From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757297AbYJVWv2 (ORCPT ); Wed, 22 Oct 2008 18:51:28 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753266AbYJVWvT (ORCPT ); Wed, 22 Oct 2008 18:51:19 -0400 Received: from mail-out2.uio.no ([129.240.10.58]:42790 "EHLO mail-out2.uio.no" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751529AbYJVWvS (ORCPT ); Wed, 22 Oct 2008 18:51:18 -0400 Subject: Re: SUNRPC problem with 2.6.26 and beyond From: Trond Myklebust To: Harry Edmon Cc: linux-kernel@vger.kernel.org In-Reply-To: <48FF482F.5060002@atmos.washington.edu> References: <48FF482F.5060002@atmos.washington.edu> Content-Type: text/plain Date: Wed, 22 Oct 2008 18:51:14 -0400 Message-Id: <1224715874.7525.18.camel@localhost> Mime-Version: 1.0 X-Mailer: Evolution 2.22.3.1 Content-Transfer-Encoding: 7bit X-UiO-Spam-info: not spam, SpamAssassin (score=0.0, required=5.0, autolearn=disabled, MISSING_SUBJECT=0.001,NO_RECEIVED=-0.001, uiobl=NO, uiouri=NO) X-UiO-Scanned: B265BA851D165AFA28F89D53ACECFB9AA9558DA5 X-UiO-SPAM-Test: remote_host: 68.40.183.129 spam_score: 0 maxlevel 200 minaction 2 bait 0 mail/h: 5 total 123 max/h 9 blacklist 0 greylist 0 ratelimit 0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2008-10-22 at 08:35 -0700, Harry Edmon wrote: > I have a dual quad-core Xeon system running software > (http://www.unidata.ucar.edu/software/ldm) that relays and processes > weather data through RPC calls, keeping a queue of data in a memory > mapped file. Up until 2.6.26 the system has run just fine (for example > 2.6.25.17). But starting with 2.6.26 through 2.6.27.2 the system runs > into a problem after approximately 24 hours. The symptom is that the > processing slows down to a crawl. Using "top" I can see that the System > time is up over 90%, with almost no User and Wait time. If I stop and > restart the software, most of the time it gets better - but sometimes it > takes a reboot to fix the problem. I have an identical system that does > just processing and ingesting data from remote systems, and it does not > have this problem. I have tried a number of different kernel > configurations, but they all show the same problem. > > I suspect a problem with SUNRPC. I notice that there were a large > number of SUNRPC patches in 2.6.26. I am looking for suggestions on how > to pin down which patches are causing the problem. Are there ways to > figure where in the kernel the time is being spent? I am will to work > on isolating the problem, but I need some suggestions on the best way to > do it given the large number of SUNRPC patches in 2.6.26 and the fact > that each experiment takes a day. The kernel sunrpc interface is not exported to user land: the glibc code uses its own, entirely separate implementation of sunrpc. I cannot therefore see, how your application's RPC calls can be affected by kernel sunrpc changes. Cheers Trond