From owner-freebsd-stable@FreeBSD.ORG Wed Dec 19 17:04:34 2007 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id D62B716A417; Wed, 19 Dec 2007 17:04:34 +0000 (UTC) (envelope-from dg@dglawrence.com) Received: from dglawrence.com (static-72-90-113-2.ptldor.fios.verizon.net [72.90.113.2]) by mx1.freebsd.org (Postfix) with ESMTP id B4B1213C447; Wed, 19 Dec 2007 17:04:34 +0000 (UTC) (envelope-from dg@dglawrence.com) Received: from tnn.dglawrence.com (localhost [127.0.0.1]) by dglawrence.com (8.14.1/8.14.1) with ESMTP id lBJH4Yt0046644; Wed, 19 Dec 2007 09:04:34 -0800 (PST) (envelope-from dg@dglawrence.com) Received: (from dg@localhost) by tnn.dglawrence.com (8.14.1/8.14.1/Submit) id lBJH4YCu046643; Wed, 19 Dec 2007 09:04:34 -0800 (PST) (envelope-from dg@dglawrence.com) X-Authentication-Warning: tnn.dglawrence.com: dg set sender to dg@dglawrence.com using -f Date: Wed, 19 Dec 2007 09:04:34 -0800 From: David G Lawrence To: Bruce Evans Message-ID: <20071219170434.GG25053@tnn.dglawrence.com> References: <20071218170133.X32807@delplex.bde.org> <47676E96.4030708@samsco.org> <20071218233644.U756@besplex.bde.org> <20071218141742.GS25053@tnn.dglawrence.com> <20071219022102.I34422@delplex.bde.org> <20071218165732.GV25053@tnn.dglawrence.com> <20071218181023.GW25053@tnn.dglawrence.com> <20071219235444.K928@besplex.bde.org> <20071219151926.GA25053@tnn.dglawrence.com> <20071220032223.V38101@delplex.bde.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20071220032223.V38101@delplex.bde.org> X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-3.0 (dglawrence.com [127.0.0.1]); Wed, 19 Dec 2007 09:04:34 -0800 (PST) Cc: freebsd-net@freebsd.org, freebsd-stable@freebsd.org Subject: Re: Packet loss every 30.999 seconds X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 19 Dec 2007 17:04:34 -0000 > > In any case, it appears that my patch is a no-op, at least for the > >problem I was trying to solve. This has me confused, however, because at > >one point the problem was mitigated with it. The patch has gone through > >several iterations, however, and it could be that it was made to the top > >of the loop, before any of the checks, in a previous version. Hmmm. > > The patch should work fine. IIRC, it yields voluntarily so that other > things can run. I committed a similar hack for uiomove(). It was It patches the bottom of the loop, which is only reached if the vnode is dirty. So it will only help if there are thousands of dirty vnodes. While that condition can certainly happen, it isn't the case that I'm particularly interested in. > CPUs, everything except interrupts has to wait for these syscalls. Now > the main problem is to figure out why PREEMPTION doesn't work. I'm > not working on this directly since I'm running ~5.2 where nearly-full > kernel preemption doesn't work due to Giant locking. I don't understand how PREEMPTION is supposed to work (I mean to any significant detail), so I can't really comment on that. -DG David G. Lawrence President Download Technologies, Inc. - http://www.downloadtech.com - (866) 399 8500 The FreeBSD Project - http://www.freebsd.org Pave the road of life with opportunities.