Messages in this thread | | | From | 禹舟键 <> | Date | Mon, 11 Feb 2019 10:43:18 +0800 | Subject | Re: [PATCH] sched/debug: Show intergroup and hierarchy sum wait time of a task group |
| |
Hi Peter > The problem I have with this is that it will make schedstats even more expensive :/
I think the overhead for accounting hierarchy wait time is just the same as cpuacct.usage. If the performance overhead is low enough(< 1%), is it acceptable?
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 :/
| |