From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx3.redhat.com (mx3.redhat.com [172.16.48.32]) by int-mx1.corp.redhat.com (8.11.6/8.11.6) with ESMTP id j4QBoXO25563 for ; Thu, 26 May 2005 07:50:33 -0400 Received: from palrel10.hp.com (palrel10.hp.com [156.153.255.245]) by mx3.redhat.com (8.12.11/8.12.11) with ESMTP id j4QBoRtM027405 for ; Thu, 26 May 2005 07:50:27 -0400 Received: from power.usa.hp.com (amps.usa.hp.com [16.119.180.11]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by palrel10.hp.com (Postfix) with ESMTP id 9D404106E for ; Thu, 26 May 2005 04:50:21 -0700 (PDT) Received: from [127.0.0.1] ([15.228.168.250]) by power.usa.hp.com (8.12.11/) with ESMTP id j4QBoGr7691555 for ; Thu, 26 May 2005 07:50:19 -0400 (EDT) Message-ID: <4295B7F7.9060802@hp.com> Date: Thu, 26 May 2005 07:50:15 -0400 From: Howard Rifkin MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: [linux-lvm] Daemon or Thread with 5 minute interval Reply-To: howard.rifkin@hp.com, LVM general discussion and development List-Id: LVM general discussion and development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , List-Id: Content-Type: text/plain; charset="us-ascii"; format="flowed" To: linux-lvm@redhat.com I have been working on a project that analyzes "noise" in Linux clusters running large parallel jobs. Where noise is caused by daemons or kernel threads periodically waking up and slowing down a process of a parallel job enough so that is misses a rendezvous with the other processes and so slows down the entire job. Using an internal tool I have been able to track down several daemons that have been a large source of noise but, after turning them all off I am left with a large noise spike that occurs every 5 minutes. I have tried turning off most of the most common daemons such as cron, ntp, syslog, ect. but, I am still left with this spike. Not being a kernel expert myself I have not been able to experiment with kernel threads. So, my question is does anyone know of a kernel thread or daemon in the 2.4 kernel that wakes up every 5 minutes? Thanks Howard