From owner-freebsd-net@freebsd.org Thu Apr 21 05:16:52 2016 Return-Path: Delivered-To: freebsd-net@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 9CD1AB16290 for ; Thu, 21 Apr 2016 05:16:52 +0000 (UTC) (envelope-from daemon-user@freebsd.org) Received: from reviews.nyi.freebsd.org (reviews.nyi.freebsd.org [IPv6:2610:1c1:1:607c::16:b]) by mx1.freebsd.org (Postfix) with ESMTP id 779BF17F5 for ; Thu, 21 Apr 2016 05:16:52 +0000 (UTC) (envelope-from daemon-user@freebsd.org) Received: by reviews.nyi.freebsd.org (Postfix, from userid 1346) id AFDECD3C2; Thu, 21 Apr 2016 05:16:51 +0000 (UTC) Date: Thu, 21 Apr 2016 05:16:51 +0000 To: freebsd-net@freebsd.org From: "lstewart (Lawrence Stewart)" Reply-to: D5872+325+9dea0574509cdbb3@reviews.freebsd.org Subject: [Differential] D5872: tcp: Don't prematurely drop receiving-only connections Message-ID: X-Priority: 3 X-Phabricator-Sent-This-Message: Yes X-Mail-Transport-Agent: MetaMTA X-Auto-Response-Suppress: All X-Phabricator-Mail-Tags: Thread-Topic: D5872: tcp: Don't prematurely drop receiving-only connections X-Herald-Rules: <64> X-Phabricator-To: X-Phabricator-To: X-Phabricator-To: X-Phabricator-To: X-Phabricator-To: X-Phabricator-To: X-Phabricator-To: X-Phabricator-To: X-Phabricator-To: X-Phabricator-To: X-Phabricator-To: X-Phabricator-To: X-Phabricator-To: X-Phabricator-Cc: X-Phabricator-Cc: X-Phabricator-Cc: Precedence: bulk In-Reply-To: References: Thread-Index: MmVmNzYzNzljOGQxMmM4MWI4MmNjYzcxMzczIFcYYkM= MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset="utf-8" X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.21 List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 21 Apr 2016 05:16:52 -0000 lstewart added a comment. In https://reviews.freebsd.org/D5872#128556, @hiren wrote: > In https://reviews.freebsd.org/D5872#128555, @lstewart wrote: > > > I thought that had been fixed ages ago... oops. > > > Fixed? i.e. doing something other than setting cwnd to 1 seg? Yes, but turns out it was a discussion I had privately with a colleague who never got around to creating the patch we discussed. >> It should be calling cc_cong_signal() with a new congestion type. > > Hum... tcp_quench() used to be there which essentially had this 1 line to set cwnd to 1 seg. > > Is there any (RFC) guidance for what to do in this situation? No, and it's an implementation detail that RFCs have no real business being concerned with either. Setting cwnd==maxseg is completely inappropriate though and I would argue that whatever reasoning was used to justify the original choice is as wrong today as it was back then. At any rate, that's something to follow up separately. REVISION DETAIL https://reviews.freebsd.org/D5872 EMAIL PREFERENCES https://reviews.freebsd.org/settings/panel/emailpreferences/ To: sepherosa_gmail.com, network, glebius, adrian, delphij, decui_microsoft.com, honzhan_microsoft.com, howard0su_gmail.com, freebsd-net-list, transport, jtl, hiren, lstewart Cc: gnn, mike-karels.net, jtl