From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Wed, 30 Oct 2002 15:51:48 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Wed, 30 Oct 2002 15:51:47 -0500 Received: from coxeter.math.toronto.edu ([128.100.68.3]:35264 "EHLO coxeter.math.toronto.edu") by vger.kernel.org with ESMTP id ; Wed, 30 Oct 2002 15:51:45 -0500 Date: Wed, 30 Oct 2002 15:58:03 -0500 From: marco To: linux-kernel@vger.kernel.org Subject: Crazy idle values with 2.4.18-17.7.x Message-ID: <20021030155803.F189806@math.utoronto.ca> Reply-To: marco@reimeika.ca Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hello, Apologies in advance if Red Hat kernels should not be discussed here (pointers are appreciated). I've recently upgraded to kernel-2.4.18-17.7.x.athlon.rpm (from kernel-2.4.18-10.athlon.rpm) and I've noticed a problem with the CPU idle %. Here is an example of what happens when running "top": 10:37am up 8 days, 22:02, 9 users, load average: 1.00, 1.01, 1.00 89 processes: 81 sleeping, 7 running, 1 zombie, 0 stopped CPU states: 0.1% user, 0.1% system, 99.8% nice, 857278.7% idle Mem: 514156K av, 485724K used, 28432K free, 0K shrd, 57956K buff Swap: 522072K av, 44048K used, 478024K free 288448K cached PID USER PRI NI SIZE RSS SHARE STAT %CPU %MEM TIME COMMAND 18840 mersenne 39 19 14996 14M 696 R N 99.9 2.9 7046m mprime 14091 marco 15 0 1084 1084 848 R 0.1 0.2 0:00 top 1 root 15 0 472 444 420 S 0.0 0.0 0:04 init 2 root 15 0 0 0 0 SW 0.0 0.0 0:01 keventd 3 root 15 0 0 0 0 SW 0.0 0.0 0:00 kapmd As you can see the idle value is absurd (it blows up about 1 in five times, other updates are reasonable e.g. 0.2% idle). When running "top" the value consistently jumps to about 800000% about 20% of the time. If I run "top -d1" so that the updates take place every second the value consistently jumps to about 4200000%, again about 20% of the time. Running "top -d2" makes it jump to around 2000000%. The idle value behaves approximately as follows: 4200000 idle = --------% once every five updates. interval If I stop "mprime" so that the system load becomes negligible the idle value does not spike. If I run "mprime" or any other CPU-consuming task (e.g. yes > dev/null) the spikes commence. The niceness of the process does not seem to matter. My hardware is an Athlon 2100+ running on an ASUS A7V333. > uname -a Linux reimeika.math.toronto.edu 2.4.18-17.7.x #1 Tue Oct 8 11:49:30 EDT 2002 i686 unknown > top --version top (procps version 2.0.7) I should note that all previous Red Hat 7.3 kernels ran fine. It's telling that according to the 2.4.18-17.7.x errata at: http://rhn.redhat.com/errata/RHSA-2002-206.html it's mentioned that the following bug: /proc/uptime shows wrong uptime (slightly) and idle time (totally) ( http://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=75113 ) has been fixed. Kernel bug? "top" bug? Something else? Suggestions appreciated. Please CC responses to my "Reply-To:" if possible. Cheers, -- marco@reimeika.ca Gunnm: Broken Angel http://reimeika.ca/