Re: [patch v4 01/18] sched: set SD_PREFER_SIBLING on MC domain toreduce a domain level

From: Alex Shi
Date: Sat Feb 16 2013 - 00:16:48 EST


On 02/15/2013 08:38 PM, Peter Zijlstra wrote:
> On Wed, 2013-02-13 at 21:22 +0800, Alex Shi wrote:
>> No, the flags set on MC/CPU domain, but is checked in their parents
>> balancing, like in NUMA domain.
>> Without the flag, will cause NUMA domain imbalance. like on my 2
>> sockets
>> NHM EP: 3 of 4 tasks were assigned on socket 0(lcpu, 10, 12, 14)
>>
>> In this case, update_sd_pick_busiest() need a reduced group_capacity
>> to
>> return true:
>> if (sgs->sum_nr_running > sgs->group_capacity)
>> return true;
>> then numa domain balancing get chance to start.
>
> Ah, indeed. Its always better to include such 'obvious' problems in the
> changelog :-)
>

got it. :)
how about the following commit log and patch:

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