Re: [RFC PATCH 0/2] sched: simplify the select_task_rq_fair()

[Mike Galbraith]

On Mon, 2013-01-21 at 15:34 +0800, Michael Wang wrote: 
> On 01/21/2013 02:42 PM, Mike Galbraith wrote:
> > On Mon, 2013-01-21 at 13:07 +0800, Michael Wang wrote:
> > 
> >> That seems like the default one, could you please show me the numbers in
> >> your datapoint file?
> > 
> > Yup, I do not touch the workfile.  Datapoints is what you see in the
> > tabulated result...
> > 
> > 1
> > 1
> > 1
> > 5
> > 5
> > 5
> > 10
> > 10
> > 10
> > ...
> > 
> > so it does three consecutive runs at each load level.  I quiesce the
> > box, set governor to performance, echo 250 32000 32 4096
> >> /proc/sys/kernel/sem, then ./multitask -nl -f, and point it
> > at ./datapoints.
> 
> I have changed the "/proc/sys/kernel/sem" to:
> 
> 2000    2048000 256     1024
> 
> and run few rounds, seems like I can't reproduce this issue on my 12 cpu
> X86 server:
> 
> 	prev		post
> Tasks    jobs/min  	jobs/min
>     1      508.39    	506.69
>     5     2792.63   	2792.63
>    10     5454.55   	5449.64
>    20    10262.49  	10271.19
>    40    18089.55  	18184.55
>    80    28995.22  	28960.57
>   160    41365.19  	41613.73
>   320    53099.67  	52767.35
>   640    61308.88  	61483.83
>  1280    66707.95  	66484.96
>  2560    69736.58  	69350.02
> 
> Almost nothing changed...I would like to find another machine and do the
> test again later.

Hm.  Those numbers look odd.  Ok, I've got 8 more cores, but your hefty
load throughput is low.  When I look low end numbers, seems your cores
are more macho than my 2.27 GHz EX cores, so it should have been a lot
closer.  Oh wait, you said "12 cpu".. so 1 6 core package + HT?  This
box is 2 NUMA nodes (was 4), 2 (was 4) 10 core packages + HT.

-Mike

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