RE: [Xen-devel] System time monotonicity

["Ian Pratt" <Ian.Pratt@xxxxxxxxxxxx>]

> > More likely a jittery chipset timer -- we've observed
less-than-ideal
> > stability from some chipset timers, which can throw us off a bit
when
> > independently sync'ing the TSCs (which each CPU does for its TSC
> > independently every couple of seconds).
> 
> And what about cross-VCPU monotonicity? It's called very frequently
and
> having to fake monotonicity via a single variable across all CPUs
would
> not be pleasant, unless I can think of something smarter...

One LOCK'ed cmpxchg is still a lot quicker than reading the pm_timer or
hpet...

Ian

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