Re: [PATCH v8 1/4] sched: Remove rq's runnable avg

[Dietmar Eggemann]

Hi Yuyang,

On 15/06/15 20:26, Yuyang Du wrote:
> The current rq->avg is not used at all since its merge into kernel,
> and the code is in the scheduler's hot path, so remove it.

are you sure that this is the case? I was always under the impression
that w/ CONFIG_FAIR_GROUP_SCHED=y rq->avg (runnable_avg_sum, avg_period)
is used to calculate contrib in __update_tg_runnable_avg() for the root
group (cfs_rq->tg->css.id = 1).

On tg's w/ cfs_rq->tg->css.id > 1, se->avg (runnable_avg_sum,
avg_period) is used instead but we simply don't have a tg related se for
the root group. IMHO, that's why we have this rq::avg.

I understand that w/ the second patch in your series you don't need
rq::avg any more.

[...]

-- Dietmar

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