Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751325AbVLEGZG (ORCPT ); Mon, 5 Dec 2005 01:25:06 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751340AbVLEGZG (ORCPT ); Mon, 5 Dec 2005 01:25:06 -0500 Received: from adelphi.physics.adelaide.edu.au ([129.127.102.1]:59348 "EHLO adelphi.physics.adelaide.edu.au") by vger.kernel.org with ESMTP id S1751325AbVLEGZE (ORCPT ); Mon, 5 Dec 2005 01:25:04 -0500 From: Jonathan Woithe Message-Id: <200512050626.jB56Qf1o032238@auster.physics.adelaide.edu.au> Subject: 2.6.14-rt21: slow-running clock To: linux-kernel@vger.kernel.org Date: Mon, 5 Dec 2005 16:56:40 +1030 (CST) Cc: jwoithe@physics.adelaide.edu.au (Jonathan Woithe) X-Mailer: ELM [version 2.5 PL6] MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1256 Lines: 26 Hi all When running Ingo's 2.6.14-rt21 (and in fact rt kernels back to at least 2.6.13-rc days), the clock on my i915-based laptop runs slow. The degree of slowness appears directly related to how busy the machine is. If it is just sitting around doing very little the time is kept rather well. However, as soon as the load increases the RTC and system time diverge significantly. For example, running jackd for 2 minutes results in the system time loosing as much as 20 seconds compared to the CMOS RTC. Processes doing HDD I/O also seem to affect the system time similarly. Selectively disabling different timer-related kernel options does not make any difference. However, the clock seems fine under vanilla 2.6.14, suggesting an issue somewhere in the rt patches. HZ is set to 1000 on this machine in case that makes any difference. I'm happy to apply patches and run tests to try to narrow the problem down if it will help. Please CC me replys to ensure I see them. Thanks and regards jonathan - 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/