From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751345AbWGKXLW (ORCPT ); Tue, 11 Jul 2006 19:11:22 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751347AbWGKXLV (ORCPT ); Tue, 11 Jul 2006 19:11:21 -0400 Received: from rwcrmhc11.comcast.net ([204.127.192.81]:51082 "EHLO rwcrmhc11.comcast.net") by vger.kernel.org with ESMTP id S1751345AbWGKXLV (ORCPT ); Tue, 11 Jul 2006 19:11:21 -0400 Message-ID: <44B43019.9010402@namesys.com> Date: Tue, 11 Jul 2006 16:11:21 -0700 From: Hans Reiser User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.5) Gecko/20041217 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Clay Barnes CC: Reiserfs mail-list , LKML , Alexander Lyamin aka FLX Subject: Re: short term task list for Reiser4 References: <44B42064.4070802@namesys.com> <20060711222903.GG9220@HAL_5000D.tc.ph.cox.net> In-Reply-To: <20060711222903.GG9220@HAL_5000D.tc.ph.cox.net> X-Enigmail-Version: 0.90.1.0 X-Enigmail-Supports: pgp-inline, pgp-mime 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 Clay Barnes wrote: >On 15:04 Tue 11 Jul , Hans Reiser wrote: > > >> >>6) optimize fsync --- substantive task which requires using fixed area >>for write twice logging, and using write twice logging for fsync'd >>data. It might require creating mount options to choose whether to >>optimize for serialized sequential fsyncs vs. lazy fsyncs. >> >> >With the serialized sequential fsync, is that essentially what I was >talking about earlier with slowly streaming dirty writes to disk when >the HDD is idle? If that's the case, I don't see the advantage in having >lazy fsyncs > if you are optimizing throughput rather than latency, then you let things get to disk whenever they get there, and you let the app hang while it waits. A mailer processing many requests in parallel might find 30 seconds of latency to be just fine but a database might find 3 seconds of latency to be too much. (I make up these examples, mailer programmers please correct me.) > except in situations where you want to keep the HDD spun down >as much as possible. > No, that is not when you do it. >I've been meaning to hose my laptop (assuming I fix one problem with my >desktop), so I am willing to help write Gentoo install docs (or possibly >Arch Linux). I can also test exsiting instructions. > > That would be way cool.