From owner-freebsd-current Thu Sep 25 17:07:55 1997 Return-Path: Received: (from root@localhost) by hub.freebsd.org (8.8.7/8.8.7) id RAA23761 for current-outgoing; Thu, 25 Sep 1997 17:07:55 -0700 (PDT) Received: from pluto.plutotech.com (root@mail.plutotech.com [206.168.67.137]) by hub.freebsd.org (8.8.7/8.8.7) with ESMTP id RAA23751 for ; Thu, 25 Sep 1997 17:07:49 -0700 (PDT) Received: from narnia.plutotech.com (narnia.plutotech.com [206.168.67.130]) by pluto.plutotech.com (8.8.5/8.8.5) with ESMTP id SAA29559; Thu, 25 Sep 1997 18:07:36 -0600 (MDT) Message-Id: <199709260007.SAA29559@pluto.plutotech.com> X-Mailer: exmh version 2.0zeta 7/24/97 To: Terry Lambert cc: dg@root.com, ccsanady@bob.scl.ameslab.gov, current@FreeBSD.ORG Subject: Re: TCP timers (Was: Re: new timeout routines) In-reply-to: Your message of "Thu, 25 Sep 1997 22:56:55 -0000." <199709252256.PAA06930@usr04.primenet.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Date: Thu, 25 Sep 1997 18:07:23 -0600 From: "Justin T. Gibbs" Sender: owner-freebsd-current@FreeBSD.ORG X-Loop: FreeBSD.org Precedence: bulk >This will increase the load on the timer code with a lot of 20 tick >timers for a 100Hz softclock. No. There would be exactly one TCP timer for doing delayed acks in the queue at a given time. The TCP code would be performing it's own "one shot" timer management if you will. >I haven't seen a formal layout of the design Archie Cobb said he >discussed with Julian, so I can't comment on that, but it would be >a good idea to consider all angles before making such a significant >change to the networking code (one of BSD's shiny spots). Archie's design is similar to having a set of hierarchical timing wheels which would handle large loads of timers with varying lifespans and chances of expiration better than the single level wheel we have now. I think that this is a better approach than having an ordered/unordered list for each bucket. See the G.Varghese and A. Lauck paper I referenced yesturday: http://dworkin.wustl.edu/~varghese/PAPERS/twheel.ps.Z Which is the second paper the timeout.9 man page references. > Regards, > Terry Lambert > terry@lambert.org >--- >Any opinions in this posting are my own and not those of my present >or previous employers. > -- Justin T. Gibbs =========================================== FreeBSD: Turning PCs into workstations ===========================================