From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1422749AbXBAKS5 (ORCPT ); Thu, 1 Feb 2007 05:18:57 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1422764AbXBAKS5 (ORCPT ); Thu, 1 Feb 2007 05:18:57 -0500 Received: from smtp7-g19.free.fr ([212.27.42.64]:47400 "EHLO smtp7-g19.free.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1422749AbXBAKSz (ORCPT ); Thu, 1 Feb 2007 05:18:55 -0500 Message-ID: <45C1BE5C.9050001@free.fr> Date: Thu, 01 Feb 2007 11:18:04 +0100 From: John User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.8.0.8) Gecko/20061108 SeaMonkey/1.0.6 MIME-Version: 1.0 To: linux-kernel@vger.kernel.org CC: tglx@timesys.com, mingo@elte.hu, johnstul@us.ibm.com, akpm@osdl.org, shill@free.fr Subject: Re: One-shot high-resolution POSIX timer periodically late References: In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org [ Same player shoot again. Fix address. ] Ingo Molnar wrote: > John wrote: > >> John Stultz wrote: >> >>> Also do check the -rt tree as Ingo suggested. I mis-read your earlier >>> email and thought you were running it. >> >> I've been pulling my hair over a related issue for the past two days. >> >> (I think I may be tickling a -hrt bug...) >> >> I'm working with 2.6.18.6 + patch-2.6.18-rt7 > > 2.6.18-rt7 is pretty old, do you see the problem in 2.6.20-rc6-rt5 too? Ingo, Thomas, I cannot reproduce in 2.6.20-rc6-rt6, but it is not strictly an apples-to-apples comparison because I get a tsc clocksource in 2.6.20-rc6-rt6, and an acpi_pm clocksource in 2.6.18.6-rt7. Here are the relevant parts of my boot messages: Linux version 2.6.18.6-rt7 ACPI: PM-Timer IO Port: 0x4008 Clock event device pit configured with caps set: 07 Time: acpi_pm clocksource has been installed. Clock event device pit configured with caps set: 08 Switched to high resolution mode on CPU 0 Linux version 2.6.20-rc6-rt6 ACPI: PM-Timer IO Port: 0x4008 Time: tsc clocksource has been installed. (pit and acpi_pm have disappeared from 2.6.20-rc6-rt6) The -rt patch set looks great, but I am somewhat hesitant to use it. It seems it is only updated for the latest kernel version available. Or am I mistaken? In other words, once 2.6.20 is released, and work starts on 2.6.21, if a bug is discovered in -rt, the fix will not be back-ported to the 2.6.20.x (and 2.6.19.x, and 2.6.18.x, etc) patch set? NB: I do need high-resolution timers, but, at the same time, I'm not very comfortable living on the bleeding edge, where new bugs and regressions might not get caught in release candidates. (I work on an industrial project where continuous operation is a requirement.) Regards.