Asynchronous interruption of a compute-intensive guest

[Tommaso Cucinotta <tommaso.cucinotta@sssup.it>]

Hi,

I'd like to "intercept" from the host the exact times at which an 
incoming network packet directed to a guest VM:
a) is delivered from the host OS to the KVM process;
b) is delivered to the "CPU thread" of the KVM process.

Specifically, I don't have a clean idea of how b) happens when the CPU 
thread is doing compute-intensive activities within the VM. How is the 
flow of control of such thread asynchronously interrupted so as to hand 
over control to the proper network driver in kvm ? Any pointer to the 
exact points to look at, in the KVM code, are also very well appreciated.

Just in case you're interested, we need this for playing with some 
custom CPU scheduling policy we have at our lab, for the purpose of 
facing with the problem of responsiveness of VMs while doing 
CPU-intensive activities (i.e., a mixed batch/interactive guest).

Thanks very much for your kind help.

Regards,

     T.

-- 
Tommaso Cucinotta, Computer Engineering PhD, Researcher
ReTiS Lab, Scuola Superiore Sant'Anna, Pisa, Italy
Tel +39 050 882 024, Fax +39 050 882 003
http://retis.sssup.it/people/tommaso