Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757296AbZANUD1 (ORCPT ); Wed, 14 Jan 2009 15:03:27 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753836AbZANUDR (ORCPT ); Wed, 14 Jan 2009 15:03:17 -0500 Received: from arroyo.ext.ti.com ([192.94.94.40]:34319 "EHLO arroyo.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751744AbZANUDQ convert rfc822-to-8bit (ORCPT ); Wed, 14 Jan 2009 15:03:16 -0500 From: "Hunter, Jon" To: "linux-kernel@vger.kernel.org" Date: Wed, 14 Jan 2009 14:03:09 -0600 Subject: [RFC] Dynamic Tick and Deferrable Timer Support Thread-Topic: [RFC] Dynamic Tick and Deferrable Timer Support Thread-Index: Acl2gx9jeqfIjHueTQaihVCgLJMoAQ== Message-ID: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: acceptlanguage: en-US Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1950 Lines: 42 Hello All, I have been working to maximise the kernel sleep time on an embedded device by utilising the dynamic tick and deferrable timer features. During the course of this work I found that although timers were configured as deferrable, only timers for time interval tv1 were actually being deferred. Reviewing the deferrable timer patch [1], it does appear that the code is written to only defer timers for interval tv1. Therefore, I wanted to ask if this is intentional or not? I have applied the below patch to defer all deferrable timers regardless of interval and so far it is working on the embedded device. I wanted to share this in case this could be something that could be applied to the mainline. Please excuse any foolish mistakes I may have made here as this is my first post to your mailing list. Any feedback you could offer would be appreciated. Cheers Jon [1] Deferrable timer patch: http://marc.info/?l=linux-kernel&m=117512286417320&w=2 Signed-off-by: Jon Hunter --- kernel/timer.c | 3 +++ 1 files changed, 3 insertions(+), 0 deletions(-) diff --git a/kernel/timer.c b/kernel/timer.c index dee3f64..76a3ac6 100644 --- a/kernel/timer.c +++ b/kernel/timer.c @@ -930,6 +930,9 @@ cascade: index = slot = timer_jiffies & TVN_MASK; do { list_for_each_entry(nte, varp->vec + slot, entry) { + if (tbase_get_deferrable(nte->base)) + continue; + found = 1; if (time_before(nte->expires, expires)) expires = nte->expires; -- 1.5.6.3 -- 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/