From owner-freebsd-net@FreeBSD.ORG Tue Aug 2 12:56:49 2011 Return-Path: Delivered-To: freebsd-net@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id E0D4C1065674; Tue, 2 Aug 2011 12:56:49 +0000 (UTC) (envelope-from prvs=119502d6cc=killing@multiplay.co.uk) Received: from mail1.multiplay.co.uk (mail1.multiplay.co.uk [85.236.96.23]) by mx1.freebsd.org (Postfix) with ESMTP id 099518FC28; Tue, 2 Aug 2011 12:56:48 +0000 (UTC) X-MDAV-Processed: mail1.multiplay.co.uk, Tue, 02 Aug 2011 13:56:16 +0100 X-Spam-Processed: mail1.multiplay.co.uk, Tue, 02 Aug 2011 13:56:16 +0100 X-Spam-Checker-Version: SpamAssassin 3.2.5 (2008-06-10) on mail1.multiplay.co.uk X-Spam-Level: X-Spam-Status: No, score=-5.0 required=6.0 tests=USER_IN_WHITELIST shortcircuit=ham autolearn=disabled version=3.2.5 Received: from r2d2 ([188.220.16.49]) by mail1.multiplay.co.uk (mail1.multiplay.co.uk [85.236.96.23]) (MDaemon PRO v10.0.4) with ESMTP id md50014433957.msg; Tue, 02 Aug 2011 13:56:15 +0100 X-MDRemoteIP: 188.220.16.49 X-Return-Path: prvs=119502d6cc=killing@multiplay.co.uk X-Envelope-From: killing@multiplay.co.uk Message-ID: From: "Steven Hartland" To: "Steven Hartland" , "Andre Oppermann" References: <1F95A4C2D54E4F369830143CBDB5FF86@multiplay.co.uk><4E37C0F2.4080004@freebsd.org><2B063B6D95AA4C27B004C50D96393F91@multiplay.co.uk> Date: Tue, 2 Aug 2011 13:56:48 +0100 MIME-Version: 1.0 Content-Type: text/plain; format=flowed; charset="iso-8859-1"; reply-type=response Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.5931 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.6109 Cc: freebsd-net@freebsd.org, lstewart@freebsd.org Subject: Re: tcp failing to recover from a packet loss under 8.2-RELEASE? 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: Tue, 02 Aug 2011 12:56:50 -0000 ----- Original Message ----- From: "Steven Hartland" > I look forward to hearing peoples thoughts on what the actual fix > should be: increased default nmbclusters, decreased nmbclusters => > maxsegments divisor, or something else? Another useful piece of information is that even though maxsegments is set as a read only tuneable, it can be changed on the fly by changing kern.ipc.nmbclusters, which seems a bit strange tbh, so possibly an oversight there somewhere. Example:- sysctl net.inet.tcp.reass.maxsegments=16464 sysctl: oid 'net.inet.tcp.reass.maxsegments' is a read only tunable sysctl: Tunable values are set in /boot/loader.conf sysctl net.inet.tcp.reass.maxsegments net.inet.tcp.reass.maxsegments: 1680 sysctl kern.ipc.nmbclusters=262144 kern.ipc.nmbclusters: 25600 -> 262144 sysctl net.inet.tcp.reass.maxsegments net.inet.tcp.reass.maxsegments: 16464 Regards Steve ================================================ This e.mail is private and confidential between Multiplay (UK) Ltd. and the person or entity to whom it is addressed. In the event of misdirection, the recipient is prohibited from using, copying, printing or otherwise disseminating it or any information contained in it. In the event of misdirection, illegible or incomplete transmission please telephone +44 845 868 1337 or return the E.mail to postmaster@multiplay.co.uk.