Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762835AbXJMWiQ (ORCPT ); Sat, 13 Oct 2007 18:38:16 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753728AbXJMWiB (ORCPT ); Sat, 13 Oct 2007 18:38:01 -0400 Received: from userg501.nifty.com ([202.248.238.81]:32778 "EHLO userg501.nifty.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753782AbXJMWiA (ORCPT ); Sat, 13 Oct 2007 18:38:00 -0400 DomainKey-Signature: a=rsa-sha1; s=userg501; d=nifty.com; c=nofws; q=dns; h=date:from:to:cc:subject:message-id:in-reply-to:references: x-mailer:mime-version:content-type:content-transfer-encoding; b=elcfT1lj3QGE0DICqYMDVgEVQejQkyLhPVQNikpU2gbidbcioFcLaQhKx8ml+eHkr X4+6oOWmD2Afst8SJp0MA== X-Nifty-SrcIP: [219.104.15.224] Date: Sun, 14 Oct 2007 07:36:58 +0900 From: Komuro To: davem@sunset.davemloft.net Cc: linux-kernel@vger.kernel.org Subject: [NOT VERY SAFE] [TCP]: Set initial_ssthresh default to zero in Cubic and BIC. Message-Id: <20071014073658.d4352b8c.komurojun@nifty.com> In-Reply-To: <20071006132601.f944f461.komurojun@nifty.com> References: <20071006132601.f944f461.komurojun@nifty.com> X-Mailer: Sylpheed 2.3.1 (GTK+ 2.10.11; i386-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1977 Lines: 60 Dear David The patch "[TCP]: Set initial_ssthresh default to zero in Cubic and BIC." is not very safe. With this patch, ftp-transfer stops in my system. (vsftpd-2.0.5-8) Please revert this patch. Best Regards Komuro >commit 66e1e3b20cbbf99da63e6c1af0fc6d39c2ed099a >Author: David S. Miller >Date: Wed Jun 13 01:03:53 2007 -0700 > > [TCP]: Set initial_ssthresh default to zero in Cubic and BIC. > > Because of the current default of 100, Cubic and BIC perform very > poorly compared to standard Reno. > > In the worst case, this change makes Cubic and BIC as aggressive as > Reno. So this change should be very safe. > > Signed-off-by: David S. Miller > >diff --git a/net/ipv4/tcp_bic.c b/net/ipv4/tcp_bic.c >index 281c9f9..dd9ef65 100644 >--- a/net/ipv4/tcp_bic.c >+++ b/net/ipv4/tcp_bic.c >@@ -29,7 +29,7 @@ static int fast_convergence = 1; > static int max_increment = 16; > static int low_window = 14; > static int beta = 819; /* = 819/1024 (BICTCP_BETA_SCALE) */ >-static int initial_ssthresh = 100; >+static int initial_ssthresh; > static int smooth_part = 20; > > module_param(fast_convergence, int, 0644); >diff --git a/net/ipv4/tcp_cubic.c b/net/ipv4/tcp_cubic.c >index 1422448..ebfaac2 100644 >--- a/net/ipv4/tcp_cubic.c >+++ b/net/ipv4/tcp_cubic.c >@@ -29,7 +29,7 @@ > static int fast_convergence __read_mostly = 1; > static int max_increment __read_mostly = 16; > static int beta __read_mostly = 819; /* = 819/1024 (BICTCP_BETA_SCALE) */ >-static int initial_ssthresh __read_mostly = 100; >+static int initial_ssthresh __read_mostly; > static int bic_scale __read_mostly = 41; > static int tcp_friendliness __read_mostly = 1; > - 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/