Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932666Ab1ESGmx (ORCPT ); Thu, 19 May 2011 02:42:53 -0400 Received: from mail-yi0-f46.google.com ([209.85.218.46]:64616 "EHLO mail-yi0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932586Ab1ESGmv (ORCPT ); Thu, 19 May 2011 02:42:51 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc:content-type; b=NFkl9eN5ahm4hdDk4vW2mFRNDIs2TSIihRURm1vN2UFOwBdWDq2m7G+HqI0yOUsEFF msOBfQz3lZ8WHS7MwmPogumBZYsmm2X060ZiUgHMKibqUJTybpZSP10KNHCFr/hh9qAB xDGVEDtahubqqSpckfS5yt6WLdxQJkFS+CIeQ= MIME-Version: 1.0 In-Reply-To: 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> From: tsuna Date: Wed, 18 May 2011 23:42:30 -0700 Message-ID: Subject: Re: [PATCH] tcp: Implement a two-level initial RTO as per draft RFC 2988bis-02. To: Alexander Zimmermann 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-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1183 Lines: 28 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. -- Benoit "tsuna" Sigoure Software Engineer @ www.StumbleUpon.com -- 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/