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From: Peter Zijlstra <peterz@infradead.org>
To: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Ingo Molnar <mingo@elte.hu>, Andi Kleen <andi@firstfloor.org>,
	Michel Lespinasse <walken@google.com>,
	Rik van Riel <riel@redhat.com>,
	Peter Hurley <peter@hurleysoftware.com>,
	Jason Low <jason.low2@hp.com>,
	Davidlohr Bueson <davidlohr@hp.com>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] sched: Fast idling of CPU when system is partially loaded
Date: Mon, 23 Jun 2014 20:50:06 +0200	[thread overview]
Message-ID: <20140623185006.GH13930@laptop.programming.kicks-ass.net> (raw)
In-Reply-To: <1403541645.2970.599.camel@schen9-DESK>

On Mon, Jun 23, 2014 at 09:40:45AM -0700, Tim Chen wrote:

> > @@ -5886,7 +5886,7 @@ static inline void update_sg_lb_stats(st
> >  
> >  		sgs->group_load += load;
> >  		sgs->sum_nr_running += rq->nr_running;
> > -		if (overload && rq->nr_running > 1)
> > +		if (rq->nr_running > 1)
> >  			*overload = true;
> >  #ifdef CONFIG_NUMA_BALANCING
> >  		sgs->nr_numa_running += rq->nr_numa_running;

> With this change, we'll be returning the overload indicator 
> that we don't use for non-root domains, which will be
> extra work in sg_lb_stats as it loops through each rq checking
> the nr_running to update the indicator.  I was hoping to avoid
> that if possible.

What extra work? We already load nr_running and overloaded is on-stack
and should be quite dirty already due to that.


  reply	other threads:[~2014-06-23 18:50 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-06-16 19:48 [PATCH v2] sched: Fast idling of CPU when system is partially loaded Tim Chen
2014-06-23  4:33 ` Jason Low
2014-06-23 12:52 ` Peter Zijlstra
2014-06-23 16:22   ` Andi Kleen
2014-06-23 16:44     ` Jason Low
2014-06-23 17:01       ` Tim Chen
2014-06-23 18:47     ` Peter Zijlstra
2014-06-23 16:40   ` Tim Chen
2014-06-23 18:50     ` Peter Zijlstra [this message]
2014-06-23 18:59       ` Tim Chen

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