| Date | Sat, 10 Jun 2023 14:34:04 +0800 | From | Chen Yu <> | Subject | Re: [PATCH 11/15] sched/eevdf: Better handle mixed slice length |
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On 2023-05-31 at 13:58:50 +0200, Peter Zijlstra wrote: > In the case where (due to latency-nice) there are different request > sizes in the tree, the smaller requests tend to be dominated by the > larger. Also note how the EEVDF lag limits are based on r_max. > > Therefore; add a heuristic that for the mixed request size case, moves > smaller requests to placement strategy #2 which ensures they're > immidiately eligible and and due to their smaller (virtual) deadline > will cause preemption. > > NOTE: this relies on update_entity_lag() to impose lag limits above > a single slice. > > Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> > --- > kernel/sched/fair.c | 30 ++++++++++++++++++++++++++++++ > kernel/sched/features.h | 1 + > kernel/sched/sched.h | 1 + > 3 files changed, 32 insertions(+) > > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -642,6 +642,7 @@ avg_vruntime_add(struct cfs_rq *cfs_rq, > s64 key = entity_key(cfs_rq, se); > > cfs_rq->avg_vruntime += key * weight; > + cfs_rq->avg_slice += se->slice * weight; > cfs_rq->avg_load += weight; > } > > @@ -652,6 +653,7 @@ avg_vruntime_sub(struct cfs_rq *cfs_rq, > s64 key = entity_key(cfs_rq, se); > > cfs_rq->avg_vruntime -= key * weight; > + cfs_rq->avg_slice -= se->slice * weight; > cfs_rq->avg_load -= weight; > } > > @@ -4908,6 +4910,21 @@ static inline void update_misfit_status( > > #endif /* CONFIG_SMP */ > > +static inline bool > +entity_has_slept(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) > +{ > + u64 now; > + > + if (!(flags & ENQUEUE_WAKEUP)) > + return false; > + > + if (flags & ENQUEUE_MIGRATED) > + return true; > + > + now = rq_clock_task(rq_of(cfs_rq)); > + return (s64)(se->exec_start - now) >= se->slice; > +} A minor question, should it be now - se->exec_start ? (se->exec_start - now) is always negetive on local wakeup?
thanks, Chenyu
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