Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752932AbaGHG2Q (ORCPT ); Tue, 8 Jul 2014 02:28:16 -0400 Received: from odin2.bull.net ([129.184.85.11]:48158 "EHLO odin2.bull.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751931AbaGHG2O (ORCPT ); Tue, 8 Jul 2014 02:28:14 -0400 Message-ID: <53BB8F7C.1060505@bull.net> Date: Tue, 8 Jul 2014 08:28:12 +0200 From: Sebastien Buisson User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.9; rv:24.0) Gecko/20100101 Thunderbird/24.6.0 MIME-Version: 1.0 To: Andi Kleen , Andrew Morton CC: , , Subject: Re: [PATCH] Allow increasing the buffer-head per-CPU LRU size References: <53B667F9.90306@bull.net> <87y4w6sbp7.fsf@tassilo.jf.intel.com> <53BA772C.6040506@bull.net> <20140707163003.GA18735@two.firstfloor.org> <20140707152936.a286b0f46ae1b06aa41c1959@linux-foundation.org> <20140707224634.GE18735@two.firstfloor.org> In-Reply-To: <20140707224634.GE18735@two.firstfloor.org> Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [10.192.1.123] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org >> Can anyone demonstrate why we shouldn't just do > > I was assuming due to memory usage: with 4K blocks 32K->64K > Moreover, performance gain was not that satisfactory on ext4 when increasing BH_LRU_SIZE to 16. Here are the performances I got with: (a) mdtest on ramdisk device, single shared dir, with large ACL and SELinux (b) mdtest on ramdisk device, single shared dir, with large ACL but NO SELinux (results show performance gain in percentage when increasing BH_LRU_SIZE to 16) (a) files tasks dir size Creation Stat Removal 1000000 1 0 -8,7 -2,7 -0,5 1000000 1 100000 -5,2 -0,5 -1,1 1000000 1 500000 -5,1 -3,7 -1,5 1000000 1 2000000 -5,1 -4,0 -8,5 1000000 1 5000000 -4,2 -5,3 -10,2 1000000 1 10000000 -3,5 -8,0 -10,9 1000000 8 0 -0,3 -3,8 -1,2 1000000 8 100000 -1,2 -3,7 -1,5 1000000 8 500000 0,5 -3,2 -5,3 1000000 8 2000000 -1,7 -6,1 -8,7 1000000 8 5000000 -5,9 -7,7 -11,9 1000000 8 10000000 -4,1 -8,8 -13,6 (b) files tasks dir size Creation Stat Removal 1000000 1 0 0,0 -0,9 -1,1 1000000 1 100000 1,0 -3,0 -3,5 1000000 1 500000 3,7 -3,0 -2,4 1000000 1 2000000 1,1 3,6 -0,2 1000000 1 5000000 3,5 0,1 5,9 1000000 1 10000000 9,0 3,8 6,4 1000000 8 0 2,4 -1,2 -4,3 1000000 8 100000 -0,2 -1,8 -2,4 1000000 8 500000 1,1 -0,3 2,0 1000000 8 2000000 -0,3 -2,8 -3,3 1000000 8 5000000 0,3 -3,1 -1,3 1000000 8 10000000 1,5 0,0 0,7 To compare with the performances I got on Lustre with: (c) mds-survey on ramdisk device, quota enabled, shared directory (d) mds-survey on ramdisk device, quota enabled, directory per process (c) fi dir threads create lookup destroy 1000000 1 1 11,3 1,2 7,2 1000000 1 2 6,4 2,3 6,9 1000000 1 4 1,9 3,0 1,3 1000000 1 8 -0,6 4,3 0,7 1000000 1 16 0,5 4,4 0,6 (d) files dir threads create lookup destroy 1000000 4 4 3,2 28,5 5,3 1000000 8 8 1,2 33,9 2,0 1000000 16 16 0,6 7,9 -0,2 Sebastien. -- 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/