From owner-freebsd-hackers@FreeBSD.ORG Mon Jun 2 13:02:01 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 099D937B404; Mon, 2 Jun 2003 13:02:01 -0700 (PDT) Received: from perrin.int.nxad.com (internal.ext.nxad.com [69.1.70.251]) by mx1.FreeBSD.org (Postfix) with ESMTP id 392C943FA3; Mon, 2 Jun 2003 13:02:00 -0700 (PDT) (envelope-from sean@nxad.com) Received: by perrin.int.nxad.com (Postfix, from userid 1001) id 065F32105A; Mon, 2 Jun 2003 13:01:59 -0700 (PDT) Date: Mon, 2 Jun 2003 13:01:58 -0700 From: Sean Chittenden To: Julian Elischer Message-ID: <20030602200158.GH65470@perrin.int.nxad.com> References: <20030530133302.A48390@FreeBSD.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-PGP-Key: finger seanc@FreeBSD.org X-PGP-Fingerprint: 3849 3760 1AFE 7B17 11A0 83A6 DD99 E31F BC84 B341 X-Web-Homepage: http://sean.chittenden.org/ User-Agent: Mutt/1.5.4i cc: Juli Mallett cc: hackers@freebsd.org Subject: Re: Network stack cloning / virtualization patches X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 02 Jun 2003 20:02:01 -0000 > > Has anyone looked at making the patch work with CURRENT? Does > > this do anything to degrade performance of UP systems with no (0?) > > virtualised images running? > > I have been running tests between two machines with this patch > installed. There is a "per packet" overhead increase of about 1%. > there is no overhead increase in the per-byte overhead.. in ther > words, sending 1 byte packets gets about a 1% decrease in throughput > but sending 8k chunks has almost no overhead increase.. > > Both my machines end up maxing out the 100Mb ethernet between them > before they see any speed difference at high packet sizes. 1% per packet seems a bit high... where is the overhead coming from? Seems as though there should be less overhead and that lookup of the necessary components for each vimage could be found with a hash... I looked through the patch and couldn't see any places that screamed optimization. Is the overhead really just from copying the data of the vimage around? > > Does it make the locking situation much worse? Can it be stripped > > down to minimal, clean, well-architected diffs to accomplish a > > centralised goal, rather than a "Network+goodies, random subsystem > > overhaul"? > > It is unlikely that the patches could be made in smaller orthogonal > patches. Its kind of "all or nothing".. Either everything is global > or it is in a structure (per VM). *nods* Hrm, it would appear so. > > If this is your priority patch, hunting down someone with serious > > network\ stack-fu to review the diff, and whatnot, would probably > > be a good investment of your time in that regard. > > I'll bepresenting Marco's paper at USENIX on the (ummm 12th I > think). His baby is due then so he can't make it.. (whereas mine > arrived today so I'll be looking for an excuse to be away from the > house for 2 days ;-) :) Congrats (again!)! Julian, am I safe in assuming that you have an interest in this work? If not, I may setup a p4 branch to work with and to merge these bits into -CURRENT if no one else is interested. -sc -- Sean Chittenden