Subject: Re: [PATCH -v8][RFC] mutex: implement adaptive spinning
From: Peter Zijlstra <peterz@infradead.org>
To: Folkert van Heusden <folkert@vanheusden.com>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
In-Reply-To: <20090114114059.GA23674@vanheusden.com>
References: <1231774622.4371.96.camel@laptop>
	 <20090114114059.GA23674@vanheusden.com>
Content-Type: text/plain
Content-Transfer-Encoding: 7bit
Date: Wed, 14 Jan 2009 12:42:46 +0100
Message-Id: <1231933366.7141.28.camel@twins>
Mime-Version: 1.0
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 881
Lines: 17

On Wed, 2009-01-14 at 12:41 +0100, Folkert van Heusden wrote:
> > The key criteria for the busy wait is that the lock owner has to be running on
> > a (different) cpu. The idea is that as long as the owner is running, there is a
> > fair chance it'll release the lock soon, and thus we'll be better off spinning
> > instead of blocking/scheduling.
> 
> Won't this make Linux less "green"? (-> use more power since busy loops
> use more power than idle loops) If so, maybe it should be make
> configurable somewhere?

According to the 'race to idle' paradigm this would actually help making
it more green, since it increases throughput.
--
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/