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The VIR_DOMAIN_STATS_VCPU flag to virDomainListGetStats enables reporting of stats about vCPUs. Currently we only report the cumulative CPU running time and the execution state. This adds reporting of the wait time - time the vCPU wants to run, but the host scheduler has something else running ahead of it. The data is reported per-vCPU eg $ virsh domstats --vcpu demo Domain: 'demo' vcpu.current=4 vcpu.maximum=4 vcpu.0.state=1 vcpu.0.time=1420000000 vcpu.0.wait=18403928 vcpu.1.state=1 vcpu.1.time=130000000 vcpu.1.wait=10612111 vcpu.2.state=1 vcpu.2.time=110000000 vcpu.2.wait=12759501 vcpu.3.state=1 vcpu.3.time=90000000 vcpu.3.wait=21825087 In implementing this I notice our reporting of CPU execute time has very poor granularity, since we are getting it from /proc/$PID/stat. As a future enhancement we should prefer to get CPU execute time from /proc/$PID/schedstat or /proc/$PID/sched (if either exist on the running kernel) Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
LibVirt : simple API for virtualization
Libvirt is a C toolkit to interact with the virtualization capabilities
of recent versions of Linux (and other OSes). It is free software
available under the GNU Lesser General Public License. Virtualization of
the Linux Operating System means the ability to run multiple instances of
Operating Systems concurrently on a single hardware system where the basic
resources are driven by a Linux instance. The library aim at providing
long term stable C API initially for the Xen paravirtualization but
should be able to integrate other virtualization mechanisms if needed.
Daniel Veillard <veillard@redhat.com>