Messages in this thread | | | Subject | Re: + stupid-hack-to-make-mainline-build.patch added to -mm tree | From | Rusty Russell <> | Date | Thu, 08 Mar 2007 21:26:54 +1100 |
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On Thu, 2007-03-08 at 09:01 +0100, Ingo Molnar wrote: > * Jeremy Fitzhardinge <jeremy@goop.org> wrote: > > > > Your implementation is almost the perfect prototype, if you move the > > > 128 bit hackery into the hypervisor and hide it away from the kernel > > > :) > > > > The point is to use the tsc to avoid making any hypercalls, so dealing > > with the tsc->ns conversion has to happen on the guest side somehow. > > you are obsessed with avoiding a hypercall, but why? Granted it's slow > especially on things like SVN/VMX, but it's not fundamentally slow. We > definitely do not want to design our whole APIs and abstractions around > the temporary notion that 'hypercalls are slow'. I'd expect hypercalls > to be put into silicon just as much as SYSENTER was put into silicon.
Indeed, I expect them to fall somewhere between system calls and context switches. Perhaps not slow, but definitely worth minimising.
> Anyway, in terms of guest time code, a /big/ amount of design junk can > be avoided by not trying to do sillynesses like 'virtual time'. The TSC > is awfully unreliable.
You mean stolen time?
I find this whole discussion really irritating, to be honest. I just want Thomas to implement the timer code for lguest, because that code scares me...
I look forward to your patch 8) Rusty.
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