Re: [PATCH] sched: Add SCHED_BGND (background) scheduling policy

[Peter Williams]

Con Kolivas wrote:
> some quick comments within code below.
>
> On Wednesday 05 July 2006 09:35, Peter Williams wrote:
> > @@ -761,8 +770,18 @@ static void set_load_weight(struct task_
> >  		else
> >  #endif
> >  			p->load_weight = RTPRIO_TO_LOAD_WEIGHT(p->rt_priority);
> > -	} else
> > -		p->load_weight = PRIO_TO_LOAD_WEIGHT(p->static_prio);
> > +	} else {
> > +		/*
> > +		 * Reduce the probability of a task escaping the background
> > +		 * due to load balancing leaving it on a lighly used CPU
> > +		 * Can't use zero as that would kill load balancing when only
> > +		 * background tasks are running.
> > +		 */
> > +		if (bgnd_task(p))
> > +			p->load_weight = LOAD_WEIGHT(MIN_TIMESLICE / 2 ? : 1);
>
> Why not just set it to 1 for all idleprio tasks? The granularity will be lost 
> at anything lower anyway and it avoids a more complex calculation.

I missed this one in my previous reply.  I agree, what you say makes 
sense.  I was in my "think too hard" mode and probably thinking 
(unnecessarily) about how it might effect the smoothed load calculations.

Peter
--
Peter Williams                                   pwil3058@xxxxxxxxxxxxxx

"Learning, n. The kind of ignorance distinguishing the studious."
 -- Ambrose Bierce
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