From owner-freebsd-hackers@FreeBSD.ORG Fri May 9 07:28:46 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 292A837B404 for ; Fri, 9 May 2003 07:28:46 -0700 (PDT) Received: from transport.cksoft.de (transport.cksoft.de [62.111.66.27]) by mx1.FreeBSD.org (Postfix) with ESMTP id 7285443FAF for ; Fri, 9 May 2003 07:28:42 -0700 (PDT) (envelope-from bzeeb-lists@zabbadoz.net) Received: from localhost (localhost [127.0.0.1]) by transport.cksoft.de (Postfix) with ESMTP id 885841FFBBF; Fri, 9 May 2003 16:28:40 +0200 (CEST) Received: by transport.cksoft.de (Postfix, from userid 66) id 94AB31FFBC7; Fri, 9 May 2003 16:28:39 +0200 (CEST) Received: by mail.int.zabbadoz.net (Postfix, from userid 1060) id 9CFAA1537D; Fri, 9 May 2003 14:20:03 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by mail.int.zabbadoz.net (Postfix) with ESMTP id 928AE15350; Fri, 9 May 2003 14:20:03 +0000 (UTC) Date: Fri, 9 May 2003 14:20:03 +0000 (UTC) From: "Bjoern A. Zeeb" X-X-Sender: bz@e0-0.zab2.int.zabbadoz.net To: Junwen Lai In-Reply-To: Message-ID: References: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-Virus-Scanned: by AMaViS snapshot-20020300 cc: freebsd-hackers@freebsd.org Subject: Re: microuptime() went backwards. 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: Fri, 09 May 2003 14:28:46 -0000 On Thu, 8 May 2003, Junwen Lai wrote: > > May 8 20:01:51 FeliX /kernel: microuptime() went backwards (39515.922679 -> 15.898650) > this happens when you change the system time, either by running "time" > explicitly or using something like ntptime. Not a big deal, just ignore > it. I still can reproduce it by doing heavy disk IO, eg. nightly backups to my amanda server. This happens w/ and w/o ntpd running (external clock connected). Suggestions from other PRs with apm etc. didn't help. Someone said it's because of the VIA chipset but changing the motherboard is not a solution. The time I first saw it was the first time of greater moves around filesystems after I turned softupdates on. Further more - before I had the external clock - I had times the next morning in the range from yesterday eve to the day high noon. I still sometimes have probs with nightly periodic scripts running twice :( At the moment this is a 4.7-STABLE box. I will update to 5-CURRENT once I find the time and see. I haven't checked the peace of code around thos messages there nbut at least someone removed or changed the 'microuptime() went backwards' log messages from what I could see. One last note: the problem here is that when logging kern.* to syslog the microuptime() went backwards warnings may produce a huge amount of log data (up to 50MB) and thus will also add some more disc IO so this may make the situation even worse. I didn't rebuild may latest kernels with some rate limiting for those logs included. I may help to exclude the '(39515.922679 -> 15.898650)' from logging so syslog can aggregate the messages. For more information you may check the ml archives and search (closed) PRs on the topic. -- Greetings Bjoern A. Zeeb bzeeb at Zabbadoz dot NeT 56 69 73 69 74 http://www.zabbadoz.net/