From owner-freebsd-current Wed Dec 19 16: 1:41 2001 Delivered-To: freebsd-current@freebsd.org Received: from apollo.backplane.com (apollo.backplane.com [216.240.41.2]) by hub.freebsd.org (Postfix) with ESMTP id B212A37B417 for ; Wed, 19 Dec 2001 16:01:39 -0800 (PST) Received: (from dillon@localhost) by apollo.backplane.com (8.11.6/8.9.1) id fBK01c721879; Wed, 19 Dec 2001 16:01:38 -0800 (PST) (envelope-from dillon) Date: Wed, 19 Dec 2001 16:01:38 -0800 (PST) From: Matthew Dillon Message-Id: <200112200001.fBK01c721879@apollo.backplane.com> To: Doug White Cc: Subject: Re: Seeing a lot of 'microuptime() went backwards' messages during heavy disk I/O References: Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG :This has been asked on just about every FreeBSD list since the printf was :added. Use the archives, man! :) : :This is when you have a device generating too much interrupt latency -- :enough to stall the RTC. Usually the offender is video cards, but in this :case it could be your IDE controller. This is on a SCSI machine, but I get your drift. :The usual fix is to try changing timecounters; sysctl :kern.timecounter.hardware tells you what you're currently using. If :you're on CURRENT, it's probably using ACPI. If you want to override it :back to TSC, put 'hint.acpi_timer.0.disabled="1"' in your :/boot/device.hints. Also try compiling with or without apm since this :influences the timecounter as well (although if you're on SMP you might be :stuck with the i8254). : :phk can clarify. :) : :Doug White | FreeBSD: The Power to Serve I would prefer that it figure out the correct time counter itself rather then plague us with fraggin microuptime messages for the last N years :-( -Matt Matthew Dillon To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message