Messages in this thread | | | Date | Thu, 13 Nov 2014 09:37:32 +0000 | From | Juri Lelli <> | Subject | Re: [PATCH 2/2] sched/deadline: fix start high-res preemption tick for a non-running task |
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Hi,
not sure I understand what the problem is here.
On 11/11/14 01:52, Wanpeng Li wrote: > Queued ticks are scheduled to match the budget, which means the budget > is overall consumed and the dl task should be throttled.
... enforce the budget? It means that when the budget is consumed the task has to be throttled...
> Dl task will > be replenished immediately if fail to start a dl timer. > > However, the curr maybe not the left most dl task in the rb tree any > more after this immediately replenished and reschedule is needed. > Start high-res preemption tick for this upcoming rescheduled dl task > is not correct. >
So, the task that is going to preempt curr is picked by pick_next_task_dl(), that correctly starts the hrtick for this new task.
Maybe you can add more information about what you are seeing? A callpath maybe?
Thanks,
- Juri
> This patch fix it by not starting high-res preemption tick for a > non-running dl task. > > Signed-off-by: Wanpeng Li <wanpeng.li@linux.intel.com> > --- > kernel/sched/deadline.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c > index 56674f6..2a6a5bb 100644 > --- a/kernel/sched/deadline.c > +++ b/kernel/sched/deadline.c > @@ -1090,7 +1090,8 @@ static void task_tick_dl(struct rq *rq, struct task_struct *p, int queued) > { > update_curr_dl(rq); > > - if (hrtick_enabled(rq) && queued && p->dl.runtime > 0) > + if (hrtick_enabled(rq) && queued && p->dl.runtime > 0 && > + is_leftmost(p, &rq->dl)) > start_hrtick_dl(rq, p); > } > >
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