From e0ee463c93c43b1657ad69cf2678ff5bf1b754fe Mon Sep 17 00:00:00 2001 From: Juri Lelli Date: Mon, 8 Feb 2021 08:35:54 +0100 Subject: sched/features: Distinguish between NORMAL and DEADLINE hrtick The HRTICK feature has traditionally been servicing configurations that need precise preemptions point for NORMAL tasks. More recently, the feature has been extended to also service DEADLINE tasks with stringent runtime enforcement needs (e.g., runtime < 1ms with HZ=1000). Enabling HRTICK sched feature currently enables the additional timer and task tick for both classes, which might introduced undesired overhead for no additional benefit if one needed it only for one of the cases. Separate HRTICK sched feature in two (and leave the traditional case name unmodified) so that it can be selectively enabled when needed. With: $ echo HRTICK > /sys/kernel/debug/sched_features the NORMAL/fair hrtick gets enabled. With: $ echo HRTICK_DL > /sys/kernel/debug/sched_features the DEADLINE hrtick gets enabled. Signed-off-by: Juri Lelli Signed-off-by: Luis Claudio R. Goncalves Signed-off-by: Daniel Bristot de Oliveira Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Link: https://lkml.kernel.org/r/20210208073554.14629-3-juri.lelli@redhat.com --- kernel/sched/deadline.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel/sched/deadline.c') diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index 6f377969fa71..aac3539aa0fe 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -1832,7 +1832,7 @@ static void set_next_task_dl(struct rq *rq, struct task_struct *p, bool first) if (!first) return; - if (hrtick_enabled(rq)) + if (hrtick_enabled_dl(rq)) start_hrtick_dl(rq, p); if (rq->curr->sched_class != &dl_sched_class) @@ -1895,7 +1895,7 @@ static void task_tick_dl(struct rq *rq, struct task_struct *p, int queued) * not being the leftmost task anymore. In that case NEED_RESCHED will * be set and schedule() will start a new hrtick for the next task. */ - if (hrtick_enabled(rq) && queued && p->dl.runtime > 0 && + if (hrtick_enabled_dl(rq) && queued && p->dl.runtime > 0 && is_leftmost(p, &rq->dl)) start_hrtick_dl(rq, p); } -- cgit v1.2.3