linux-kernel - Re: [RFCv3 PATCH 28/48] sched: Use capacity_curr to cap utilization in get_cpu

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Message-ID: <20150323161400.GJ23123@twins.programming.kicks-ass.net>
Date:	Mon, 23 Mar 2015 17:14:00 +0100
From:	Peter Zijlstra <peterz@...radead.org>
To:	Morten Rasmussen <morten.rasmussen@....com>
Cc:	mingo@...hat.com, vincent.guittot@...aro.org,
	dietmar.eggemann@....com, yuyang.du@...el.com,
	preeti@...ux.vnet.ibm.com, mturquette@...aro.org, nico@...aro.org,
	rjw@...ysocki.net, juri.lelli@....com, linux-kernel@...r.kernel.org
Subject: Re: [RFCv3 PATCH 28/48] sched: Use capacity_curr to cap utilization
 in get_cpu_usage()

On Wed, Feb 04, 2015 at 06:31:05PM +0000, Morten Rasmussen wrote:

> @@ -4596,9 +4596,10 @@ static int get_cpu_usage(int cpu)
>  {
>  	unsigned long usage = cpu_rq(cpu)->cfs.utilization_load_avg;
>  	unsigned long blocked = cpu_rq(cpu)->cfs.utilization_blocked_avg;
> +	unsigned long capacity_curr = capacity_curr_of(cpu);
>  
> -	if (usage + blocked >= SCHED_LOAD_SCALE)
> -		return capacity_orig_of(cpu);
> +	if (usage + blocked >= capacity_curr)
> +		return capacity_curr;

It makes more sense to do return capacity_curr_of(), since that defers
the computation capacity_curr_of() does to the point where its actually
required, instead of making it unconditional.
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