From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH v4 net-next] tcp: Change txhash on every SYN and RTO retransmit Date: Wed, 28 Sep 2016 07:52:59 -0400 (EDT) Message-ID: <20160928.075259.495409427572927438.davem@davemloft.net> References: <20160928020337.3057238-1-brakmo@fb.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, kernel-team@fb.com, eric.dumazet@gmail.com, ycheng@google.com, ncardwell@google.com To: brakmo@fb.com Return-path: Received: from shards.monkeyblade.net ([184.105.139.130]:33478 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752469AbcI1LxF (ORCPT ); Wed, 28 Sep 2016 07:53:05 -0400 In-Reply-To: <20160928020337.3057238-1-brakmo@fb.com> Sender: netdev-owner@vger.kernel.org List-ID: From: Lawrence Brakmo Date: Tue, 27 Sep 2016 19:03:37 -0700 > The current code changes txhash (flowlables) on every retransmitted > SYN/ACK, but only after the 2nd retransmitted SYN and only after > tcp_retries1 RTO retransmits. > > With this patch: > 1) txhash is changed with every SYN retransmits > 2) txhash is changed with every RTO. > > The result is that we can start re-routing around failed (or very > congested paths) as soon as possible. Otherwise application health > checks may fail and the connection may be terminated before we start > to change txhash. > > v4: Removed sysctl, txhash is changed for all RTOs > v3: Removed text saying default value of sysctl is 0 (it is 100) > v2: Added sysctl documentation and cleaned code > > Tested with packetdrill tests > > Signed-off-by: Lawrence Brakmo Applied, thanks.