Re: [kvm-devel] Réf. : Re: [PATCH 0/4] Virtual Machine Time Accounting

[Christian Borntraeger <borntraeger@de.ibm.com>]

Am Montag, 20. August 2007 schrieb Glauber de Oliveira Costa:
> Although I don't know KVM to a that deep level, I think it should be
> possible to keep the virtual cpus in different process (or threads),
> and take the accounting time from there. Perfectly possible to know
> the time we spent running (user time), and the time the hypervisor
> spent doing things on our behalf (system time).

I disagree here. First thing, you dont want to have the virtual cpu in a 
different process than the hypervisor control code for that cpu. Otherwise  
communication has to be made via IPC. 
Secondly, Its not qemu/kvm that does the accouting. Its existing userspace 
code like top/snmp agents and clients! etc. that would require additional 
knowledge which thread is guest code.

I personally like the approach Laurent has taken. Maybe it needs some polish 
and maybe we want an account_guest_time function, but in general I think he 
is doing the right thing. 

Christian