On 22.03.2012 09:33, David Cure wrote:
Le Thu, Mar 22, 2012 at 09:53:45AM +0200, Gleb Natapov ecrivait :
All true. I asked to try -hypervisor only to verify where we loose
performance. Since you get good result with it frequent access to PM
timer is probably the reason. I do not recommend using -hypervisor for
production!
so if I leave cpu as previous (not defined) and only disable
hpet and use 1 vcpu, it's ok for production ?
this is ok, but windows will use pm timer so you will have bad performance.
Is there a workaround for this PM access ?
there exists old patches from 2010 for in-kernel pmtimer. they work, but
only
partly. problem here is windows enables the pmtimer overflow interrupt
which this
patch did not address (amongst other things). i simply ignored it and
windows ran
nevertheless. but i would not do this in production because i do not
know which side
effects it might have.
there are to possible solutions:
a) a real in-kernel pmtimer implementation (which does also help other
systems not only windows)
b) hyper-v support in-kernel at least partly (for the timing stuff).
this is being worked on by Vadim.
Peter
David.
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