[ntp:questions] Slow convergence of NTP with GPS/PPS

Hal Murray hal-usenet at ip-64-139-1-69.sjc.megapath.net
Tue Oct 21 21:58:23 UTC 2008

>> The driftfile also sometimes seems to do more harm than good - especially
>> after a reboot.
>Some kernels do a calibration of clock against RTC clock. This will make
>driftfile misleading.

There is a bug in the Linux calibration routine for the TSC mode
clock.  It doesn't get a consistent answer.  I hacked the code
to loop and print the answer.  It was a splatter.  None were far
off unless you are a time keeping geek.  It's easy to see the
different drift results and startup transients are "interesting".

clocksource=acpi_pm on the boot command line might help.

These are my opinions, not necessarily my employer's.  I hate spam.

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