From mboxrd@z Thu Jan 1 00:00:00 1970 From: "David S. Miller" Subject: Re: Controlling TCP window size Date: Tue, 16 May 2006 16:01:57 -0700 (PDT) Message-ID: <20060516.160157.78923603.davem@davemloft.net> References: <4469B251.3050901@andyfurniss.entadsl.com> <446A19C7.1000302@psc.edu> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: lists@andyfurniss.entadsl.com, netdev@vger.kernel.org Return-path: Received: from dsl027-180-168.sfo1.dsl.speakeasy.net ([216.27.180.168]:53389 "EHLO sunset.davemloft.net") by vger.kernel.org with ESMTP id S932250AbWEPXBt (ORCPT ); Tue, 16 May 2006 19:01:49 -0400 To: jheffner@psc.edu In-Reply-To: <446A19C7.1000302@psc.edu> Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org From: John Heffner Date: Tue, 16 May 2006 14:28:23 -0400 > The problem really is that the window_clamp variable is overloaded. > It's used as a kind of cache for rcvbuf -> window conversion, but also > as a user-settable bound in window size. On examination, it looks like > this is also broken (in that window size won't increase) if a user does > a setsockopt(SO_RCVBUF). Can we make window_clamp a true clamp? Then > we can get rid of the hack of raising it in tcp_rcv_space_adjust(). I > can cook up a patch if interested. The clamp gets moved along also to handle dynamic receive window sizing. To be honest, a window clamp doesn't have clear semantics in the presence of dynamic window sizing. Anyways, I'd like to see your patch. It might make rcvbuf --> window conversions a bit more expensive, but we'll see.