Comment 345 for bug 993187

Chowno, issuing the following command will tell you which clock source is being used. The first line is the available clock sources, and the second line is the currently active clock source:

cat /sys/devices/system/clocksource/clocksource0/*

On my system, this returns:
tsc hpet acpi_pm
hpet

I had to switch to hpet since the tsc timing source is inaccurate on my system and caused system instability.