Comment # 16 on bug 967862 from Jan Beulich

(In reply to Per Jessen from comment #15)
> "max_cstate=1" did the trick, the system is now much snappier, no pressing
> keys needed.  Is this some BIOS option that I need to change, Jan?  I'm
> using the defaults for this system, but I see settings such as
> 
> Enhanced SpeedStep  y/n
> Enhanced Idle Power State  y/n

Maybe worth trying (more likely for the latter than the former), but you never
know what exactly hides behind those.

In the end right now we only know there is an issue (perhaps interrupt signals
getting lost) _somewhere_. Could be due to hardware, firmware, or software. So
far no hypervisor log has been attached here, so I can't even judge which of
the C-state drivers is being used. If it's the MWAIT one, suppressing its use
and using the ACPI one would be another thing to try. If the latter works,
precise CPU model information would be needed, along with indication whether
the intel_idle driver in Linux doesn't cause such hick-ups.