From owner-freebsd-performance@FreeBSD.ORG Fri Dec 11 15:16:10 2009 Return-Path: Delivered-To: freebsd-performance@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id DAA39106566B for ; Fri, 11 Dec 2009 15:16:10 +0000 (UTC) (envelope-from prvs=1596b04d6d=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 5FBCD8FC08 for ; Fri, 11 Dec 2009 15:16:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=simple; d=multiplay.co.uk; s=Multiplay; t=1260543927; x=1261148727; q=dns/txt; h=Received: Message-ID:From:To:Subject:Date:MIME-Version:Content-Type: Content-Transfer-Encoding; bh=DzqoRA0YNasI9VxTsPPqqMCiWa4NL3Z/ZW wWnlnwEbs=; b=bEe/DEB2mvY20jvs3+7joCjCgPsGt6YSBn5EjbMc8soEgPQfvn LcEDl1rXFXlXp4pG5siVr9UEHR4CAn7ZjHPLE7lIDzuBy1YONyv7pTx1d4bHIWsO hemiHWrxgQIiSmHEhmUB+rDMWYOZ9tL7LpOSSi3AnM5S6oPcTK/MCCBtI= X-MDAV-Processed: mail1.multiplay.co.uk, Fri, 11 Dec 2009 15:05:27 +0000 Received: from r2d2 by mail1.multiplay.co.uk (MDaemon PRO v10.0.4) with ESMTP id md50008847478.msg for ; Fri, 11 Dec 2009 15:05:26 +0000 X-Spam-Processed: mail1.multiplay.co.uk, Fri, 11 Dec 2009 15:05:26 +0000 (not processed: message from trusted or authenticated source) X-Authenticated-Sender: Killing@multiplay.co.uk X-MDRemoteIP: 213.123.247.160 X-Return-Path: prvs=1596b04d6d=killing@multiplay.co.uk X-Envelope-From: killing@multiplay.co.uk X-MDaemon-Deliver-To: freebsd-performance@freebsd.org Message-ID: From: "Steven Hartland" To: Date: Fri, 11 Dec 2009 15:05:04 -0000 MIME-Version: 1.0 Content-Type: text/plain; format=flowed; charset="iso-8859-1"; reply-type=original Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.5843 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5579 Subject: Significant performance regression for increased maxsockbuf on 8.0-RELEASE X-BeenThere: freebsd-performance@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Performance/tuning List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 11 Dec 2009 15:16:11 -0000 As noted in the FreeBSD TCP tuning and performance thread here: http://lists.freebsd.org/pipermail/freebsd-performance/2009-December/003909.html There seems to be a significant performance drop when using 8.0 vs 7.0 after digging around this seems to be caused by the use of increased kern.ipc.maxsockbuf Using the default value ( 262144 ) I see the following iperf results: iperf -t 10 -c server1 -w 2.5M -l 2.5M ------------------------------------------------------------ Client connecting to db3, TCP port 5001 TCP window size: 65.0 KByte (WARNING: requested 2.50 MByte) ------------------------------------------------------------ [ 3] local 85.236.96.66 port 50848 connected with 85.236.96.42 port 5001 [ ID] Interval Transfer Bandwidth [ 3] 0.0-10.0 sec 1.09 GBytes 935 Mbits/sec With anything larger than that the rate drops off significantly e.g. 282144 gives:- iperf -t 10 -c db3 -w 2.5M -l 2.5M ------------------------------------------------------------ Client connecting to db3, TCP port 5001 TCP window size: 65.0 KByte (WARNING: requested 2.50 MByte) ------------------------------------------------------------ [ 3] local 85.236.96.66 port 25867 connected with 85.236.96.42 port 5001 [ ID] Interval Transfer Bandwidth [ 3] 0.0-10.0 sec 778 MBytes 651 Mbits/sec and 302144 we're down to just under half the baseline / line rate iperf -t 10 -c db3 -w 2.5M -l 2.5M ------------------------------------------------------------ Client connecting to db3, TCP port 5001 TCP window size: 65.0 KByte (WARNING: requested 2.50 MByte) ------------------------------------------------------------ [ 3] local 85.236.96.66 port 12506 connected with 85.236.96.42 port 5001 [ ID] Interval Transfer Bandwidth [ 3] 0.0-10.0 sec 588 MBytes 492 Mbits/sec Any ideas why using window sizes above 65K results in such poor performance on 8.0? 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.