Return-Path: Received: from int-mailstore01.merit.edu ([207.75.116.232]:41125 "EHLO int-mailstore01.merit.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750874Ab1FHCSy (ORCPT ); Tue, 7 Jun 2011 22:18:54 -0400 Date: Tue, 7 Jun 2011 22:18:52 -0400 From: Jim Rees To: Benny Halevy Cc: linux-nfs@vger.kernel.org, peter honeyman Subject: Re: [PATCH 87/88] Add configurable prefetch size for layoutget Message-ID: <20110608021852.GA20998@merit.edu> References: <09142112ff0115f7f22124a69ead7b9bb5e0958f.1307464382.git.rees@umich.edu> <4DEED80A.4000102@panasas.com> Content-Type: text/plain; charset=us-ascii In-Reply-To: <4DEED80A.4000102@panasas.com> Sender: linux-nfs-owner@vger.kernel.org List-ID: MIME-Version: 1.0 Benny Halevy wrote: NAK. This affects all layout types. In particular it is undesired for write layouts that extend the file with the objects layout. The server can extend the layout segments range over what the client requested so why would the client ask for artificially large layouts? This has actually been the subject of some debate over Thursday night beers. The problem we're trying to solve is that the client is spending 98% of its time in layoutget. This patch gives us something like a 10x speedup. But many of us think it's not the right fix. I suggest we discuss next week. But note that this patch doesn't change anything unless you set the sysctl.