Re: [patch v5 14/15] sched: power aware load balance

From: Alex Shi
Date: Thu Mar 21 2013 - 21:31:13 EST

On 03/21/2013 06:27 PM, Preeti U Murthy wrote:
>> > did you close all of background system services?
>> > In theory the rq->avg.runnable_avg_sum should be zero if there is no
>> > task a bit long, otherwise there are some bugs in kernel.
> Could you explain why rq->avg.runnable_avg_sum should be zero? What if
> some kernel thread ran on this run queue and is now finished? Its
> utilisation would be say x.How would that ever drop to 0,even if nothing
> ran on it later?

the value get from decay_load():
sa->runnable_avg_sum = decay_load(sa->runnable_avg_sum,
in decay_load it is possible to be set zero.

and /proc/sched_debug also approve this:

.tg_runnable_contrib : 0
.tg->runnable_avg : 50
.avg->runnable_avg_sum : 0
.avg->runnable_avg_period : 47507

Thanks Alex
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