On Sat, Nov 08, 2008 at 10:36:20AM +0200, Gleb Natapov wrote:
I think the best ones are going to be intense host workload (and let's
see how much is needed before we start drifting badly) and high guest
frequencies with hosts that lack high resolution timers. I think with a
high resolution guest and no host overcommit, it should be very
difficult to produce drift regardless of what the guest is doing.
Later I'll try to generate load on a host an see how this affects
guest's time drift.
Just did that. Run qemu process bound to CPU 1 (taskset 1 qemu ...).
Run busy loop on the same CPU (taskset 1 bash -c "while true; do x='x'; done")
Run disk test utility as before inside a guest. After 40 minutes time
drift is almost 1 minute, but the drift was not gradual i.e I observed
gradual drift of 1 second per ~6 minutest, but sometimes there were jumps
of ~10 seconds.