From owner-freebsd-hackers@FreeBSD.ORG Thu Sep 18 11:23:26 2003 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id A25FE16A4B3 for ; Thu, 18 Sep 2003 11:23:26 -0700 (PDT) Received: from venom.ai.net (venom.ai.net [205.134.161.156]) by mx1.FreeBSD.org (Postfix) with ESMTP id C593243FBD for ; Thu, 18 Sep 2003 11:23:25 -0700 (PDT) (envelope-from deepak@ai.net) Received: from blood (pool-68-163-66-91.res.east.verizon.net [68.163.66.91]) by venom.ai.net (8.12.6/8.12.8) with SMTP id h8IIIbJD082288; Thu, 18 Sep 2003 14:18:38 -0400 (EDT) (envelope-from deepak@ai.net) From: "Deepak Jain" To: "Terry Lambert" Date: Thu, 18 Sep 2003 14:22:36 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook IMO, Build 9.0.2416 (9.0.2911.0) X-MimeOLE: Produced By Microsoft MimeOLE V5.50.4927.1200 In-Reply-To: <3F6975BD.14CD05EE@mindspring.com> Importance: Normal cc: "freebsd-hackers@FreeBSD. ORG" Subject: RE: TCP information X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list Reply-To: deepak@ai.net List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 18 Sep 2003 18:23:26 -0000 > These types of statistics aren't kept. > > Generally, they are used only by network researchers, who hack > their stacks to get them. > > They usually do not make it into commercial product distributions > for performance reasons, and because every byte added to a tcpcb > structure is one byte less that can be used for something else. > In practice, adding 134 bytes of statistics to a tcpcb would > double its size and halve the number of simultaneous connections > you would be able to support with the same amount of RAM in a > given machine (as one example), if all of that memory had to > come out of the same space, all other things being equal. If the tcpcb struct were expanded/changed and the various increments were added in the appropriate packet pushing code, this would work right? Is there something non-obvious that one would need to worry about to undertake such a project? Thanks, Deepak Jain AiNET