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

[Peter Williams <pwil3058@bigpond.net.au>]

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@bigpond.net.au

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