From owner-freebsd-stable@FreeBSD.ORG Sat Nov 26 17:17:08 2011 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id D7852106566C for ; Sat, 26 Nov 2011 17:17:08 +0000 (UTC) (envelope-from lstewart@freebsd.org) Received: from lauren.room52.net (lauren.room52.net [210.50.193.198]) by mx1.freebsd.org (Postfix) with ESMTP id 9D3E98FC16 for ; Sat, 26 Nov 2011 17:17:08 +0000 (UTC) Received: from lstewart1.loshell.room52.net (ppp59-167-184-191.static.internode.on.net [59.167.184.191]) by lauren.room52.net (Postfix) with ESMTPSA id 96C3E7E8C5; Sun, 27 Nov 2011 04:17:07 +1100 (EST) Message-ID: <4ED11F13.8090501@freebsd.org> Date: Sun, 27 Nov 2011 04:17:07 +1100 From: Lawrence Stewart User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:7.0.1) Gecko/20111016 Thunderbird/7.0.1 MIME-Version: 1.0 To: George Mitchell References: <4ECEF6FD.5050006@freebsd.org> <4ED077BF.10205@freebsd.org> <4ED110FA.4060406@m5p.com> In-Reply-To: <4ED110FA.4060406@m5p.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Status: No, score=0.0 required=5.0 tests=UNPARSEABLE_RELAY autolearn=unavailable version=3.3.2 X-Spam-Checker-Version: SpamAssassin 3.3.2 (2011-06-06) on lauren.room52.net Cc: freebsd-stable@freebsd.org Subject: Re: TCP Reassembly Issues X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 26 Nov 2011 17:17:08 -0000 Hi George, On 11/27/11 03:16, George Mitchell wrote: > On 11/26/11 00:23, Lawrence Stewart wrote: >> [...] >> Could those who have reported the bug and are able to recompile their >> kernel to test a patch please try the following and report back to the >> list: >> >> http://people.freebsd.org/~lstewart/patches/misctcp/tcp_reass_plugzoneleak_10.x.r227986.patch >> >> [...] > Works for me! I'm now getting a sustained throughput of 7.4MB/s, > compared to 4.3MB/s on 8.2-STABLE and 3.2MB/s on 7.4-RELEASE, all on > the same hardware (HP notebook with re 100Mb/s interface, reading from > an 8.2-STABLE server with an alc 1000Mb/s interface, via two gigabit > switches). Good stuff. > But I'm still bemused that there should have been any TCP reassembly > going on. Doesn't that imply that there was packet fragmentation? My > network is uniformly 1500 byte MTU. -- George TCP reassembly refers to queuing packets received out of order until the missing segment is received i.e. not IP layer fragmentation related, but packet loss or packet reordering related. I guess something in your setup is dropping the odd packet which is why your NFS performance isn't closer to the 10+MB/s (I'm not sure how much overhead NFS adds, but ~12MB/s is max application-layer throughput of 100Mbps Ethernet so achievable NFS throughput should be a bit less than that) it could be if everything was peachy. siftr(4) and some tcpdumping on both client/server could probably help you figure out where you're dropping packets if you want to improve your current performance even further. Cheers, Lawrence