[libvirt-users] [API reference] confused by CPU time term

[Zhihua Che]

Hi, everyone
    I'm writing a virtual machine monitor based on libvirt. As I read
the api reference, I found I'm confused by some terms.

1, What is cumulative I/O wait CPU time?
    API reference says that VIR_NODE_CPU_STATS_IOWAIT indicate
cumulative I/O wait CPU time.  I'm confused by this time. As far as I
know, when cpu meets IO wait situation, it will schedule another task,
so, how this IO wait time is accounted?

2, How do I get VCPU runtime?
    In my mind, VIR_DOMAIN_CPU_STATS_CPUTIME indicates the physical
cpu time consumed by the domain. Is there any API by which I can query
virtual CPU running stats in one domain?