From owner-freebsd-net@FreeBSD.ORG Sat Jan 4 19:20:29 2014 Return-Path: Delivered-To: freebsd-net@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id D87487E4 for ; Sat, 4 Jan 2014 19:20:29 +0000 (UTC) Received: from mail-yh0-x22d.google.com (mail-yh0-x22d.google.com [IPv6:2607:f8b0:4002:c01::22d]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (No client certificate requested) by mx1.freebsd.org (Postfix) with ESMTPS id 8B80519B9 for ; Sat, 4 Jan 2014 19:20:29 +0000 (UTC) Received: by mail-yh0-f45.google.com with SMTP id v1so3379952yhn.32 for ; Sat, 04 Jan 2014 11:20:28 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=wemm.org; s=google; h=message-id:date:from:organization:user-agent:mime-version:to:cc :subject:references:in-reply-to:content-type; bh=oMufCLOzru7bhrRY3zvSIPPdRXSrO3MOPynzwD3HT1A=; b=YzPGNZCJvjgXJixt6LiKZsjcwB6YWhRUjP3A33DAMSwRY7A24s76Evl+5uZJ+/O6Ii zG2wqC/FERzv67LbjC1BPqFgDs/WYU1htuSC5UbWb7Y6c/iyC6+APy/bDgy13cp+irf0 DvGjeEbrv4CyPj3u48ruNVNP82017s7ElEUC4= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:message-id:date:from:organization:user-agent :mime-version:to:cc:subject:references:in-reply-to:content-type; bh=oMufCLOzru7bhrRY3zvSIPPdRXSrO3MOPynzwD3HT1A=; b=KDzu5l8qo3wPrhwubOO5DKheFdztFBp7/3Gw4IndExuRxOcSXEKhwMkfph39hKZ6JA SXMmIwVaeS+neVrK5ca+A611fSB8hgLS8tM7jsc8+4FTgJdf1pby7welXtPlt4+G7jqp 25iGIlqXTos+UMl8CZVfSCjZxdpF+PmcmiQf3Sh1smx1eXi7hYnCsNS07ZtWV1x0P8Cz UnfAcycrGjfFcwgXWR9e82BNKz4iPQY6wICnAFp9CI6FzFFb0AgiVgs5bc8ReIAv9+6Y bgw61lQ1SWnJ5bxIYwVGj8vXW/AcBM/2TnuDpW6rr47DU6U4zqH9HqAaaLKueriPud7b 5uUw== X-Gm-Message-State: ALoCoQmm8kIiDipGQ/ZgZa1pH5BEMdcwTHMc7KDJlsouVj9JzfIaX1aB3TrrkFutIEvL1L36COhi X-Received: by 10.236.18.226 with SMTP id l62mr3038585yhl.105.1388863228838; Sat, 04 Jan 2014 11:20:28 -0800 (PST) Received: from hackintosh.wemm.org ([2601:9:e80:770:7885:d41f:f3a8:eada]) by mx.google.com with ESMTPSA id m9sm9986142yha.2.2014.01.04.11.20.14 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Sat, 04 Jan 2014 11:20:14 -0800 (PST) Message-ID: <52C85EED.801@wemm.org> Date: Sat, 04 Jan 2014 11:20:13 -0800 From: Peter Wemm Organization: World Domination in progress. User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.9; rv:24.0) Gecko/20100101 Thunderbird/24.2.0 MIME-Version: 1.0 To: freebsd-net@freebsd.org Subject: Re: Long-haul problems - connections stuck in slow start References: <52C85537.7080307@wemm.org> In-Reply-To: <52C85537.7080307@wemm.org> X-Enigmail-Version: 1.6 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="2qhRgDNowvCSusNohUdo2nMLk15gglXSo" Cc: Gavin Atkinson , andre@freebsd.org, Peter Wemm X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.17 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 04 Jan 2014 19:20:30 -0000 This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --2qhRgDNowvCSusNohUdo2nMLk15gglXSo Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable On 1/4/14, 10:38 AM, Peter Wemm wrote: > We're seeing some unfortunate misbehavior with tcp over an intercontine= ntal > link. I forgot to mention, the socket buffers have been generously tuned for th= ese endpoints. They don't seem to be being used while the sender is in some s= ort of limited transmit mode. When reading the tcpdumps, keep in mind the window scaling factor is 11 a= nd that's wasn't captured in the session. You'll have to manually compensat= e when reading the mid-session dumps. XXX footnote: It seems turning SACK off makes a huge difference for this= connection. The server must have been running with sack disabled when it= was working and hadn't been saved in sysctl.conf. Turning sack off on the= server again has raised the throughput from 8K/sec to 32MB/sec. That's a= nice 400x speedup. I'm investigating. --=20 Peter Wemm - peter@wemm.org; peter@FreeBSD.org; peter@yahoo-inc.com; KI6F= JV UTF-8: for when a ' just won\342\200\231t do. --2qhRgDNowvCSusNohUdo2nMLk15gglXSo Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iEYEARECAAYFAlLIXu0ACgkQFRKuUnJ3cX8ORgCdGqZX/IMlh5I8TScjlHeXhcNb cFMAmgKr7VehEc8qO78XQngQJLycdyXT =yPlr -----END PGP SIGNATURE----- --2qhRgDNowvCSusNohUdo2nMLk15gglXSo--