Wierd time changes

[Mark Ovens]

Mark Ovens wrote:
> Denis R. wrote:
>> Hi Mark and list members,
>> 
>> I am experiencing the same problem on my dual PII-450 SP700 Compaq Pro
>> workstation. After poking around on Google, it is pointing to the FreeBSD
>> and a i8254 programmable interupt timer. In my case the time is lagging
>> behind 10 times! What does your:
>> #time sleep 10
>> show?
> 
> redshift# time sleep 10
> 0.000u 0.001s 0:10.00 0.0%      0+0k 0+0io 0pf+0w
> redshift#
> 
> The clock maintains the correct time whilst FreeBSD is running, it just 
> suddenly changes, at least somewhere "inside" FreeBSD, during shutdown 
> but doesn't screw the system clock until the next reboot, and even after 
> that it maintains consistent, but incorrect, time; i.e. it doesn't gain 
> or lose at a steady rate.
> 

To follow up:

Based on your comments Denis, I tried the 
kern.timecounter.hardware=i8254 workround - didn't work. I also spun a 
UP kernel - that didn't work either. Confirms that it is something 
specific to my machine (or the Asus A7M266-D m/b and BIOS).

Where does FreeBSD store the corrupted time across reboots though and, 
more importantly, why?

I don't know where to go from here. I do have an old IDE drive lying 
around so I guess I could put 4.9 on that and see if the problem exists 
there as well.

Regards,

Mark

> Regards,
> 
> Mark
> 
>> It takes 25 seconds on my SMP workstation to execute a 10 second delay. I
>> have modified the /etc/sysctl.conf and added:
>> kern.timecounter.hardware=i8254
>> 
>> ntpd couldn't cope with this problem on my server. I have to run ntpdate
>> every 10 minutes to set the time to an approximately accepted value :-(.
>> 
>> There used to be a problem on older releases of FreeBSD (4.2 and up)
>> related to a SMP kernel and clock. Someone posted a hack fix of the:
>> usr/src/sys/i386/isa/clock.c file. But apparently it has been fixed in
>> newer releases and does not get mentioned in 5.x.
>> 
>> The most common fix I've heard from people is to recompile the kernel and
>> exclude the SMP support. But if this is the case, I'd be switching to a
>> mono CPU support of OpenBSD to run it. One of the reasons I like FreeBSD
>> is its SMP support.
>> 
>> People, any ideas?
>> 
>> dmesg part:
>> MPTable: <COMPAQ   Workstation >
>> Timecounter "i8254" frequency 1193182 Hz quality 0
>> uname -a:
>> FreeBSD 5.2-RELEASE FreeBSD 5.2-RELEASE #0: Sun Jan 11 04:21:45 GMT 2004  
>>   root at wv1u.btc.adaptec.com:/usr/obj/usr/src/sys/GENERIC  i386
>> 
>> Thanks and regards!
>> Denis
>> 
>> 
>>>>>>>>>>>>>>>>>
>> I'm completely baffled by this one. When FreeBSD shuts down/reboots it
>> changes the system clock. It *always* sets the hours to 20 and changes
>> the minutes and seconds (but I haven't worked out a pattern for that),
>> but the date stays the same (see /var/log/messages below) although I
>> once saw it keep the time and date correct, but set the year back *four*
>> years(!) but that was when the correct time was 22:mm:ss.
>> 
>> 
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>> 
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