Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755950AbZDFOG6 (ORCPT ); Mon, 6 Apr 2009 10:06:58 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753081AbZDFOGq (ORCPT ); Mon, 6 Apr 2009 10:06:46 -0400 Received: from caffeine.csclub.uwaterloo.ca ([129.97.134.17]:48413 "EHLO caffeine.csclub.uwaterloo.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755329AbZDFOGq (ORCPT ); Mon, 6 Apr 2009 10:06:46 -0400 Date: Mon, 6 Apr 2009 10:06:44 -0400 To: Jeff Garzik Cc: Janne Grunau , David Rees , Mark Lord , Jens Axboe , Linus Torvalds , Ingo Molnar , Andrew Morton , tytso@mit.edu, jesper@krogh.cc, Linux Kernel Mailing List Subject: Re: Linux 2.6.29 Message-ID: <20090406140643.GL3795@csclub.uwaterloo.ca> References: <20090403072507.GO5178@kernel.dk> <20090403142129.GH3795@csclub.uwaterloo.ca> <49D625A0.1030202@rtr.ca> <49D66A40.5020503@garzik.org> <20090403212847.GC25887@aniel> <49D68631.4030706@garzik.org> <72dbd3150904031553r3c60a3a5k45f16e0e7513d488@mail.gmail.com> <49D69C1D.50209@garzik.org> <20090404162954.GA5170@aniel> <49D7E71B.2080301@garzik.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <49D7E71B.2080301@garzik.org> User-Agent: Mutt/1.5.18 (2008-05-17) From: lsorense@csclub.uwaterloo.ca (Lennart Sorensen) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1097 Lines: 23 On Sat, Apr 04, 2009 at 07:02:51PM -0400, Jeff Garzik wrote: > Is dd + sync_file_range really a realistic comparison? dd is streaming > as fast as the disk can output data, whereas MythTV is streaming as fast > as video is being recorded. If you are maxing out your disk throughput, > there will be obvious impact no matter what. > > I would think a more accurate comparison would be recording multiple > video streams in parallel, comparing fsync/fdatasync/sync_file_range? > > IOW, what is an average MythTV setup -- what processes are actively > reading/writing storage? Where are you noticing latencies, and does > sync_file_range decrease those areas of high latency? I am going to give the patch a shot. I run dual tuners after all, so I do get multiple streams recording while doing playback at the same time. -- Len Sorensen -- 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/