From owner-freebsd-arch@FreeBSD.ORG Fri Oct 22 15:55:47 2004 Return-Path: Delivered-To: freebsd-arch@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id CAA5C16A4CE for ; Fri, 22 Oct 2004 15:55:47 +0000 (GMT) Received: from c00l3r.networx.ch (c00l3r.networx.ch [62.48.2.2]) by mx1.FreeBSD.org (Postfix) with ESMTP id 0F23743D1F for ; Fri, 22 Oct 2004 15:55:47 +0000 (GMT) (envelope-from andre@freebsd.org) Received: (qmail 87684 invoked from network); 22 Oct 2004 15:54:12 -0000 Received: from unknown (HELO freebsd.org) ([62.48.0.53]) (envelope-sender ) by c00l3r.networx.ch (qmail-ldap-1.03) with SMTP for ; 22 Oct 2004 15:54:12 -0000 Message-ID: <41792D81.C030A26F@freebsd.org> Date: Fri, 22 Oct 2004 17:55:45 +0200 From: Andre Oppermann X-Mailer: Mozilla 4.8 [en] (Windows NT 5.0; U) X-Accept-Language: en MIME-Version: 1.0 To: Brian Fundakowski Feldman References: <4177C8AD.6060706@freebsd.org> <71C3A1EA-238F-11D9-9171-000A95C705DC@chittenden.org> <41780672.6AAC705F@freebsd.org> <417923BF.661D2A6D@freebsd.org> <20041022154517.GN1072@green.homeunix.org> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit cc: freebsd-arch@freebsd.org Subject: Re: Removing T/TCP and replacing it with something simpler X-BeenThere: freebsd-arch@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Discussion related to FreeBSD architecture List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 22 Oct 2004 15:55:47 -0000 Brian Fundakowski Feldman wrote: > > On Fri, Oct 22, 2004 at 05:14:07PM +0200, Andre Oppermann wrote: > > None of it. Neither NOPUSH nor CORK have any security implications. > > Those are only with the specification of T/TCP. Blocking the data > > is independend of 3WSH. Normally you have Nagle enabled (default) > > and when you don't fill an entire packet worth of data it will wait > > up to 200ms to send the packet in anticipation of more data from the > > socket. This screws the responsiveness of your connection. The first > > solution is to turn off Nagle (with TCP_NODELAY) but now you get a > > packet for every single write() you do. Fine for telnet and ssh but > > not the right thing for a database server. There you don't want the > > delay but at the same time you want several successive write()s that > > will go in one packet on the wire. Here NOPUSH and CORK come into > > play. > > Why is just tuning the delay a bad solution? If you tune it too low it ain't useful anymore (doesn't gather distant writes together) and too many timers too often. -- Andre