[ntp:questions] Odd (mis)behavior when reference clock fails

Unruh unruh-spam at physics.ubc.ca
Fri Sep 26 00:08:15 UTC 2008


hal-usenet at ip-64-139-1-69.sjc.megapath.net (Hal Murray) writes:


>>Why would you poll a UPS as fast as you can? This sounds like the old
>>joke-- Doctor I have a real headache-- What do you do?-- Before it hurts I
>>bash my head against a brick wall.

>It seemed like a reasonable idea at the time.  I'm using it to monitor
>the line voltage.  You send it a command.  It tells you the min input
>voltage since the last time you asked.  The faster I ask the better
>time resolution I get on the duration of glitches.

Does it really make sense to get microsecond resolution on the glitches. 

Try puttin in a microsleep into your routine to see if that solves the
clock problem. It is possible that the reading of the ups is done via some
sort of badly written interrupt routine which holds open the interrupts too
long. It is however a bit weird I will admit. 




>>It sounds like you are losing timer interrupts.

>Thanks for the suggestion.  It's a 1 GHz VIA C7 system.  It was running
>at 250 Hz.  I just switched to 100.  No change.







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