Re: [PATCH V2] sched: Improve load balancing in the presence of idle CPUs

From: Wanpeng Li
Date: Fri Mar 27 2015 - 00:42:16 EST


Hi Preeti,
On Fri, Mar 27, 2015 at 10:03:21AM +0530, Preeti U Murthy wrote:
>is set to CPU_NOT_IDLE.
>
>""
>idle = idle_cpu(cpu) ? CPU_IDLE : CPU_NOT_IDLE;
>
>And,
>
>When nohz_idle_balance() is called, the state of idle of ILB CPU is
>checked before proceeding with load balancing on idle CPUs.
>
>""
>
>if (idle != CPU_IDLE ||
> !test_bit(NOHZ_BALANCE_KICK, nohz_flags(this_cpu)))
> goto end;
>

This idle is the one caculated in run_rebalance_domains() before invoke
rebalance_domains(), rebalance_domains() cannot modify this local
variable.

Regards,
Wanpeng Li

>You see that nohz idle balancing gets aborted.
>
>Regards
>Preeti U Murthy
>
>
>
>>
>> Regards,
>> Wanpeng Li
>>
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