From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 26861 invoked by alias); 26 Jan 2006 16:58:48 -0000 Received: (qmail 26852 invoked by uid 22791); 26 Jan 2006 16:58:47 -0000 X-Spam-Status: No, hits=-2.5 required=5.0 tests=AWL,BAYES_00,SPF_HELO_PASS,SPF_PASS X-Spam-Check-By: sourceware.org Received: from mx1.redhat.com (HELO mx1.redhat.com) (66.187.233.31) by sourceware.org (qpsmtpd/0.31) with ESMTP; Thu, 26 Jan 2006 16:58:45 +0000 Received: from int-mx1.corp.redhat.com (int-mx1.corp.redhat.com [172.16.52.254]) by mx1.redhat.com (8.12.11/8.12.11) with ESMTP id k0QGwg9B025314 for ; Thu, 26 Jan 2006 11:58:42 -0500 Received: from pobox.corp.redhat.com (pobox.corp.redhat.com [172.16.52.156]) by int-mx1.corp.redhat.com (8.11.6/8.11.6) with ESMTP id k0QGwb123855; Thu, 26 Jan 2006 11:58:37 -0500 Received: from [172.16.59.162] (dhcp59-162.rdu.redhat.com [172.16.59.162]) by pobox.corp.redhat.com (8.12.8/8.12.8) with ESMTP id k0QGwbII016446; Thu, 26 Jan 2006 11:58:37 -0500 Message-ID: <43D8FFBD.5070900@redhat.com> Date: Thu, 26 Jan 2006 16:58:00 -0000 From: William Cohen User-Agent: Mozilla Thunderbird 1.0.7-1.1.fc4 (X11/20050929) X-Accept-Language: en-us, en MIME-Version: 1.0 To: Hien Nguyen CC: SystemTAP Subject: Re: LKML watch References: <43CFF71D.4090502@us.ibm.com> In-Reply-To: <43CFF71D.4090502@us.ibm.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-IsSubscribed: yes Mailing-List: contact systemtap-help@sourceware.org; run by ezmlm Precedence: bulk List-Subscribe: List-Post: List-Help: , Sender: systemtap-owner@sourceware.org X-SW-Source: 2006-q1/txt/msg00287.txt.bz2 Looking over LKML Found the two threads that have stuff of interest to SystemTap work. sendfile() with 100 simultaneous 100MB files http://www.ussg.iu.edu/hypermail/linux/kernel/0601.2/2077.html Performance problems when sending many large files. Not clear what the root cause is. Currently, workaround in userspace. Ben LaHaise had a hypthesis that it was requests overrun in the disk elevator: http://www.ussg.iu.edu/hypermail/linux/kernel/0601.2/2378.html There is a bugzilla entry for this problem: http://bugzilla.kernel.org/show_bug.cgi?id=5949 --- RCU latency regression in 2.6.16-rc1 http://www.ussg.iu.edu/hypermail/linux/kernel/0601.3/0022.html Port of latency tracer used to show latency problem. This is the type of problem that people would be interested in using SystemTap for. The latency tracer patches: http://people.redhat.com/mingo/latency-tracing-patches/ -Will