From owner-freebsd-firewire@FreeBSD.ORG Wed Jan 27 05:10:15 2010 Return-Path: Delivered-To: freebsd-firewire@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id C7C25106566B; Wed, 27 Jan 2010 05:10:15 +0000 (UTC) (envelope-from freebsd@sopwith.solgatos.com) Received: from sopwith.solgatos.com (pool-98-108-131-15.ptldor.fios.verizon.net [98.108.131.15]) by mx1.freebsd.org (Postfix) with ESMTP id 5F7E28FC08; Wed, 27 Jan 2010 05:10:14 +0000 (UTC) Received: by sopwith.solgatos.com (Postfix, from userid 66) id 4ADCDB650; Tue, 26 Jan 2010 21:09:17 -0800 (PST) Received: from localhost by sopwith.solgatos.com (8.8.8/6.24) id SAA13144; Tue, 26 Jan 2010 18:56:30 GMT Message-Id: <201001261856.SAA13144@sopwith.solgatos.com> To: freebsd-firewire@freebsd.org, bug-followup@freebsd.org Date: Tue, 26 Jan 2010 10:56:30 PST From: Dieter Cc: Subject: Re: kern/118093: firewire bus reset hogs CPU, causing data to be lost X-BeenThere: freebsd-firewire@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Firewire support in FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 27 Jan 2010 05:10:15 -0000 > Looks like the kernel printf takes a *lot* of CPU, and > somehow locks out Ethernet. Looking through man pages working on an unrelated problem, I found: man timed says: Messages printed by the kernel on the system console occur with inter- rupts disabled. This means that the clock stops while they are printing. A machine with many disk or network hardware problems and consequent mes- sages cannot keep good time by itself. Each message typically causes the clock to lose a dozen milliseconds. If a kernel printf disables Ethernet interrupts for 12 milliseconds, that would create the problem.