From owner-freebsd-current@freebsd.org Wed Nov 1 00:47:06 2017 Return-Path: Delivered-To: freebsd-current@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 590F2E48786 for ; Wed, 1 Nov 2017 00:47:06 +0000 (UTC) (envelope-from yuripv@gmx.com) Received: from mout.gmx.net (mout.gmx.net [212.227.15.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "mout.gmx.net", Issuer "TeleSec ServerPass DE-2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id CD0F86B4A4 for ; Wed, 1 Nov 2017 00:47:05 +0000 (UTC) (envelope-from yuripv@gmx.com) Received: from thor.xvoid.org ([94.233.210.201]) by mail.gmx.com (mrgmx002 [212.227.17.184]) with ESMTPSA (Nemesis) id 0McEkx-1dtXsF47ol-00JdRd; Wed, 01 Nov 2017 01:46:49 +0100 Subject: Re: NFSv3 issues with latest -current To: Rick Macklem , "Rodney W. Grimes" Cc: Cy Schubert , freebsd-current References: <201710311646.v9VGknFO082029@pdx.rh.CN85.dnsmgr.net> From: Yuri Pankov Message-ID: <1c0ca4f6-04ee-944c-e910-3a10ada87d9e@gmx.com> Date: Wed, 1 Nov 2017 03:46:46 +0300 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.13; rv:52.0) Gecko/20100101 Thunderbird/52.4.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Provags-ID: V03:K0:1d/UG+ngGphX83VJpnbGi1wYnEGhMY5gY8eYxEGKzSict7o7klq 0uITXThYrEAgtvf2V4c85EbiJabBLaE91aubfx4ger10dg4tJ6BdPuVUlvXjDcwtK/Rg150 vrPkO20b6kYeWms6xLDfJ/x6QQsMbu8um4RQ8eK+lZLHQN3sRrzKGomQvnu3WefRb8hoR9p O9GKfwAsfOIGMR7EDd9jg== X-UI-Out-Filterresults: notjunk:1;V01:K0:oFllo50LJy0=:GCJ12ZIewi8/MwtXb558NY Dc2KmMGDgRPPrsFbMJPjEO91gGnS+evN83pInplvzglOolwWNueBOx91oawU6qW5MZU/Y5KvK 8ws5laPm1c72vHKFPToEKmRZvVc5L3cLKpQhntKThOXSazV6a76YQOpr/XoeDqU+Ha/gtFJEQ KTv8I/DtNac0bJPQsBk1ptBlQ58qtdWcFTr5GXpYQWRoXa5duqXtKPahmSQ27KpJAXViK/5Ww wLjNz8+pdSL0omrXshiYR7Tkv3Mxmni1+5MOEbZddLWOLnJSS+HlA6CcGMatoz/4pXS6/moCh GMv9SclIP/rX8W3sOOWR38VWKnk3dpD+deSj6xPmReIEzIG2kSre8iY1SQKKqEushjxA0Zq89 Ul3jP7tq7GAERdu3E6l65ye/oPRbG3L19W3nhaeNEJEv5Bhs+wnq/1Tbxbhl810ICuVWoUrQO gj8XF6B7mvCaaCSAhe6391nn8EwGX5zWNrTF9ujqw4Fa8WbFP0iih/P2JZMWGbOvGho0oo4wQ NBfd2PMgjdMPz71xK7YsAzBZ9Onw7C6PCIGHxL45rSXHiGTnHYpx7IqE5zaJiBqFo3Hk+sjvC zxyed1ER/DrzjqUGfYt+GJ1Yt6di3WQb3iH5+CLz1hebCgTumV1qhw4EkCAfyxIXZyKZTXbha 6g1jUePbBcxee7PPPda1qAeB3WGU3/bD+NfIYMLVTU0DZTt5w5FPGAr5od6g+mCqf1KLgvspx +ZCQXIPz5pTDLqmmQMnhwqrCacwubonhNltycKf0ormkRHa5pQ0mzjUGNURPyxxqEeskmJW4f tq7F7sPnYVMsmTbKVYvHhzeN2phP2JTnxD3jT/LzK1aDZ2/Qwg= X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 01 Nov 2017 00:47:06 -0000 On Wed, 1 Nov 2017 00:27:50 +0000, Rick Macklem wrote: > Rodney W. Grimes wrote: > [stuff snipped] >> I wrote: >>> Btw, NFS often causes this because... >>> - Typically TSO is limited to a 64K packet (including TCP/IP and MAC headers). >>> - When NFS does reading/writing, it will do 64K + NFS, TCP/IP and MAC headers >>> for an RPC (or a multiple of 64K like 128K). >>> --> This results in tcp_output() generating a 64K TSO segment followed by a >>> small TCP segment (since another RPC message doesn;t usually end up >>> queued quickly enough to fill in the rest of the second TCP segment). >>> - Also, at the end of file, you can get an RPC which is just under 64K including >>> NFS and TCP/IP headers. (The drivers often broke when adding the MAC >>> header bumped this case to > 64K.) >>> >>> Thanks go to Yuri for diagnosing this, rick >> >> Just a thought, not asking anyone to write one :-) >> >> It would be handy to have some sh(1) scripts that can exercise this bug >> case and have it readily avaliable to network driver authors for testing >> the tso (or other large segment) code. > You can't easily reproduce this from userland. It depends on the way NFS fills in > the mbuf chain for I/O RPCs. (iSCSI does something similar.) > > However, if your shell script does an NFS mount and the writes/reads a > file just under 64K in size on the mount... Yes, I should be able to test this, it's not a production in any case. And just in case, it's not related to nfs, sorry for jumping to guesses, Rick, scp behaves the same, giving a fair transfer rate of 10kbps, and 10MBps with that change backed out.