Re: [Qemu-devel] commit b1bbfe72 causes huge slowdown with no kvm

[Paolo Bonzini]

Il 20/11/2013 14:47, Alex Bligh ha scritto:
> I think you are saying this sounds like another underlying bug
> (no pause instruction) uncovered by the timer patches rather than
> a bug in the timer patches.
> 
> Reading
>  http://software.intel.com/file/27087
> perhaps the answer is for pause to yield the lock.
> 
> However, what if an arbitrary guest foolishly /does/ do a tight
> spinlock without calling pause?

It would be a problem.  I don't think it has to be fixed though (and
anyway of course not now).

The fix could be to make TCG use "real" SMP instead of round-robin.

Paolo