-no-hpet -rtc-td-hack
-rtc-td-hack use it to fix time drift in Windows ACPI HAL
-no-hpet
Disable HPET support.
-rtc [base=utc|localtime|date][,clock=host|vm][,driftfix=none|slew]
Specify base as utc or localtime to let the RTC start at the current UTC or local time, respectively. localtime is required for correct date in MS-DOS or Windows. To start at a specific point in time, provide date in the format 2006-06-17T16:01:21 or 2006-06-17. The default base is UTC.
By default the RTC is driven by the host system time. This allows to use the RTC as accurate reference clock inside the guest, specifically if the host time is smoothly following an accurate external reference clock, e.g. via NTP. If you want to isolate the guest time from the host, even prevent it from progressing during suspension, you can set clock to vm instead.
Enable driftfix (i386 targets only) if you experience time drift problems, specifically with Windows' ACPI HAL. This option will try to figure out how many timer interrupts were not processed by the Windows guest and will re-inject them.
kvm-clock
Hangs soon after boot.
hpet
Stable O/S, clock skew between -0.039 and 0.068 msec (0.107ms band).
acpi_pm
Stable O/S, clock skew between 0.002 and 0.071 msec (0.069ms band).
jiffies
Stable O/S, clock skew between 0.426 and 1.312 msec (0.886ms band).
tsc
Stable O/S, clock skew between 0.003 and 0.354 msec (0.351 band).
More worrying is that it was growing larger and larger, whereas the other clocksources were sort of oscillating between the two extremes.
