Re: [Qemu-devel] [QEMU patch 2/2] kvm: allow configuration of tsc deadline timer advancement

[Radim Krčmář]

2014-12-10 18:55+0100, Paolo Bonzini:
> Well, my preferred choice would be automatic adjustment with a module
> parameter.  If we need manual tuning, per-CPU would be my choice, but
> automatic is nicer anyway. :)

I agree with Paolo, and think it would be better not to touch QEMU ...
it makes little sense to migrate this value and it is probably going to
be quite similar on every CPU, so a writeable module parameter is a
better starting point.  (We can always turn it into a nightmare later.)

If you measure the difference between the TSC you wanted and got on VM
entry, you can use it to automatically guess a delta for the next timer.
(That is IMO exactly what you would do with a manual tuning.
 The algorithm should probably prefer being a bit late than early too.)