Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933564Ab1ESQ4F (ORCPT ); Thu, 19 May 2011 12:56:05 -0400 Received: from mta-2.ms.rz.RWTH-Aachen.DE ([134.130.7.73]:41266 "EHLO mta-2.ms.rz.rwth-aachen.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933163Ab1ESQ4D (ORCPT ); Thu, 19 May 2011 12:56:03 -0400 MIME-version: 1.0 X-IronPort-AV: E=Sophos;i="4.65,238,1304287200"; d="sig'?scan'208";a="113457316" Subject: Re: [PATCH] tcp: Implement a two-level initial RTO as per draft RFC 2988bis-02. Content-type: multipart/signed; protocol="application/pgp-signature"; micalg=pgp-sha1; boundary=Apple-Mail-15--1048038099 From: Alexander Zimmermann In-reply-to: Date: Thu, 19 May 2011 18:55:59 +0200 Cc: Hagen Paul Pfeifer , David Miller , kuznet@ms2.inr.ac.ru, pekkas@netcore.fi, jmorris@namei.org, yoshfuji@linux-ipv6.org, kaber@trash.net, eric.dumazet@gmail.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Content-transfer-encoding: 7bit Message-id: <1456193D-84D1-46E2-B930-8FD0A5B8C409@comsys.rwth-aachen.de> References: <1305771744-83951-1-git-send-email-tsunanet@gmail.com> <20110518.223622.1525088601595365235.davem@davemloft.net> <20110519.001426.2119532755281545481.davem@davemloft.net> <9DC9A4D5-8E16-4361-B323-C92D563171A1@comsys.rwth-aachen.de> <8C5DF277-320D-4DEB-A133-EEC301DE58DC@comsys.rwth-aachen.de> To: tsuna X-Pgp-Agent: GPGMail 1.3.3 X-Mailer: Apple Mail (2.1084) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2553 Lines: 75 This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --Apple-Mail-15--1048038099 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=iso-8859-1 Am 19.05.2011 um 18:40 schrieb tsuna: > On Thu, May 19, 2011 at 1:02 AM, Hagen Paul Pfeifer = wrote: >> So yes, it CAN be wise to choose other lower/upper bounds. But keep = in >> mind that we should NOT artificial limit ourself. I can image data = center >> scenarios where a initial RTO of <1 match perfectly. >=20 > Yes that's exactly the point I was trying to make when talking to > Alexander offline. On today's Internet, RTTs are easily in the > hundreds of ms, and initRTO is 3s, so there's 2 orders of magnitude of > difference. In my environment, Exactly. This is the point. It's *your* environment. However, TCP is general purpose. And for the wider internet 1s is know to be save. See = the measurements in the draft that Mark Allman run. > if my RTT is ~2=B5s, an initRTO of 200ms > means that there's a gap of 6 orders of magnitude (!). Currently, initRTO is 3s. So you the gap is even larger.=20 > And yes, > although I don't work for High Frequency Trading companies in Wall > Street, I'm already buying switches full of line-rate 10Gb ports with > a port-to-port latency of 500ns for L2/L3 forwarding/switching. I > expect this kind of network gear will quickly become prevalent in > datacenter/backend environments. >=20 > --=20 > Benoit "tsuna" Sigoure > Software Engineer @ www.StumbleUpon.com // // Dipl.-Inform. Alexander Zimmermann // Department of Computer Science, Informatik 4 // RWTH Aachen University // Ahornstr. 55, 52056 Aachen, Germany // phone: (49-241) 80-21422, fax: (49-241) 80-22222 // email: zimmermann@cs.rwth-aachen.de // web: http://www.umic-mesh.net // --Apple-Mail-15--1048038099 content-type: application/pgp-signature; x-mac-type=70674453; name=PGP.sig content-description: Signierter Teil der Nachricht content-disposition: inline; filename=PGP.sig content-transfer-encoding: 7bit -----BEGIN PGP SIGNATURE----- Version: GnuPG/MacGPG2 v2.0.17 (Darwin) Comment: GPGTools - http://gpgtools.org iEYEARECAAYFAk3VS6AACgkQdyiq39b9uS7VNwCg/rb5DvGzmcKnWXXNJx+ikMqp aVcAnArVGhoWtXF8Sz6DGG8aY9+UrGhm =Jzc5 -----END PGP SIGNATURE----- --Apple-Mail-15--1048038099-- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/