FBSD 5.5 and software timers

Michael Scheidell scheidell at secnap.net
Tue Jul 25 11:54:58 UTC 2006

> -----Original Message-----
> From: Peter Jeremy [mailto:peterjeremy at optushome.com.au] 
> Sent: Tuesday, July 25, 2006 4:00 AM
> To: Michael Scheidell
> Cc: freebsd-hackers at freebsd.org
> Subject: Re: FBSD 5.5 and software timers
> Basically, when you ask for a 200msec delay, the kernel 
> sleeps until an absolute time.  It looks like the handling of 
> absolute time sleeps across time steps was changed.  
> Unfortunately, both approaches are equally valid in different 
> circumstances.
I agree
> >It fails within 1 second of getting these types of log 
> entries: Jul 23 
> >15:03:42 audit18 ntpd[473]: time reset -2.497234 s Jul 23 16:03:56 
> >audit18 ntpd[473]: time reset +1.532401 s
> Rather than focussing on the changed sleep handling, I 
> suggest you concentrate on fixing your clock:  Your system 
> clock should not be stepping.
Except: 20 different machines.  Some IBM 300's with 2.0Ghz P4,s, 305 and
306's with 2.8P4, some DELL 750's and 850's with 2.8p4 with HTT enabled.

Even the 5.4 machines shows the bifurcating -1, +2, -2, +1 time resets,
but timers work more like I want them to.

> I presume the servers are all stable (ie not stepping) and 
> have a reasonably low delay.  If so, I suspect your ntpd PLL 
> has locked up. I've seen problems with some versions of ntpd 

20 different machines?

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