[RFC PATCH 00/13] sched: Integrating Per-entity-load-tracking with the core scheduler
Preeti U Murthy
preeti at linux.vnet.ibm.com
Fri Oct 26 23:36:07 EDT 2012
On 10/26/2012 06:37 PM, Ingo Molnar wrote:
>
> * Peter Zijlstra <a.p.zijlstra at chello.nl> wrote:
>
>> [...]
>>
>> So a sane series would introduce maybe two functions:
>> cpu_load() and task_load() and use those where we now use
>> rq->load.weight and p->se.load.weight for load balancing
>> purposes. Implement these functions using those two
>> expression. So effectively this patch is a NOP.
>>
>> Secondly, switch these two functions over to the per-task
>> based averages.
>>
>> Tada! all done. The load balancer will then try and equalize
>> effective load instead of instant load.
>>
>> It will do the 3x10% vs 100% thing correctly with just those
>> two patches. Simply because it will report a lower cpu-load
>> for the 3x10% case than it will for the 100% case, no need to
>> go fudge about in the load-balance internals.
>>
>> Once you've got this correctly done, you can go change
>> balancing to better utilize the new metric, like use the
>> effective load instead of nr_running against the capacity and
>> things like that. But for every such change you want to be
>> very careful and run all the benchmarks you can find -- in
>> fact you want to do that after the 2nd patch too.
>
> If anyone posted that simple two-patch series that switches over
> to the new load metrics I'd be happy to test the performance of
> those.
>
> Having two parallel load metrics is really not something that we
> should tolerate for too long.
>
> Thanks,
>
> Ingo
>
Right Ingo.I will incorporate this approach and post out very soon.
Thank you
Regards
Preeti
More information about the linux-arm-kernel
mailing list