From mboxrd@z Thu Jan 1 00:00:00 1970 From: Greg Banks Subject: [PATCH] SGI 905314 (2/2): document constraints on client transfer size Date: Fri, 28 Nov 2003 23:45:52 +1100 Sender: nfs-admin@lists.sourceforge.net Message-ID: <3FC74380.6367DBAA@melbourne.sgi.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Linux NFS Mailing List Return-path: Received: from sc8-sf-mx2-b.sourceforge.net ([10.3.1.12] helo=sc8-sf-mx2.sourceforge.net) by sc8-sf-list1.sourceforge.net with esmtp (Cipher TLSv1:DES-CBC3-SHA:168) (Exim 3.31-VA-mm2 #1 (Debian)) id 1APi0p-0001XT-00 for ; Fri, 28 Nov 2003 04:46:19 -0800 Received: from mtvcafw.sgi.com ([192.48.171.6] helo=zok.sgi.com) by sc8-sf-mx2.sourceforge.net with esmtp (Exim 4.24) id 1APi0p-0005ZF-In for nfs@lists.sourceforge.net; Fri, 28 Nov 2003 04:46:19 -0800 To: Trond Myklebust Errors-To: nfs-admin@lists.sourceforge.net List-Help: List-Post: List-Subscribe: , List-Id: Discussion of NFS under Linux development, interoperability, and testing. List-Unsubscribe: , List-Archive: G'day, SGI bug #905314 This patch adds a comment documenting the actual constraints on NFS_MAX_FILE_IO_BUFFER_SIZE for the next guy who needs to know ;-) --- /usr/tmp/TmpDir.28396-0/linux/linux/include/linux/nfs_fs.h_1.21 Fri Nov 28 23:07:47 2003 +++ linux/include/linux/nfs_fs.h Fri Nov 28 21:55:30 2003 @@ -40,6 +40,18 @@ */ #define NFS_MAX_DIRCACHE 16 +/* + * NFS_MAX_FILE_IO_BUFFER_SIZE limits the rsize and wsize that + * userspace can request in mount options (note that the server + * also gives us a limit in response to the FSINFO call). The + * value is constrained by 1) has to fit in a UDP datagram less + * some headers 2) has to be a multiple of page size 3) has to + * be no more than NFS_READ_MAXIOV=8 pages for rsize, and + * NFS_WRITE_MAXIOV=8 pages for wsize and 4) has to be a power + * of two (actually this is bogus but nfs_read_super relies on it). + * For best performance we usually want the largest value + * consistent with these constraints. + */ #define NFS_MAX_FILE_IO_BUFFER_SIZE 32768 #define NFS_DEF_FILE_IO_BUFFER_SIZE 4096 Greg. -- Greg Banks, R&D Software Engineer, SGI Australian Software Group. I don't speak for SGI. ------------------------------------------------------- This SF.net email is sponsored by: SF.net Giveback Program. Does SourceForge.net help you be more productive? Does it help you create better code? SHARE THE LOVE, and help us help YOU! Click Here: http://sourceforge.net/donate/ _______________________________________________ NFS maillist - NFS@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/nfs