From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 83B51C352AA for ; Wed, 2 Oct 2019 01:41:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5AC4320B7C for ; Wed, 2 Oct 2019 01:41:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729611AbfJBBlh (ORCPT ); Tue, 1 Oct 2019 21:41:37 -0400 Received: from shards.monkeyblade.net ([23.128.96.9]:55412 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727782AbfJBBlh (ORCPT ); Tue, 1 Oct 2019 21:41:37 -0400 Received: from localhost (unknown [IPv6:2603:3023:50c:85e1:b5c5:ae11:3e54:6a07]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) (Authenticated sender: davem-davemloft) by shards.monkeyblade.net (Postfix) with ESMTPSA id 2616A14DAB32B; Tue, 1 Oct 2019 18:41:36 -0700 (PDT) Date: Tue, 01 Oct 2019 21:41:35 -0400 (EDT) Message-Id: <20191001.214135.98815209147906561.davem@davemloft.net> To: edumazet@google.com Cc: netdev@vger.kernel.org, ncardwell@google.com, eric.dumazet@gmail.com, ycheng@google.com, marek@cloudflare.com Subject: Re: [PATCH net] tcp: adjust rto_base in retransmits_timed_out() From: David Miller In-Reply-To: <20190930224444.77901-1-edumazet@google.com> References: <20190930224444.77901-1-edumazet@google.com> X-Mailer: Mew version 6.8 on Emacs 26.1 Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Tue, 01 Oct 2019 18:41:36 -0700 (PDT) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Eric Dumazet Date: Mon, 30 Sep 2019 15:44:44 -0700 > The cited commit exposed an old retransmits_timed_out() bug > which assumed it could call tcp_model_timeout() with > TCP_RTO_MIN as rto_base for all states. > > But flows in SYN_SENT or SYN_RECV state uses a different > RTO base (1 sec instead of 200 ms, unless BPF choses > another value) > > This caused a reduction of SYN retransmits from 6 to 4 with > the default /proc/sys/net/ipv4/tcp_syn_retries value. > > Fixes: a41e8a88b06e ("tcp: better handle TCP_USER_TIMEOUT in SYN_SENT state") > Signed-off-by: Eric Dumazet Applied and queued up for -stable.