Re: [PATCH 06/16] sched: SCHED_DEADLINE push and pull logic

[Juri Lelli]

On 04/11/2012 06:21 PM, Steven Rostedt wrote:
> On Fri, 2012-04-06 at 09:14 +0200, Juri Lelli wrote:
>
> >   /*
> >    * Only called when both the current and waking task are -deadline
> >    * tasks.
> > @@ -487,8 +819,20 @@ static void yield_task_dl(struct rq *rq)
> >   static void check_preempt_curr_dl(struct rq *rq, struct task_struct *p,
> >   				  int flags)
> >   {
> > -	if (dl_time_before(p->dl.deadline, rq->curr->dl.deadline))
> > +	if (dl_time_before(p->dl.deadline, rq->curr->dl.deadline)) {
> >   		resched_task(rq->curr);
> > +		return;
> > +	}
> > +
> > +#ifdef CONFIG_SMP
> > +	/*
> > +	 * In the unlikely case current and p have the same deadline
> > +	 * let us try to decide what's the best thing to do...
> > +	 */
> > +	if ((s64)(p->dl.deadline - rq->curr->dl.deadline) == 0&&
> > +	    !need_resched())
>
> OK, maybe I'm thick. But how is:
>
>    (s64)(p->dl.deadline - rq->curr->dl.deadline) == 0
>
> Better than:
>
>    p->dl.deadline == rq->curr->dl.deadline
>
> ?

I agree, will change.

> > +		check_preempt_equal_dl(rq, p);
> > +#endif /* CONFIG_SMP */
> >   }


Thanks,

- Juri
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