)    12694.06 ( 16.61%)     9161.75 (-15.84%)
> Tput 3312     15930.33 (  0.00%)    19327.67 ( 21.33%)    14106.26 (-11.45%)
> Tput 4096     18025.47 (  0.00%)    22183.12 ( 23.07%)    16636.01 ( -7.71%)
> Tput 8192     30076.42 (  0.00%)    37280.86 ( 23.95%)    28575.84 ( -4.99%)
> Tput 16384    47742.12 (  0.00%)    56123.21 ( 17.55%)    46060.57 ( -3.52%)

Hm, 518cd623 fixed up the troubles I saw.  How exactly are you running
this?

-Mike

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/