Messages in this thread | | | From | bsegall@google ... | Subject | Re: [PATCH] sched: put rq's sched_avg under CONFIG_FAIR_GROUP_SCHED | Date | Tue, 25 Feb 2014 11:55:50 -0800 |
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Dietmar Eggemann <dietmar.eggemann@arm.com> writes:
> On 25/02/14 13:16, Srikar Dronamraju wrote: >>> The struct sched_avg of struct rq is only used in case group >>> scheduling is enabled inside __update_tg_runnable_avg() to update >>> per-cpu representation of a task group. I.e. that there is no need to >>> maintain the runnable avg of a rq in the !CONFIG_FAIR_GROUP_SCHED case. >>> >>> This patch guards struct sched_avg of struct rq and >>> update_rq_runnable_avg() with CONFIG_FAIR_GROUP_SCHED. >>>
Reviewed-by: Ben Segall <bsegall@google.com>
If we ever decide to use runnable_avg_sum/period in balance or something, it's trivial enough to move it back, and there is no point in calculating unusued stats until then.
>> >> While this patch looks good, I see fields in sched_avg viz decay_count, >> last_runnable_update, load_avg_contrib only relevant to sched_entity. >> i.e they don't seem to be updated or used for rq->avg. Should we look at >> splitting sched_avg so that rq->avg doesn't have unwanted fields? > > Yes, AFAICS at least load_avg_contrib and decay_count are only relevant > for struct sched_entity whereas last_runnable_update is used in > __update_entity_runnable_avg() itself. > > By having struct sched_avg embedded into struct sched_entity and struct > rq, __update_entity_runnable_avg() and __update_tg_runnable_avg() can be > used on both and moreover, all current members of struct sched_avg > belong logically together. > > With this patch I was more interested in the fact that we do not have to > maintain the load avg for struct rq in a !CONFIG_FAIR_GROUP_SCHED system. >
Yeah, last_runnable_update and runnable_avg_sum/period are used, decay_count and load_avg_contrib could be moved to the se just fine, and won't cause any problems.
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