From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S267506AbUHPKM5 (ORCPT ); Mon, 16 Aug 2004 06:12:57 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S267510AbUHPKM4 (ORCPT ); Mon, 16 Aug 2004 06:12:56 -0400 Received: from gw-oleane.hubxpress.net ([81.80.52.129]:23505 "EHLO yoda.hubxpress.net") by vger.kernel.org with ESMTP id S267506AbUHPKMp (ORCPT ); Mon, 16 Aug 2004 06:12:45 -0400 From: "Sylvain COUTANT" To: "'Marcelo Tosatti'" Cc: , , Subject: RE: High CPU usage (up to server hang) under heavy I/O load Date: Mon, 16 Aug 2004 12:11:48 +0200 Organization: ILLICOM MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit X-Mailer: Microsoft Office Outlook, Build 11.0.5510 In-Reply-To: <20040813162018.GB29292@logos.cnet> X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1441 Thread-Index: AcSBXhRCgfKy+w6USDGgDhs63iBGowCGXQ1g Message-Id: <20040816101241.6315F2FC2C@illicom.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi Marcello, > You want to try this The server now runs 2.4.26 with the patch applied for about two hours. I have triggered backups so that it is a little bit stressed. My first feeling is something changed. Once the whole physical memory has been in use by the kernel, I saw some load problems rising (as before), but the server did not hang (as before ;-) and system load has gone down smoothly (took about one or two minutes). Now it looks stable under medium I/O load. I'll give it more stress next night and I'll report the behaviour here. However, kswapd is still a major CPU eater : 5 minutes of CPU time consumed since the reboot (2 hours). kupdated is at 1 minute and bdflush is 12 seconds. /proc/sys/vm are boot time standard settings with no change. Actual system load is near 4 for 15 minutes average, which I consider very bad result regarding currently running application. I believe I should be near 1 ... Do you think I could achieve better results (smoother operations) by tweaking those /proc/sys/vm settings ? Regards, Sylvain.