Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264795AbUD1Nr6 (ORCPT ); Wed, 28 Apr 2004 09:47:58 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264793AbUD1Nr6 (ORCPT ); Wed, 28 Apr 2004 09:47:58 -0400 Received: from smtp807.mail.sc5.yahoo.com ([66.163.168.186]:7835 "HELO smtp807.mail.sc5.yahoo.com") by vger.kernel.org with SMTP id S264795AbUD1NrQ (ORCPT ); Wed, 28 Apr 2004 09:47:16 -0400 Date: Wed, 28 Apr 2004 08:50:40 -0500 (CDT) From: Brent Cook X-X-Sender: busterb@ozma.hauschen Reply-To: busterbcook@yahoo.com To: Andrew Morton cc: linux-kernel@vger.kernel.org Subject: Re: pdflush eating a lot of CPU on heavy NFS I/O In-Reply-To: <20040427230203.1e4693ac.akpm@osdl.org> Message-ID: References: <20040427230203.1e4693ac.akpm@osdl.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2558 Lines: 65 On Tue, 27 Apr 2004, Andrew Morton wrote: > Brent Cook wrote: > > > > Running any kernel from the 2.6.6-rc* series (and a few previous > > -mm*'s), > > It's a shame this wasn't reported earlier. Since it was a pretty big deal on my system, I just assumed it was for other people's too, and that someone else would have reported it by now. I only got concerned when it persisted between rc's. > > the pdflush process starts using near 100% CPU indefinitely after > > a few minutes of initial NFS traffic, as far as I can tell. > > Please confirm that the problem is observed on the NFS client and not the > NFS server? I'll assume the client. Yes, both affected machines had the issue when connecting as a client to a 2.4.25-based NFS server. > What other filesystems are in use on the client? One uses Reiser on /, the other uses ext3 on /. Here is the mount table for one machine: /dev/hda3 on / type ext3 (rw) none on /dev/pts type devpts (rw,gid=5,mode=620) none on /proc type proc (rw) none on /sys type sysfs (rw) usbfs on /proc/bus/usb type usbfs (rw) ozma:/home on /home type nfs (rw,addr=192.168.1.1) Running 2.6.6-rc2-mm1, Here is a shot compiling KDE with the source on the NFS mount, -j2. This is the initial state: PID USER PRI NI SIZE RSS SHARE STAT %CPU %MEM TIME CPU COMMAND 12091 busterb 25 0 63524 59M 5140 R 38.4 23.8 0:19 0 cc1plus 12199 busterb 25 0 55660 52M 5140 R 38.0 20.8 0:07 0 cc1plus 7 root 16 0 0 0 0 SW 4.9 0.0 0:03 0 pdflush About 10 minutes into the process, pdflush starts taking over: PID USER PRI NI SIZE RSS SHARE STAT %CPU %MEM TIME CPU COMMAND 7 root 25 0 0 0 0 RW 34.4 0.0 3:05 0 pdflush 17856 busterb 25 0 69400 65M 5140 R 34.4 26.1 0:31 0 cc1plus 19466 busterb 25 0 43732 39M 5140 R 26.3 15.5 0:03 0 cc1plus After stopping the compile, pdflush remains until a reboot: PID USER PRI NI SIZE RSS SHARE STAT %CPU %MEM TIME CPU COMMAND 7 root 25 0 0 0 0 RW 98.0 0.0 3:21 0 pdflush The network light will flash continually on each machine once pdflush gets into this state, which makes me think NFS. Each machine has 512-256 MB of ram and a single CPU. - Brent - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/