On Thu, Apr 05, 2012 at 06:06:43PM +0800, Zhihua Che wrote:
Hi, everyone
I'm writing application using libvirt and I need call virDomainGetCPUStats to get domain cpu stats . I learn from API reference that this function has to be called when domain is running. So my question is if there is an atomic way to test the domain's state and get its stats?
Or, it's ok to call this function when domain is not active, but caller just gets error returned.
In my code, I just call it directly and return error. I wonder if this programming practice has subtle problem like race condition.
AFAIK there is no way to do this without a race, not least because a VM can power itself off / crash at literally any time. In virt-top, we just catch the error and ignore it. Rich. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones Read my programming blog: http://rwmj.wordpress.com Fedora now supports 80 OCaml packages (the OPEN alternative to F#) http://cocan.org/getting_started_with_ocaml_on_red_hat_and_fedora