From mboxrd@z Thu Jan 1 00:00:00 1970 From: tsuna Subject: Re: [PATCH] tcp: Implement a two-level initial RTO as per draft RFC 2988bis-02. Date: Thu, 19 May 2011 09:40:09 -0700 Message-ID: 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> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Alexander Zimmermann , 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 To: Hagen Paul Pfeifer Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On Thu, May 19, 2011 at 1:02 AM, Hagen Paul Pfeifer wr= ote: > So yes, it CAN be wise to choose other lower/upper bounds. But keep i= n > mind that we should NOT artificial limit ourself. I can image data ce= nter > scenarios where a initial RTO of <1 match perfectly. 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, if my RTT is ~2=B5s, an initRTO of 200m= s means that there's a gap of 6 orders of magnitude (!). 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 Benoit "tsuna" Sigoure Software Engineer @ www.StumbleUpon.com