From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753036AbbCaIcy (ORCPT ); Tue, 31 Mar 2015 04:32:54 -0400 Received: from mga02.intel.com ([134.134.136.20]:61855 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752203AbbCaIcu (ORCPT ); Tue, 31 Mar 2015 04:32:50 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.11,499,1422950400"; d="scan'208";a="673032880" Message-ID: <1427790767.17170.95.camel@intel.com> Subject: Re: [LKP] [Btrfs] 3a8b36f3780: -62.6% fileio.requests_per_sec From: Huang Ying To: Filipe Manana Cc: Chris Mason , LKML , LKP ML Date: Tue, 31 Mar 2015 16:32:47 +0800 In-Reply-To: <55094E06.2070004@suse.com> References: <1426666837.5570.36.camel@intel.com> <55094E06.2070004@suse.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.12.9-1+b1 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, Filipe, On Wed, 2015-03-18 at 10:05 +0000, Filipe Manana wrote: [snip] > Hi, thanks for this. > > However this doesn't make sense to me. > This commit only touches btrfs' fsync handler and the test uses sysbench > without passing --file-fsync-freq to it, which means sysbench will never > do fsyncs according to its man page (default for fsync frequency is 0). > > Or maybe I missed something? Sorry for late. I checked source code of sysbench and found that the actual default value of --file-fsync-freq is 100 instead of 0 in man page, as in the following lines. {"file-fsync-freq", "do fsync() after this number of requests (0 - don't use fsync())", SB_ARG_TYPE_INT, "100"}, I double checked that via a debug patch to sysbench too. Best Regards, Huang, Ying