From: Theodore Tso Subject: Re: [PATCH] Add ext3 data=guarded mode Date: Fri, 17 Apr 2009 16:13:42 -0400 Message-ID: <20090417201342.GF26479@mit.edu> References: <1239816159-6868-1-git-send-email-chris.mason@oracle.com> <1239910921.21233.98.camel@think.oraclecorp.com> <20090417180906.GA8363@amit-x200.pnq.redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Chris Mason , Jan Kara , Linus Torvalds , Linux Kernel Developers List , Ext4 Developers List To: Amit Shah Return-path: Received: from THUNK.ORG ([69.25.196.29]:60769 "EHLO thunker.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751880AbZDQUOE (ORCPT ); Fri, 17 Apr 2009 16:14:04 -0400 Content-Disposition: inline In-Reply-To: <20090417180906.GA8363@amit-x200.pnq.redhat.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Fri, Apr 17, 2009 at 11:39:06PM +0530, Amit Shah wrote: > # 4GiB file, kernel 9f76208c33984ab777eace5d07a4e36e88703e02 + ext3-guarded > > filesystem posix-fallocate mmap chunk-4096 chunk-8192 > ext3-guarded 85 97 459 90 > ext3-writeback 86 95 140 94 > ext3-ordered 86 96 277 95 > > Running the test in single user mode, I get the following results: > > # 4GiB file, kernel 9f76208c33984ab777eace5d07a4e36e88703e02 + ext3-guarded > > filesystem posix-fallocate mmap chunk-4096 chunk-8192 > ext3-guarded 84 86 163 91 > ext3-writeback 84 88 217 91 > ext3-ordered 84 86 226 91 The difference between guarded and writeback in chunk-4096 looking at your desktop timings and your single user times is.... surprising. In particular, the fact that the guarded time is 3 times longer than ext3-writeback when the desktop is running, and 20% faster in single user mode. Are these results reproducible? And do you have any thoughts as to what might be causing them? - Ted