Messages in this thread | | | From | Vincent Guittot <> | Date | Tue, 31 May 2022 18:32:25 +0200 | Subject | Re: [External] Re: [PATCH v3 2/2] sched/fair: optimize and simplify rq leaf_cfs_rq_list |
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On Tue, 31 May 2022 at 15:55, Chengming Zhou <zhouchengming@bytedance.com> wrote: > > Hi, > > On 2022/5/30 15:52, Vincent Guittot wrote: > > On Thu, 26 May 2022 at 12:40, Chengming Zhou > > <zhouchengming@bytedance.com> wrote: > >> > [...] > >> @@ -11257,9 +11218,10 @@ static inline bool vruntime_normalized(struct task_struct *p) > >> */ > >> static void propagate_entity_cfs_rq(struct sched_entity *se) > >> { > >> - struct cfs_rq *cfs_rq; > >> + struct cfs_rq *cfs_rq = cfs_rq_of(se); > >> > >> - list_add_leaf_cfs_rq(cfs_rq_of(se)); > >> + if (!throttled_hierarchy(cfs_rq)) > >> + list_add_leaf_cfs_rq(cfs_rq); > >> > >> /* Start to propagate at parent */ > >> se = se->parent; > >> @@ -11268,7 +11230,8 @@ static void propagate_entity_cfs_rq(struct sched_entity *se) > >> cfs_rq = cfs_rq_of(se); > >> > > > > you can break if the cfs is throttled because it's sched_entity has > > been dequeued. In this case we check if the cfs is throttled not if > > the hierarchy is throttled > > > > + if (cfs_rq_throttled(cfs_rq)) > > + break; > > > > This propagate part still make me confused. :-) > > I wonder if you think we should change like this: > > static void propagate_entity_cfs_rq(struct sched_entity *se) > { > struct cfs_rq *cfs_rq = cfs_rq_of(se); > > if (cfs_rq_throttled(cfs_rq)) --> break if cfs is throttled > return; > > if (!throttled_hierarchy(cfs_rq)) > list_add_leaf_cfs_rq(cfs_rq); > > /* Start to propagate at parent */ > se = se->parent; > > for_each_sched_entity(se) { > cfs_rq = cfs_rq_of(se); > > if (cfs_rq_throttled(cfs_rq)) --> break if cfs is throttled > break; > > update_load_avg(cfs_rq, se, UPDATE_TG); --> throttled cfs_rq->prop not updated > if (!throttled_hierarchy(cfs_rq)) > list_add_leaf_cfs_rq(cfs_rq); > } > } > > > > If I understand right, we should update_load_avg() until cfs_rq_throttled(), > including that throttled cfs_rq? So we can go on propagating when unthrottle. > > Maybe like this? > > static void propagate_entity_cfs_rq(struct sched_entity *se) > { > struct cfs_rq *cfs_rq = cfs_rq_of(se); > > if (cfs_rq_throttled(cfs_rq)) --> break if cfs is throttled > return; > > if (!throttled_hierarchy(cfs_rq)) > list_add_leaf_cfs_rq(cfs_rq); > > /* Start to propagate at parent */ > se = se->parent; > > for_each_sched_entity(se) { > cfs_rq = cfs_rq_of(se); > > update_load_avg(cfs_rq, se, UPDATE_TG); --> update throttled cfs_rq->prop
Yes, that looks correct. So we will ensure that the attach/detach is propagated down up to thethrottle cfs
> > if (cfs_rq_throttled(cfs_rq)) --> break if cfs is throttled > break; > > if (!throttled_hierarchy(cfs_rq)) > list_add_leaf_cfs_rq(cfs_rq); > } > } > > > Thanks! > > > >> update_load_avg(cfs_rq, se, UPDATE_TG); > >> - list_add_leaf_cfs_rq(cfs_rq); > >> + if (!throttled_hierarchy(cfs_rq)) > >> + list_add_leaf_cfs_rq(cfs_rq); > >> } > >> } > >> #else > >> -- > >> 2.36.1 > >>
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