Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752734AbXL0Ly7 (ORCPT ); Thu, 27 Dec 2007 06:54:59 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751598AbXL0Lyw (ORCPT ); Thu, 27 Dec 2007 06:54:52 -0500 Received: from srv5.dvmed.net ([207.36.208.214]:44102 "EHLO mail.dvmed.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751533AbXL0Lyv (ORCPT ); Thu, 27 Dec 2007 06:54:51 -0500 Message-ID: <47739288.7000308@garzik.org> Date: Thu, 27 Dec 2007 06:54:48 -0500 From: Jeff Garzik User-Agent: Thunderbird 2.0.0.9 (X11/20071115) MIME-Version: 1.0 To: saeed bishara CC: linux-kernel@vger.kernel.org, NFS list Subject: Re: read-ahead in NFS server References: <47730F2F.3080900@garzik.org> In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Score: -4.4 (----) X-Spam-Report: SpamAssassin version 3.2.3 on srv5.dvmed.net summary: Content analysis details: (-4.4 points, 5.0 required) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1250 Lines: 35 saeed bishara wrote: >> (linux-nfs added to cc) >> >> I cannot speak for the NFS server code specifically, but 32kb sounds >> like a network read (or write) data size limit. > yes >> Are you using TCP? Are you using NFSv4, or an older version? > I'm using NFSv3/UDP. IMO, you definitely want TCP and NFSv4. Much better network behavior, with some of the silly UDP limits (plus greatly improved caching behavior, due to v4 delegations). > I found that the actual requests size was 16KB, after doing some hacks > in server&client I managed to make it 60KB, now I see better > performance, and I see that the average request size is ~130KB which > means that there is actually read-ahead. but why it's only 130KB? how > can I make it larger? > when I run local dd with bs=4K, I can see that the average IO size is > more than 300KB. Read-ahead is easier in NFSv4, because the client probably has the file delegated locally, and has far less need to constantly revalidate file mapping(s). Jeff -- 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/