Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932781Ab1ESGwP (ORCPT ); Thu, 19 May 2011 02:52:15 -0400 Received: from mta-2.ms.rz.RWTH-Aachen.DE ([134.130.7.73]:33241 "EHLO mta-2.ms.rz.rwth-aachen.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754845Ab1ESGwO (ORCPT ); Thu, 19 May 2011 02:52:14 -0400 MIME-version: 1.0 X-IronPort-AV: E=Sophos;i="4.65,236,1304287200"; d="sig'?scan'208";a="55171924" 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-35-1063216526 From: Alexander Zimmermann In-reply-to: Date: Thu, 19 May 2011 08:52:10 +0200 Cc: David Miller , kuznet@ms2.inr.ac.ru, pekkas@netcore.fi, jmorris@namei.org, yoshfuji@linux-ipv6.org, kaber@trash.net, hagen@jauu.net, eric.dumazet@gmail.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Content-transfer-encoding: 7bit Message-id: <8C5DF277-320D-4DEB-A133-EEC301DE58DC@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> 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: 2376 Lines: 70 This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --Apple-Mail-35-1063216526 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=us-ascii Am 19.05.2011 um 08:42 schrieb tsuna: > On Wed, May 18, 2011 at 11:36 PM, Alexander Zimmermann > wrote: >> If you set the initRTO=0.1s, it's good for me but bad for the rest of the >> world. That's the difference. >> >> Or do you want to implement a lower barrier of 1sec so that you can ensure >> that nobody set the initRTO lower than 1s? > > Oh, I see. Yes, there is a lower bound (and an upper bound) on what > values the kernel will accept as initRTO. In the patch "Implement a > two-level initial RTO as per draft RFC 2988bis-02" above, I re-used > TCP_RTO_MIN and TCP_RTO_MAX in net/ipv4/sysctl_net_ipv4.c in order to > prevent users from setting a minRTO that's outside this range. They > are defined as follows in tcp.h: > > #define TCP_RTO_MAX ((unsigned)(120*HZ)) > #define TCP_RTO_MIN ((unsigned)(HZ/5)) > > So we're talking about a [200ms ; 120s] range no matter what. Why is 200ms a valid lower bound for initRTO? I'm aware of measurements that 1s is save for Internet, but I don't know of any studies that 200ms is save... > > -- > 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-35-1063216526 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 iEYEARECAAYFAk3UvhsACgkQdyiq39b9uS47LQCeOTN8hzVZCY1fUd5Uj6h/PPZJ mQcAoOyDKx6mSIrxGO5SZ+z72zAMVPlP =G2Qm -----END PGP SIGNATURE----- --Apple-Mail-35-1063216526-- -- 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/