From: Frank van Maarseveen Subject: Re: [PATCH 4/5] NFSD: Remove NFSD_TCP kernel build option Date: Tue, 5 Feb 2008 16:50:22 +0100 Message-ID: <20080205155021.GA7805@janus> References: <20080205000442.18602.29035.stgit@manray.1015granger.net> <47A7AB89.7020709@melbourne.sgi.com> <1202170754.28484.57.camel@heimdal.trondhjem.org> <47A7AE03.10401@melbourne.sgi.com> <4BE5A1AE-DB3B-4796-B6BD-5691930258C8@oracle.com> <47A7F8F3.3020907@melbourne.sgi.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Chuck Lever , Trond Myklebust , bfields@citi.umich.edu, linux-nfs@vger.kernel.org To: Greg Banks Return-path: Received: from frankvm.xs4all.nl ([80.126.170.174]:35484 "EHLO janus.localdomain" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1756049AbYBEPuX (ORCPT ); Tue, 5 Feb 2008 10:50:23 -0500 In-Reply-To: <47A7F8F3.3020907-cP1dWloDopni96+mSzHFpQC/G2K4zDHf@public.gmane.org> Sender: linux-nfs-owner@vger.kernel.org List-ID: On Tue, Feb 05, 2008 at 04:49:39PM +1100, Greg Banks wrote: > Chuck Lever wrote: > > On Feb 4, 2008, at 7:29 PM, Greg Banks wrote: > >> Trond Myklebust wrote: > >>> On Tue, 2008-02-05 at 11:19 +1100, Greg Banks wrote: > >>> > >>>> Chuck Lever wrote: > >>>> > >>>>> TCP support in the Linux NFS server is stable enough that we can > >>>>> leave it > >>>>> on always. CONFIG_NFSD_TCP adds about 10 lines of code, and > >>>>> defaults to > >>>>> "Y" anyway. > >>>>> > >>>>> A run-time switch might be more appropriate if people feel they > >>>>> would like > >>>>> to disable NFSD's TCP support. > >>>>> > >>>>> > >>>>> > >>>> Looks good. > >>>> > >>>> Actually, I'd be inclined to go one step further and set UDP support > >>>> off by default. > >>>> > >>> > >>> That will break older clients. > >>> > >>> > >> Hence the default, rather than removing the code entirely. > > > > > > What might make sense is to remove NFSD_TCP, but add NFSD_UDP, > > defaulting to Y. > > > > Then in a year or two we can change the default to N. > > > Fine by me. Last time I checked (around 2.6.22) writing large files on NFSv3 over UDP was 20% faster compared to TCP (Gb LAN with one switch connecting all machines). TCP and its timeout/retransmission behavior isn't always the best choice. -- Frank