Date: Fri, 9 May 2003 14:20:03 +0000 (UTC) From: "Bjoern A. Zeeb" <bzeeb-lists@lists.zabbadoz.net> To: Junwen Lai <lai@CS.Princeton.EDU> Cc: freebsd-hackers@freebsd.org Subject: Re: microuptime() went backwards. Message-ID: <Pine.BSF.4.53.0305091407090.650@e0-0.zab2.int.zabbadoz.net> In-Reply-To: <Pine.LNX.4.44.0305081610480.29779-100000@opus.CS.Princeton.EDU> References: <Pine.LNX.4.44.0305081610480.29779-100000@opus.CS.Princeton.EDU>
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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/
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