Date: Wed, 2 May 2007 20:15:33 +0200
From: Ingo Molnar <mingo@elte.hu>
To: William Lee Irwin III <wli@holomorphy.com>
Cc: Srivatsa Vaddagiri <vatsa@in.ibm.com>, Ting Yang <tingy@cs.umass.edu>,
       linux-kernel@vger.kernel.org
Subject: Re: [patch] CFS scheduler, -v8
Message-ID: <20070502181533.GA19479@elte.hu>
References: <20070501212223.GA29867@elte.hu> <4637FE0A.7090405@cs.umass.edu> <20070502173634.GA11308@in.ibm.com> <20070502174829.GX19966@holomorphy.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20070502174829.GX19966@holomorphy.com>
User-Agent: Mutt/1.4.2.2i
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1075
Lines: 24


* William Lee Irwin III <wli@holomorphy.com> wrote:

> > There is also p->wait_runtime which is taken into account when 
> > calculating p->fair_key. So if p3 had waiting in runqueue for long 
> > before, it can get to run quicker than 10ms later.
> 
> Virtual time is time from the task's point of view, which it has spent 
> executing. ->wait_runtime is a device to subtract out time spent on 
> the runqueue but not running from what would otherwise be virtual time 
> to express lag, whether deliberately or coincidentally. [...]

CFS is in fact _built around_ the ->wait_runtime metric (which, as its 
name suggests already, expresses the precise lag a task observes 
relative to 'ideal' fair execution), so what exactly makes you suspect 
that this property of the ->wait_runtime metric might be 'coincidental'? 
;-)

	Ingo
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/