Re: [PATCH] Skip tsc synchronization checks if CONSTANT_TSC bit is set.

[Andi Kleen]

> Not really, there are problems with the pm timer too, the one about
> missing the counter wrap and time dropping in chunks of 4 seconds.
> Tried to explain it over here, http://lkml.org/lkml/2008/10/22/525

Well then pit. Or are you saying time is always broken on VMware & Linux?

> So TSC is the ideal clocksource from performance and correctness point
> of view for VMware. 

But you don't seem to emulate it "ideal"ly otherwise you wouldn't
need all these hacks you're adding? 

I think you should either implement a TSC that matches what
real hardware does (including CPUID semantics) or implement
a real vmware PV timer and just say it's PV and not fully virtualized. 
But doesn't the vmware paravirt ops have that already anyways?

But I personally think it wouldn't really scale to add detection for 
more and more "nearly PV" hypervisors to the standard native kernel.

-Andi
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/