Messages in this thread | | | From | 禹舟键 <> | Date | Mon, 25 Feb 2019 11:29:46 +0800 | Subject | Re: [PATCH] sched/debug: Show intergroup and hierarchy sum wait time of a task group |
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PING
禹舟键 <ufo19890607@gmail.com> 于2019年2月19日周二 上午10:15写道: > > PING > > 禹舟键 <ufo19890607@gmail.com> 于2019年2月12日周二 上午11:14写道: > > > > Hi, Peter > > I think hierarchy wait time for task groups is worth accounting > > despite with a little extra overhead. Because we can evaluate task > > groups' condition with a more direct metric. We cannot get the real > > situation just with some general metrics, like idle or loadavg, since > > their value is decreased with the elapse of time. So, I think general > > metrics cannot satisify the request for task groups. > > > > Thanks > > Yuzhoujian > > > > > > Peter Zijlstra <peterz@infradead.org> 于2019年2月7日周四 上午1:19写道: > > > > > > On Wed, Jan 23, 2019 at 05:46:56PM +0800, ufo19890607@gmail.com wrote: > > > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > > > > index e2ff4b6..35e89ca 100644 > > > > --- a/kernel/sched/fair.c > > > > +++ b/kernel/sched/fair.c > > > > @@ -858,6 +858,19 @@ static void update_curr_fair(struct rq *rq) > > > > } > > > > > > > > static inline void > > > > +update_hierarchy_wait_sum(struct sched_entity *se, > > > > + u64 delta_wait) > > > > +{ > > > > + for_each_sched_entity(se) { > > > > + struct cfs_rq *cfs_rq = cfs_rq_of(se); > > > > + > > > > + if (cfs_rq->tg != &root_task_group) > > > > + __schedstat_add(cfs_rq->hierarchy_wait_sum, > > > > + delta_wait); > > > > + } > > > > +} > > > > + > > > > +static inline void > > > > update_stats_wait_end(struct cfs_rq *cfs_rq, struct sched_entity *se) > > > > { > > > > struct task_struct *p; > > > > @@ -880,6 +893,7 @@ static void update_curr_fair(struct rq *rq) > > > > return; > > > > } > > > > trace_sched_stat_wait(p, delta); > > > > + update_hierarchy_wait_sum(se, delta); > > > > } > > > > > > > > __schedstat_set(se->statistics.wait_max, > > > > > > The problem I have with this is that it will make schedstats even more > > > expensive :/
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