From owner-freebsd-hackers Fri Dec 28 10:18:28 2001 Delivered-To: freebsd-hackers@freebsd.org Received: from iguana.icir.org (iguana.icir.org [192.150.187.36]) by hub.freebsd.org (Postfix) with ESMTP id 0474337B428 for ; Fri, 28 Dec 2001 10:18:23 -0800 (PST) Received: (from rizzo@localhost) by iguana.icir.org (8.11.3/8.11.1) id fBSIIKV09042; Fri, 28 Dec 2001 10:18:20 -0800 (PST) (envelope-from rizzo) Date: Fri, 28 Dec 2001 10:18:20 -0800 From: Luigi Rizzo To: sridharv@ufl.edu Cc: hackers@FreeBSD.ORG Subject: Re: IP queue question Message-ID: <20011228101820.A9030@iguana.icir.org> References: <200112280640.BAA01182@anansi.vpha.health.ufl.edu> <20011227224726.A3662@iguana.icir.org> <200112281655.LAA19207@anansi.vpha.health.ufl.edu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200112281655.LAA19207@anansi.vpha.health.ufl.edu> User-Agent: Mutt/1.3.23i Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG On Fri, Dec 28, 2001 at 11:55:36AM -0500, sridharv@ufl.edu wrote: > is there any specific advantage in using > device_polling method? does is give sth other than > fairness? or is the multiple queue a 100% a;ternative? > can u tell me a bit more about inline processing? or > pointers to text would also do sorry, i forgot... have a look at http://www.iet.unipi.it/~luigi/polling/ cheers luigi > cheers > s > Quoting Luigi Rizzo : > > > Hi, > > FreeBSD uses a single queue, but as long as you make > sure that you > > do not fill the queue with packets coming from a > single interface, > > you can still give some fairness to the system. > Recent "DEVICE_POLLING" > > code in -current (hopefully going into -stable at > some point) does > > exactly this -- an alternative way, which is not > terribly hard to > > implement, could be to put packets from each > interface into a > > separate queue as Comer suggests, and then going > round-robin on > > these queues upon the software interrupt. > > > > As for the soft interrupt going away soon, this > won't happen, there > > are pros and cons for using delayed processing so > the goal is to > > augment the mechanism with inline processing, not > replace it. > > > > cheers > > luigi > > > > On Fri, Dec 28, 2001 at 01:40:00AM -0500, > sridharv@ufl.edu wrote: > > > I was reading TCP/IP Vol 2 by douglas comer. In > that > > > he has one queue for each interface from which the > IP > > > layer processes the incoming datagrams. He has used > > > round-robin for fairness. I checked up the BSD code > > > and it seems to use only one queue 'ipintrq'. The > > > ethernet driver places the mbuf in this queue for > an > > > IP payload. Comer has also asked a review question > > > pertaining to the disadvantage of having a single > > > queue ( which i presume inhibits fair scheduling > and > > > stuff) > > > Have I interpreted the code correctly? Y is this > so in > > > BSD? > > > Also when I took a look at FreeBSD ipinput code the > > > ipintr function which handles the software > interrupt > > > had a comment which said " to go away sometime > soon" . > > > Why and what is the alternative? > > > > > > The fastest way to change is to laugh at your own > > > folly - Who moved my cheese > > > > > > To Unsubscribe: send mail to majordomo@FreeBSD.org > > > with "unsubscribe freebsd-hackers" in the body of > the message > > > > > > The fastest way to change is to laugh at your own > folly - Who moved my cheese > > To Unsubscribe: send mail to majordomo@FreeBSD.org > with "unsubscribe freebsd-hackers" in the body of the message To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message