From owner-svn-src-head@FreeBSD.ORG Mon Aug 9 22:56:11 2010 Return-Path: Delivered-To: svn-src-head@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 2334C106564A; Mon, 9 Aug 2010 22:56:11 +0000 (UTC) (envelope-from ivoras@FreeBSD.org) Received: from svn.freebsd.org (svn.freebsd.org [IPv6:2001:4f8:fff6::2c]) by mx1.freebsd.org (Postfix) with ESMTP id 127348FC17; Mon, 9 Aug 2010 22:56:11 +0000 (UTC) Received: from svn.freebsd.org (localhost [127.0.0.1]) by svn.freebsd.org (8.14.3/8.14.3) with ESMTP id o79MuAT3031490; Mon, 9 Aug 2010 22:56:10 GMT (envelope-from ivoras@svn.freebsd.org) Received: (from ivoras@localhost) by svn.freebsd.org (8.14.3/8.14.3/Submit) id o79MuAnm031488; Mon, 9 Aug 2010 22:56:10 GMT (envelope-from ivoras@svn.freebsd.org) Message-Id: <201008092256.o79MuAnm031488@svn.freebsd.org> From: Ivan Voras Date: Mon, 9 Aug 2010 22:56:10 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org X-SVN-Group: head MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Cc: Subject: svn commit: r211126 - head/sys/kern X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 09 Aug 2010 22:56:11 -0000 Author: ivoras Date: Mon Aug 9 22:56:10 2010 New Revision: 211126 URL: http://svn.freebsd.org/changeset/base/211126 Log: Bumping the read-ahead count once more, to value equivalent to 512 KiB on most system, based on benchmark results on a low-end fibre channel SAN under VMWare: vfs.read_max read performance 8 (historical default) 83 MB/s 16 (recent bump) 131 MB/s 32 (this version) 152 MB/s 64 157 MB/s (results are +/- 3 MB/s) As read-ahead is heuristic, based on past IO requests, it shouldn't be problematic. The new default is still smaller then in other OSes. Modified: head/sys/kern/vfs_cluster.c Modified: head/sys/kern/vfs_cluster.c ============================================================================== --- head/sys/kern/vfs_cluster.c Mon Aug 9 22:30:14 2010 (r211125) +++ head/sys/kern/vfs_cluster.c Mon Aug 9 22:56:10 2010 (r211126) @@ -71,7 +71,7 @@ static int write_behind = 1; SYSCTL_INT(_vfs, OID_AUTO, write_behind, CTLFLAG_RW, &write_behind, 0, "Cluster write-behind; 0: disable, 1: enable, 2: backed off"); -static int read_max = 16; +static int read_max = 32; SYSCTL_INT(_vfs, OID_AUTO, read_max, CTLFLAG_RW, &read_max, 0, "Cluster read-ahead max block count");