Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751689AbXBVQmO (ORCPT ); Thu, 22 Feb 2007 11:42:14 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751692AbXBVQmO (ORCPT ); Thu, 22 Feb 2007 11:42:14 -0500 Received: from pentafluge.infradead.org ([213.146.154.40]:38683 "EHLO pentafluge.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751686AbXBVQmN (ORCPT ); Thu, 22 Feb 2007 11:42:13 -0500 Subject: Re: NO_HZ: timer interrupt stuck [Re: Linux 2.6.21-rc1] From: Arjan van de Ven To: Pierre Ossman Cc: tglx@linutronix.de, Jan Engelhardt , Luca Tettamanti , linux-kernel@vger.kernel.org In-Reply-To: <45DDC488.1080008@drzeus.cx> References: <20070221230409.GA1158@dreamland.darkstar.lan> <1172099859.25076.132.camel@localhost.localdomain> <1172150712.3531.265.camel@laptopd505.fenrus.org> <45DDA43A.4030509@drzeus.cx> <1172154034.3531.270.camel@laptopd505.fenrus.org> <45DDADEB.3030309@drzeus.cx> <45DDB31C.8070306@drzeus.cx> <1172160024.25076.188.camel@localhost.localdomain> <45DDC488.1080008@drzeus.cx> Content-Type: text/plain Organization: Intel International BV Date: Thu, 22 Feb 2007 17:42:06 +0100 Message-Id: <1172162526.3531.275.camel@laptopd505.fenrus.org> Mime-Version: 1.0 X-Mailer: Evolution 2.8.2.1 (2.8.2.1-3.fc6) Content-Transfer-Encoding: 7bit X-SRS-Rewrite: SMTP reverse-path rewritten from by pentafluge.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1174 Lines: 31 On Thu, 2007-02-22 at 17:27 +0100, Pierre Ossman wrote: > Thomas Gleixner wrote: > > > > Here is the reason. The local APIC stops working in C3 state and we fall > > back to the PIT in that case. Not really exciting for dynticks, but the > > only way to keep the system alive. There is a patch coming up from > > Intel, which finds out how to use HPET even if it is not enabled by the > > BIOS. This will still end up on IRQ#0, but will give way longer idle > > sleeps than the PIT. > > > > > > So then the next two questions are; is it possible to disable C3 yeah there is a commandline thingy for it > and is > it a net power gain to get rid of the wakeups in favor of having C3. no; c3 saves a TON more power. you can try enabling HPET in your BIOS... -- if you want to mail me at work (you don't), use arjan (at) linux.intel.com Test the interaction between Linux and your BIOS via http://www.linuxfirmwarekit.org - 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/