From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Sat, 27 Jan 2001 03:01:48 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Sat, 27 Jan 2001 03:01:38 -0500 Received: from horus.its.uow.edu.au ([130.130.68.25]:56988 "EHLO horus.its.uow.edu.au") by vger.kernel.org with ESMTP id ; Sat, 27 Jan 2001 03:01:26 -0500 Message-ID: <3A72820A.1488BDC@uow.edu.au> Date: Sat, 27 Jan 2001 19:08:42 +1100 From: Andrew Morton X-Mailer: Mozilla 4.7 [en] (X11; I; Linux 2.4.0-test8 i586) X-Accept-Language: en MIME-Version: 1.0 To: Shawn Starr CC: Chris Mason , Gregory Maxwell , linux-kernel@vger.kernel.org Subject: Re: Kernel 2.4.x and 2.4.1-preX - Higher latency then 2.2.xkernels? In-Reply-To: <186870000.980100593@tiny> <3A6B6FDE.93AF69CC@Home.net> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Shawn, I've pretty much completed the low-latency patch against reiserfs. It seems to be a little more latency-prone than ext2, but under normal workloads it's not significant. The worst-case is 100 milliseconds, but that's when you're doing insane things to it. You may care to apply http://www.uow.edu.au/~andrewm/linux/2.4.1-pre10-low-latency.patch against 2.4.1-pre10 and see if it "feels" different. I'd be surprised if it does, but the result would be interresting. Note that the low-latency capability must be enabled under the "Processor type and features" menu, and if you also enable the low-latency sysctl option, you'll need to echo 1 > /proc/sys/kernel/lowlatency to make it happen. Creature feep :) Shawn Starr wrote: > > Sure, but Im not sure what to test ;) > If you've got any special patches for 2.4 lemme know and I'll apply them I've > got all night heh > > Shawn. > > Chris Mason wrote: > > > On Saturday, January 20, 2001 02:59:24 PM -0500 Gregory Maxwell > > wrote: > > > > > On Sat, Jan 20, 2001 at 02:50:16PM -0500, Shawn Starr wrote: > > >> It just seems that since using 2.4 ive noticed my poor Pentium 200Mhz > > >> slow down whether being in X or otherwise. It just seems that the system > > >> is sluggish. > > >> > > >> I am using the new ReiserFS filesystem and I do know its still in heavy > > >> development perhaps my latency is due to this (?) > > > > > > Reiserfs uses much more complex data structures then ext2 (trees..). I > > > don't think that latency has ever been a design criteria and all of the > > > benchmarks they use are pretty much pure throughput tests. > > > > > > So it wouldn't be really surprising if reiserfs had very bad latency. You > > > should apply the timepegs patch and profile your kernel latency to see > > > where it's coming from. > > > > I'm actually very interested in fixing any latency problems. If you do > > these tests, please send the results along. > > > > -chris > > - > > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > > the body of a message to majordomo@vger.kernel.org > > Please read the FAQ at http://www.tux.org/lkml/ > > - > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > Please read the FAQ at http://www.tux.org/lkml/ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org Please read the FAQ at http://www.tux.org/lkml/