[ntp:questions] Re: SHM refclock not being selected

John Ackermann N8UR jra at febo.com
Sun Mar 13 14:25:58 UTC 2005


David Schwartz wrote:

>  
>
>>Should I be using the "prefer" keyword to force selection of the SHM 
>>clock?  Or is there some other trick I should be playing with this 
>>configuration?
>>    
>>
>
>    Can you post your configuration? I'm wondering if perhaps you have some 
>'restrict default' lines without the appropriate override. It may help to 
>add this:
>
>restrict 127.0.0.0 mask 255.0.0.0
>
>  
>
Here's my configuration file, with logging stuff, etc., trimmed for brevity:

    # /etc/ntp.conf, configuration for ntpd

    # Z3801A
    server 127.127.26.0 ttl 1
    fudge 127.127.26.0 time1 -0.967
    fudge 127.127.26.0 refid GPS

    # PPS via linux_shm_clock
    server 127.127.28.0
    fudge 127.127.28.0 refid PPS

    server tock.febo.com
    server time-c.timefreq.bldrdoc.gov
    server ntp1.usno.navy.mil
    server ntp2.usno.navy.mil

That's it...

>>By the way -- I was getting absolutely horrendous, unusable time from this 
>>machine until I recompiled the 2.6.9 kernel with HZ=100, and selected 
>>"clock=pit" at boot time (not sure which of the two changes is making the 
>>most significant impact; I wasn't in a position to experiment through 
>>multiple reboots).
>>    
>>
>
>    Now that's strange. Does this machine have one CPU or more than one? 
>What type?
>  
>
It's an Athlon 2200 or thereabouts.  When I was running a 2.4 kernel, I 
had no problems but the change to 2.6 (necessitated by some other 
software that is the machine's primary reason for being) really screwed 
things up.

John




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