From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: Re: [PATCH net-next] tcp: reset timer after any SYNACK retransmit Date: Mon, 29 Apr 2013 11:54:19 -0700 Message-ID: <1367261659.8964.332.camel@edumazet-glaptop> References: <1367261091-28052-1-git-send-email-ycheng@google.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: davem@davemloft.net, ncardwell@google.com, edumazet@google.com, hagen@jauu.net, netdev@vger.kernel.org To: Yuchung Cheng Return-path: Received: from mail-pa0-f48.google.com ([209.85.220.48]:47417 "EHLO mail-pa0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755946Ab3D2SyX (ORCPT ); Mon, 29 Apr 2013 14:54:23 -0400 Received: by mail-pa0-f48.google.com with SMTP id lb1so1910472pab.21 for ; Mon, 29 Apr 2013 11:54:22 -0700 (PDT) In-Reply-To: <1367261091-28052-1-git-send-email-ycheng@google.com> Sender: netdev-owner@vger.kernel.org List-ID: On Mon, 2013-04-29 at 11:44 -0700, Yuchung Cheng wrote: > Linux immediately returns SYNACK on (spurious) SYN retransmits, but > keeps the SYNACK timer running independently. Thus the timer may > fire right after the SYNACK retransmit and causes a SYN-SYNACK > cross-fire burst. > > Adopt the fast retransmit/recovery idea in established state by > re-arming the SYNACK timer after the fast (SYNACK) retransmit. The > timer may fire late up to 500ms due to the current SYNACK timer wheel, > but it's OK to be conservative when network is congested. Eric's new > listener design should address this issue. > > Signed-off-by: Yuchung Cheng > --- Acked-by: Eric Dumazet