From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934801AbXLQDAq (ORCPT ); Sun, 16 Dec 2007 22:00:46 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1764266AbXLQDAh (ORCPT ); Sun, 16 Dec 2007 22:00:37 -0500 Received: from py-out-1112.google.com ([64.233.166.179]:31447 "EHLO py-out-1112.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751785AbXLQDAg (ORCPT ); Sun, 16 Dec 2007 22:00:36 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:x-x-sender:reply-to:to:subject:message-id:mime-version:content-type; b=iWwE8oS7gyJU63JVLJhZ8SdgDH4QMTcvII6DF7TNhU2OSNWHgIxUdLVS5pFOqKx7l0PcbbO+j/ldjvotdIIQYoHORqqqPzESvIkQWLgym+mYbnZDph/qfWuKOlWYd6/FovceFm4vBUfrfEdblJ3H08fEoP0jf50FqYcaURb/6JI= Date: Sun, 16 Dec 2007 22:00:23 -0500 (EST) From: Parag Warudkar X-X-Sender: parag@mini.warudkars.net Reply-To: parag.warudkar@gmail.com To: linux-kernel@vger.kernel.org Subject: init_timer_deferrable conversion Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In my quest to get the wake-ups from idle per second down to bare minimum, I noticed 3 places in the kernel that could benefit from using init_timer_deferrable() instead of init_timer() - a) drivers/net/sky2.c - watchdog_timer. This was showing up high on Powertop's list of things that cause routine wakeups from idle. After converting to init_timer_deferrable() the wakeups went down and this one no longer shows up in powertop's list. 25% reduction. b) kernel/time/clocksource.c - watchdog_timer - same story as sky2.c c) net/core/neighbour.c - gc_timer - Most benefit from deferrable timer. I am running a kernel with above changes and haven't noticed any immediate problems and the wakeups-from-idle have gone down from 5-7 to mere 1-2 per second. Is there any reason not to make the above timers deferrable - corner cases, other side effects? If not then I will submit a patch. Thanks Parag