From mboxrd@z Thu Jan 1 00:00:00 1970 From: Douglas Leith Subject: Re the default linux tcp algorithm being changed from bic to cubic. Date: Thu, 28 Sep 2006 11:07:18 +0100 Message-ID: <451B9ED6.9090208@nuim.ie> Mime-Version: 1.0 Content-Type: TEXT/PLAIN Content-Transfer-Encoding: 7BIT Cc: Douglas Leith Return-path: Received: from mail.nuim.ie ([149.157.1.19]:52221 "EHLO LARCH.MAY.IE") by vger.kernel.org with ESMTP id S1751794AbWI1KI6 (ORCPT ); Thu, 28 Sep 2006 06:08:58 -0400 Received: from [10.220.3.214] ([149.157.192.252]) by NUIM.IE (PMDF V6.2-X17 #30789) with ESMTPA id <01M7Q5PTG07G00VAW2@NUIM.IE> for netdev@vger.kernel.org; Thu, 28 Sep 2006 11:09:00 +0000 (GMT) To: shemminger@osdl.org, netdev , davem@davemloft.net Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Steve, I think we're all conscious of the fact that recent history contains quite a number of proposals for changes to tcp's congestion control algorithm for high bandwidth-delay product paths that on closer inspection have proved problematic in one way or another. It seems to be a hard problem to solve, so maybe that's fair enough and hopefully we'll end up with a workable solution soon. Where I'm coming from here though is that bic was made the linux default a year or so ago at a time when there were essentially no tests available on its performance other than the infocom paper by Injong. Subsequent tests have since highlighted a bunch of issues with bic. To my knowledge, we're currently in a similar situation with cubic as we were with bic back then i.e. essentially no independent tests investigating its behaviour. Of course I know Injong has posted some test results, but these are hardly independent as he's the author of both bic and cubic. Have there perhaps been private tests carried out (e.g. by osdl) ? If so, would it be possible to make them public ? If not, well that would be good to know too. Doug Hamilton Institute www.hamilton.ie ------- Original Message -------- Subject: [TCP]: make cubic the default Date: Tue, 26 Sep 2006 00:59:56 GMT From: Linux Kernel Mailing List To: git-commits-head@vger.kernel.org commit 597811ec167fa01c926a0957a91d9e39baa30e64 tree 24e6ce26a4464d21993f2cd17dbdb9aec13360ab parent 3d2573f7ebe507e372a23cdd3c8b03305d6e90aa author Stephen Hemminger 1159153983 -0700 committer David S. Miller 1159153983 -0700 [TCP]: make cubic the default Change default congestion control used from BIC to the newer CUBIC which it the successor to BIC but has better properties over long delay links. Signed-off-by: Stephen Hemminger Signed-off-by: David S. Miller net/ipv4/Kconfig | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/net/ipv4/Kconfig b/net/ipv4/Kconfig index 1bbc368..30af4a4 100644 --- a/net/ipv4/Kconfig +++ b/net/ipv4/Kconfig @@ -455,7 +455,7 @@ menuconfig TCP_CONG_ADVANCED modules. Nearly all users can safely say no here, and a safe default - selection will be made (BIC-TCP with new Reno as a fallback). + selection will be made (CUBIC with new Reno as a fallback). If unsure, say N. @@ -463,7 +463,7 @@ if TCP_CONG_ADVANCED config TCP_CONG_BIC tristate "Binary Increase Congestion (BIC) control" - default y + default m ---help--- BIC-TCP is a sender-side only change that ensures a linear RTT fairness under large windows while offering both scalability and @@ -477,7 +477,7 @@ config TCP_CONG_BIC config TCP_CONG_CUBIC tristate "CUBIC TCP" - default m + default y ---help--- This is version 2.0 of BIC-TCP which uses a cubic growth function among other techniques. @@ -574,7 +574,7 @@ config TCP_CONG_VENO choice prompt "Default TCP congestion control" - default DEFAULT_BIC + default DEFAULT_CUBIC help Select the TCP congestion control that will be used by default for all connections. @@ -601,7 +601,7 @@ endchoice endif -config TCP_CONG_BIC +config TCP_CONG_CUBIC tristate depends on !TCP_CONG_ADVANCED default y @@ -614,7 +614,7 @@ config DEFAULT_TCP_CONG default "vegas" if DEFAULT_VEGAS default "westwood" if DEFAULT_WESTWOOD default "reno" if DEFAULT_RENO - default "bic" + default "cubic" source "net/ipv4/ipvs/Kconfig" - To unsubscribe from this list: send the line "unsubscribe git-commits-head" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html