Fix clocksource for ntp
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One one of my machines I had to manipulate the system date/time to ensure that PDFs of different versions of a TTF font (produced by 'fret' which includes the date and time in the heading) matched. That caused me to looked at my syslog, and I discovered that not everything was rosy.
I saw several messages like
frequency error 1726 PPM exceeds tolerance 500 PPM
although these had not previously been apparent, and something in the current kernel (after a lot of software suspends and wakens) maybe dropped the ball. However, the box was no longer synchronising.
This is apparently fixable by:
- Check the available clock sources in cat /sys/devices/system/clocksource/clocksource0/available_clocksource
- The default is now tsc, it used (years ago!) to be acpi_pm. Assuming
acpi_pm is available, echo that to /sys/devices/system/clocksource/clocksource0/current_clocksource
- If things improve, add that as a boot option in grub, i.e.
At the moment I've been running with acpi_pm for a bit over a day, but I haven't rebooted to force it from grub.