Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261344AbUJXAwl (ORCPT ); Sat, 23 Oct 2004 20:52:41 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261352AbUJXAwk (ORCPT ); Sat, 23 Oct 2004 20:52:40 -0400 Received: from p508EF532.dip.t-dialin.net ([80.142.245.50]:61570 "EHLO oscar.local.net") by vger.kernel.org with ESMTP id S261372AbUJXAvp (ORCPT ); Sat, 23 Oct 2004 20:51:45 -0400 Date: Sun, 24 Oct 2004 02:51:42 +0200 From: Patrick Mau To: Linux Kernel Subject: Wrong calculation of load average ? Message-ID: <20041024005142.GA26209@oscar.prima.de> Reply-To: Patrick Mau Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.6+20040907i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2587 Lines: 81 Hallo everyone, I'm using a BK snapshot of linux 2.6 from today and have a strange problem with an otherwise stable SMP System. The calculated load average seems to "wrap around". The exact kernel version is: Linux oscar 2.6.10-2.6bk #1 SMP Sat Oct 23 16:45:50 CEST 2004 Below is the output of a looping 'cat /proc/loadavg'. The load drops to near-zero and then wraps to 1024. I already looked at the code involved but I am unable to see how this could happen. Timer interrupts are occuring on both CPU's: root@oscar] cat /proc/interrupts CPU0 CPU1 17159225 17408595 IO-APIC-edge timer The system is a dual P3 450Mhz (Asus P2B-DS), ACPI not compiled in, Preempt disabled, no regparams, but 4K stacks. 2.6.9 vanilla did not show these symptoms. System performance is not affected at all, but exim refuses to deliver mail ;) The gcc used is: [root@oscar] gcc --version gcc (GCC) 3.3.5 (Debian 1:3.3.5-1) I also tried a gcc 3.4 branch, but that didn't help either. This report is based on a kernel compiled with gcc 3.3 [root@oscar] /opt/gcc/bin/gcc --version gcc (GCC) 3.4.3 20041017 (prerelease) I'd appreciate any comments, Patrick [root@oscar] while true ; do cat /proc/loadavg ; sleep 10 ; done 112.95 1.94 2.54 1/139 25916 94.81 1.71 2.46 1/139 25918 79.47 1.49 2.38 1/139 25920 66.56 1.29 2.31 1/139 25925 55.56 1.08 2.23 1/139 25927 46.25 0.88 2.15 1/139 25929 38.59 0.74 2.09 1/139 25931 31.89 0.55 2.01 1/139 25933 26.21 0.36 1.94 1/139 25935 21.41 0.19 1.86 2/139 25937 17.35 0.02 1.79 1/139 25939 <--- here 13.92 1006.85 1.72 1/139 25941 11.01 973.53 1.64 1/139 25943 8.55 941.31 1.57 1/139 25945 6.46 910.15 1.50 1/139 25947 4.70 880.02 1.43 7/139 25949 3.28 850.89 1.37 1/139 25960 2.16 822.74 1.31 1/139 25970 1.14 795.50 1.25 1/142 25981 0.41 769.19 1.20 1/140 25983 <--- and here 941.66 743.72 1.13 1/158 26114 796.19 719.08 1.07 1/140 26164 673.09 695.25 1.01 1/140 26167 568.84 672.19 0.95 1/140 26169 480.61 649.89 0.88 1/140 26171 405.95 628.33 0.82 1/140 26173 342.77 607.48 0.76 1/140 26175 289.30 587.31 0.69 1/139 26177 244.14 567.82 0.64 1/139 26179 205.91 548.97 0.58 1/139 26181 173.48 530.73 0.52 1/139 26183 146.04 513.09 0.46 1/139 26185 122.82 496.03 0.40 1/139 26187 103.17 479.53 0.35 3/139 26189 86.77 463.63 0.30 1/139 26194 72.81 448.23 0.26 2/139 26196 60.85 433.31 0.20 1/139 26198 - 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/