From owner-freebsd-hackers Sun Dec 2 11:36:43 2001 Delivered-To: freebsd-hackers@freebsd.org Received: from technokratis.com (modemcable099.144-201-24.mtl.mc.videotron.ca [24.201.144.99]) by hub.freebsd.org (Postfix) with ESMTP id 13C0037B419 for ; Sun, 2 Dec 2001 11:36:09 -0800 (PST) Received: (from bmilekic@localhost) by technokratis.com (8.11.4/8.11.3) id fB2JjlK58748; Sun, 2 Dec 2001 14:45:47 -0500 (EST) (envelope-from bmilekic) Date: Sun, 2 Dec 2001 14:45:47 -0500 From: Bosko Milekic To: Matthew Dillon Cc: Richard Sharpe , freebsd-hackers@FreeBSD.ORG Subject: Re: Patch #3 (TCP / Linux / Performance) Message-ID: <20011202144547.A58695@technokratis.com> References: <15364.38174.938500.946169@caddis.yogotech.com> <20011128104629.A43642@walton.maths.tcd.ie> <5.1.0.14.1.20011130181236.00a80160@postamt1.charite.de> <200111302047.fAUKlT811090@apollo.backplane.com> <200111302130.fAULUU324648@apollo.backplane.com> <3C08CF9D.2030109@ns.aus.com> <200112012138.fB1LcG837063@apollo.backplane.com> <200112020810.fB28Arr77757@apollo.backplane.com> <3C0A3204.3010009@ns.aus.com> <200112021918.fB2JIg592414@apollo.backplane.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5i In-Reply-To: <200112021918.fB2JIg592414@apollo.backplane.com>; from dillon@apollo.backplane.com on Sun, Dec 02, 2001 at 11:18:42AM -0800 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 Sun, Dec 02, 2001 at 11:18:42AM -0800, Matthew Dillon wrote: [...] > :Does the FreeBSD tcp stack do zero copy (page flip the data to > :userspace)? In the localhost case, it seems like there are two copies > :to/from userspace there. > : > :-- > :Richard Sharpe, rsharpe@ns.aus.com, LPIC-1 > > There are zero-copy patches floating around but I haven't looked at > them to determine how messy they might be. http://people.freebsd.org/~ken/zero_copy/ The main issues with the patch are, afaics: 1. It's fairly large and difficult to maintain, especially in light of the large amount of SMPng-related changes. 2. The receive code only works with certain network cards. [This is expected]. The performance may also vary based on the behavior of the application. > -Matt > Matthew Dillon > -- Bosko Milekic bmilekic@technokratis.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message