[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] cpu utilization monitoring
The hypercall reports the point-of-view of the timeline of that VCPU. The fact that its timeline may involve running on various different physical CPUs should not matter, except for cache-warming and other context-switching costs. The runstate_info interface absolutely does not state that the reported run time only includes time spent running on the currently assigned physical CPU. -- Keir On 11/9/06 8:44 pm, "Karl Rister" <kmr@xxxxxxxxxx> wrote: > Currently in the vcpu_runstate_info structure we have fields that contain the > time spent when the vcpu is in one of four states. When trying to determine > the physical utilization that a vcpu is requiring of the system from libxc we > make a domctl operation call to the XEN_DOMCTL_getvcpuinfo command. When > processing this command we pull the value for the RUNSTATE_running field and > attribute it to the processor that the vcpu is currently running on. > > I believe that with the new credit scheduler these values are wrong as it is > possible that the vcpu has time in RUNSTATE_running that was not actually > spent on the currently running processor. Is there a separate path through > the libraries and into Xen that retrieves this information in a more correct > manner? Given that a vcpu can migrate among several physical processors in > the time between samples it seems that a finer grained accounting mechanism > is needed to correctly report physical utilization of the hardware resources. > > _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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