On Wed, 12 Sep 2012, Matthew Ogilvie wrote: > Also, how big of a concern is a very rare gained or lost IRQ0 > actually? Under normal conditions, I would expect this to at most > cause a one time clock drift in the guest OS of a fraction of > a second. If that only happens when rebooting or migrating the > guest...
It depends on how you define "very rare". Once per month or probably even per day is probably acceptable although you'll see a disruption in the system clock. This is still likely unwanted if the system is used as a clock reference and not just wants to keep its clock right for own purposes. Anything more frequent and NTP does care very much; an accurate system clock is important in many uses, starting from basic ones such as where timestamps of files exported over NFS are concerned. Speaking of real hw -- I don't know whether that really matters for emulated systems. Thanks for looking into the 8254 PIT in details. Maciej
