linux-kernel - Re: [PATCH v4 2/3] sched: Consider max cost of idle balance per sched domain

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Message-ID: <20130830094657.GD10002@twins.programming.kicks-ass.net>
Date:	Fri, 30 Aug 2013 11:46:57 +0200
From:	Peter Zijlstra <peterz@...radead.org>
To:	Jason Low <jason.low2@...com>
Cc:	mingo@...hat.com, linux-kernel@...r.kernel.org, efault@....de,
	pjt@...gle.com, preeti@...ux.vnet.ibm.com,
	akpm@...ux-foundation.org, mgorman@...e.de, riel@...hat.com,
	aswin@...com, scott.norton@...com, srikar@...ux.vnet.ibm.com
Subject: Re: [PATCH v4 2/3] sched: Consider max cost of idle balance per
 sched domain

On Thu, Aug 29, 2013 at 01:05:35PM -0700, Jason Low wrote:
> @@ -5299,14 +5300,29 @@ void idle_balance(int this_cpu, struct rq *this_rq)
>  	for_each_domain(this_cpu, sd) {
>  		unsigned long interval;
>  		int balance = 1;
> +		u64 t0, domain_cost, max = 5*sysctl_sched_migration_cost;
>  
>  		if (!(sd->flags & SD_LOAD_BALANCE))
>  			continue;
>  
> +		if (this_rq->avg_idle < curr_cost + sd->max_newidle_lb_cost)
> +			break;
> +
>  		if (sd->flags & SD_BALANCE_NEWIDLE) {
> +			t0 = sched_clock_cpu(smp_processor_id());
> +
>  			/* If we've pulled tasks over stop searching: */
>  			pulled_task = load_balance(this_cpu, this_rq,
>  						   sd, CPU_NEWLY_IDLE, &balance);
> +
> +			domain_cost = sched_clock_cpu(smp_processor_id()) - t0;
> +			if (domain_cost > max)
> +				domain_cost = max;
> +
> +			if (domain_cost > sd->max_newidle_lb_cost)
> +				sd->max_newidle_lb_cost = domain_cost;
> +
> +			curr_cost += domain_cost;
>  		}
>  
>  		interval = msecs_to_jiffies(sd->balance_interval);

I did an s/smp_processor_id()/this_cpu/ on that.
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