Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1525349 > unrolled thread

Re: [RFC v3 1/6] Track the active utilisation

Back to article view | Back to linux.kernel

This discussion starts older than the indexed window; earlier articles aren't shown. The article labeled Started by below is the oldest one visible, not the original post.

Contents

  Re: [RFC v3 1/6] Track the active utilisation Peter Zijlstra <peterz@infradead.org> - 2016-11-18 15:00 +0100
    Re: [RFC v3 1/6] Track the active utilisation luca abeni <luca.abeni@unitn.it> - 2016-11-18 16:10 +0100

#1525349 — Re: [RFC v3 1/6] Track the active utilisation

On Mon, Oct 24, 2016 at 04:06:33PM +0200, Luca Abeni wrote:

> @@ -498,6 +514,8 @@ static void update_dl_entity(struct sched_dl_entity *dl_se,
>  	struct dl_rq *dl_rq = dl_rq_of_se(dl_se);
>  	struct rq *rq = rq_of_dl_rq(dl_rq);
>  
> +	add_running_bw(dl_se, dl_rq);
> +
>  	if (dl_time_before(dl_se->deadline, rq_clock(rq)) ||
>  	    dl_entity_overflow(dl_se, pi_se, rq_clock(rq))) {
>  		dl_se->deadline = rq_clock(rq) + pi_se->dl_deadline;
> @@ -947,14 +965,19 @@ static void enqueue_task_dl(struct rq *rq, struct task_struct *p, int flags)
>  		return;
>  	}
>  
> +	if (p->on_rq == TASK_ON_RQ_MIGRATING)
> +		add_running_bw(&p->dl, &rq->dl);
> +
>  	/*
>  	 * If p is throttled, we do nothing. In fact, if it exhausted
>  	 * its budget it needs a replenishment and, since it now is on
>  	 * its rq, the bandwidth timer callback (which clearly has not
>  	 * run yet) will take care of this.
>  	 */
> -	if (p->dl.dl_throttled && !(flags & ENQUEUE_REPLENISH))
> +	if (p->dl.dl_throttled && !(flags & ENQUEUE_REPLENISH)) {
> +		add_running_bw(&p->dl, &rq->dl);
>  		return;
> +	}
>  
>  	enqueue_dl_entity(&p->dl, pi_se, flags);
>  

I realize the enqueue path is a bit of a maze, but this hurts my head.

Isn't there anything we can do to streamline this a bit?

Maybe move the add_running_bw() from update_dl_entity() to the
ENQUEUE_WAKEUP branch in enqueue_dl_entity()? Because that's what you
really want, isn't it? Its not actually related to recomputing the
absolute deadline.

> @@ -972,6 +995,12 @@ static void dequeue_task_dl(struct rq *rq, struct task_struct *p, int flags)
>  {
>  	update_curr_dl(rq);
>  	__dequeue_task_dl(rq, p, flags);
> +
> +	if (p->on_rq == TASK_ON_RQ_MIGRATING)
> +		sub_running_bw(&p->dl, &rq->dl);
> +
> +	if (flags & DEQUEUE_SLEEP)
> +		sub_running_bw(&p->dl, &rq->dl);
>  }

We could look at adding more enqueue/dequeue flags to streamline this a
bit, bit lets not do that now.

[toc] | [next] | [standalone]

#1525444

Hi Peter,

On Fri, 18 Nov 2016 14:55:54 +0100
Peter Zijlstra <peterz@infradead.org> wrote:

> On Mon, Oct 24, 2016 at 04:06:33PM +0200, Luca Abeni wrote:
> 
> > @@ -498,6 +514,8 @@ static void update_dl_entity(struct
> > sched_dl_entity *dl_se, struct dl_rq *dl_rq = dl_rq_of_se(dl_se);
> >  	struct rq *rq = rq_of_dl_rq(dl_rq);
> >  
> > +	add_running_bw(dl_se, dl_rq);
> > +
> >  	if (dl_time_before(dl_se->deadline, rq_clock(rq)) ||
> >  	    dl_entity_overflow(dl_se, pi_se, rq_clock(rq))) {
> >  		dl_se->deadline = rq_clock(rq) +
> > pi_se->dl_deadline; @@ -947,14 +965,19 @@ static void
> > enqueue_task_dl(struct rq *rq, struct task_struct *p, int flags)
> > return; }
> >  
> > +	if (p->on_rq == TASK_ON_RQ_MIGRATING)
> > +		add_running_bw(&p->dl, &rq->dl);
> > +
> >  	/*
> >  	 * If p is throttled, we do nothing. In fact, if it
> > exhausted
> >  	 * its budget it needs a replenishment and, since it now
> > is on
> >  	 * its rq, the bandwidth timer callback (which clearly has
> > not
> >  	 * run yet) will take care of this.
> >  	 */
> > -	if (p->dl.dl_throttled && !(flags & ENQUEUE_REPLENISH))
> > +	if (p->dl.dl_throttled && !(flags & ENQUEUE_REPLENISH)) {
> > +		add_running_bw(&p->dl, &rq->dl);
> >  		return;
> > +	}
> >  
> >  	enqueue_dl_entity(&p->dl, pi_se, flags);
> >    
> 
> I realize the enqueue path is a bit of a maze, but this hurts my head.
> 
> Isn't there anything we can do to streamline this a bit?
> 
> Maybe move the add_running_bw() from update_dl_entity() to the
> ENQUEUE_WAKEUP branch in enqueue_dl_entity()? Because that's what you
> really want, isn't it? Its not actually related to recomputing the
> absolute deadline.

Right... I'll change the code in this way. I am currently modifying
this code (because after Juri's review I realized that there is an
issue - see last email exchange with Juri); I'll make this change as
soon as the code stabilizes.


		Thanks,
			Luca

[toc] | [prev] | [standalone]

Back to top | Article view | linux.kernel

csiph-web