Re: [RFC PATCH 00/13] sched: Integrating Per-entity-load-tracking with the core scheduler

[Preeti U Murthy <preeti@linux.vnet.ibm.com>]

On 10/26/2012 06:37 PM, Ingo Molnar wrote:
> 
> * Peter Zijlstra <a.p.zijlstra@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