linux-kernel - Re: [RFC PATCH] Turn off the tick even when not idle

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Message-ID: <alpine.DEB.1.10.0909011554590.12112@V090114053VZO-1>
Date:	Tue, 1 Sep 2009 15:56:56 -0400 (EDT)
From:	Christoph Lameter <cl@...ux-foundation.org>
To:	Josh Triplett <josh@...htriplett.org>
cc:	linux-kernel@...r.kernel.org, Anton Blanchard <anton@...ba.org>,
	Tim Pepper <lnxninja@...ux.vnet.ibm.com>,
	Paul McKenney <paulmck@...ux.vnet.ibm.com>,
	John Stultz <johnstul@...ibm.com>,
	Jamey Sharp <jamey@...ilop.net>
Subject: Re: [RFC PATCH] Turn off the tick even when not idle

On Tue, 1 Sep 2009, Josh Triplett wrote:

> Please, give this patch a try and let me know what you think.

Looks quite good. The PNG shows more deterministic run time behavior.

> I'd like to work towards a patch which really can kill off the timer
> tick, making the kernel entirely event-driven and removing the polling
> that occurs in the timer tick.  I've reviewed everything the timer tick
> does, and every last bit of it could occur using an event-driven
> approach.

Good idea. Thought so for a long time. Thanks for working on it. Many of
the events can be deferred if nothing is happening in the system.
vm statistics, data expiration from caches etc. Not sure what to do about
the per cpu threads generated by various kernel subsystems though.

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