From: Trond Myklebust Subject: Re: Fwd: 2.6.26.3 kernel - progressive slowdown over NFS Date: Tue, 09 Dec 2008 20:06:45 -0500 Message-ID: <1228871206.30231.76.camel@heimdal.trondhjem.org> References: <2c0942db0812091638o3d0fe68ek70744f6938949b25@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain Cc: LKML , linux-nfs@vger.kernel.org, Netdev To: Ray Lee Return-path: Received: from mail-out1.uio.no ([129.240.10.57]:58357 "EHLO mail-out1.uio.no" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752243AbYLJBGv (ORCPT ); Tue, 9 Dec 2008 20:06:51 -0500 In-Reply-To: <2c0942db0812091638o3d0fe68ek70744f6938949b25-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org> Sender: linux-nfs-owner@vger.kernel.org List-ID: On Tue, 2008-12-09 at 16:38 -0800, Ray Lee wrote: > [ adding netdev, linux-nfs to cc: -- rbl ] > > Hi, > > > We have a simple python program which keeps running a C loop to lstat > NFS mounted directories. We are seeing some weird behavior w.r.t. the > run-time of this program on 2.6.26.3 kernel vs 2.6.24 kernel. > > The run-time of the following code increases over time on the 2.6.26.3 > kernel, whereas remains flat (as expected) on the 2.6.24 kernel. > [See attached graphs - B1.jpg and B2.jpg] Once the 2.6.26.3 machine > gets into this state, we need to restart the box to get back to > reasonable run-times. Is this a known issue ? Could you try applying the following patch? http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git&a=commitdiff&h=23918b03060f6e572168fdde1798a905679d2e06 Trond PS: note that your 2.6.26 config file has _very_ different memory models and kernel debugging options enabled compared to your 2.6.24 kernel. That may also affect performance.