Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752621Ab2JJJCk (ORCPT ); Wed, 10 Oct 2012 05:02:40 -0400 Received: from li9-11.members.linode.com ([67.18.176.11]:54782 "EHLO imap.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751395Ab2JJJCh (ORCPT ); Wed, 10 Oct 2012 05:02:37 -0400 Date: Wed, 10 Oct 2012 05:02:28 -0400 From: "Theodore Ts'o" To: Jooyoung Hwang Cc: "'Vyacheslav Dubeyko'" , "'Marco Stornelli'" , "'Jaegeuk Kim'" , "'Al Viro'" , gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, chur.lee@samsung.com, cm224.lee@samsung.com, linux-fsdevel@vger.kernel.org Subject: Re: [PATCH 00/16] f2fs: introduce flash-friendly file system Message-ID: <20121010090228.GD11481@thunk.org> Mail-Followup-To: Theodore Ts'o , Jooyoung Hwang , 'Vyacheslav Dubeyko' , 'Marco Stornelli' , 'Jaegeuk Kim' , 'Al Viro' , gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, chur.lee@samsung.com, cm224.lee@samsung.com, linux-fsdevel@vger.kernel.org References: <415E76CC-A53D-4643-88AB-3D7D7DC56F98@dubeyko.com> <9DE65D03-D4EA-4B32-9C1D-1516EAE50E23@dubeyko.com> <1349553966.12699.132.camel@kjgkr> <50712AAA.5030807@gmail.com> <002201cda46e$88b84d30$9a28e790$%kim@samsung.com> <004101cda52e$72210e20$56632a60$%kim@samsung.com> <55A93BD0-CBCB-4707-A970-EB823EC54B2D@dubeyko.com> <006f01cda5ec$e63e9b60$b2bbd220$%kim@samsung.com> <1349812406.18456.41.camel@adg-desktop-09.cs.wisc.edu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1349812406.18456.41.camel@adg-desktop-09.cs.wisc.edu> User-Agent: Mutt/1.5.21 (2010-09-15) X-SA-Exim-Connect-IP: X-SA-Exim-Mail-From: tytso@thunk.org X-SA-Exim-Scanned: No (on imap.thunk.org); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1416 Lines: 29 On Tue, Oct 09, 2012 at 02:53:26PM -0500, Jooyoung Hwang wrote: > I'd like you to refer to the following link as well which is about > mobile workload pattern. > http://www.cs.cmu.edu/~fuyaoz/courses/15712/report.pdf > It's reported that in Android there are frequent issues of fsync and > most of them are only for small size of data. What bothers me is no one is asking the question, *why* is Android (and more specifically SQLite and the applications which call SQLite) using fsync's so often? These aren't transaction processing systems, after all. So there are two questions that are worth asking here. (a) Is SQLite being as flash-friendly as possible, and (b) do the applications really need as many transaction boundaries as they are requesting of SQLite. Yes, we can optimize the file system, but sometimes the best way to optimize a write is to not to do the write at all (if it is not required for the application's functionality, of course). If the application is requesting 4 transaction boundaries where only one is required, we can try to make fsync's more efficient, yes --- but there is only so much that can be done at the fs layer. - Ted -- 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/