From owner-freebsd-net@FreeBSD.ORG Thu Jan 25 01:18:42 2007 Return-Path: X-Original-To: freebsd-net@freebsd.org Delivered-To: freebsd-net@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 88C3216A404 for ; Thu, 25 Jan 2007 01:18:42 +0000 (UTC) (envelope-from kbyanc@posi.net) Received: from nlpi012.sbcis.sbc.com (nlpi012.sbcis.sbc.com [207.115.36.41]) by mx1.freebsd.org (Postfix) with ESMTP id 555E213C442 for ; Thu, 25 Jan 2007 01:18:42 +0000 (UTC) (envelope-from kbyanc@posi.net) X-ORBL: [71.141.251.198] Received: from gateway.posi.net (adsl-71-141-251-198.dsl.snfc21.pacbell.net [71.141.251.198]) by nlpi012.sbcis.sbc.com (8.13.8 out.dk.spool/8.13.8) with ESMTP id l0P12fv8031249; Wed, 24 Jan 2007 19:02:42 -0600 Received: from localhost (localhost [127.0.0.1]) by gateway.posi.net (Postfix) with ESMTP id 4715275E002; Wed, 24 Jan 2007 17:02:36 -0800 (PST) Date: Wed, 24 Jan 2007 17:02:35 -0800 (PST) From: Kelly Yancey To: Max Laier In-Reply-To: <200701212033.34914.max@love2party.net> Message-ID: <20070124164949.P16327@gateway.posi.net> References: <20070121155510.C23922@delplex.bde.org> <200701210809.27770.max@love2party.net> <20070121215054.C24780@delplex.bde.org> <200701212033.34914.max@love2party.net> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Cc: freebsd-net@freebsd.org Subject: Re: slow writes on nfs with bge devices X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 25 Jan 2007 01:18:42 -0000 On Sun, 21 Jan 2007, Max Laier wrote: > On Sunday 21 January 2007 13:25, Bruce Evans wrote: > > On Sun, 21 Jan 2007, Max Laier wrote: > > > On Sunday 21 January 2007 07:25, Bruce Evans wrote: > > >> nfs writes much less well with bge NICs than with other NICs (sk, > > >> fxp, > > > > > > Do you use hardware checksumming on the bge? There is an XXX in > > > bge_start_locked() that looks a bit suspicious to me. > > > > I use the default for that. Wouldn't checksum problems show up as > > errors somwhere? > > Did you look at the code in question? It is concerned with fragmented > packet chains (which NFS over UDP usually generated) and only commits to > sending them, if there are enough descriptors available at once. This > can easily explain burstyness. > > Can you just try to disable the delayed checksums via "ifconfig -txcsum"? > Should be an easy enough test. > I realize that Bruce has already identified the problem as being with the cabling, however I wanted to add a warning that disabling hardware checksums for bge cards is not a good idea. You can find my analysis of data corruption bugs caused by using bge cards without checksum offloading in the archives: http://lists.freebsd.org/pipermail/freebsd-net/2004-January/002530.html Kelly -- Kelly Yancey - kbyanc@posi.net | kelly@nttmcl.com