[virt-tools-list] KVM virtual server CPU utilization shown on virt-top implies more than 100% of virtual CPUs in use

[Yuksel Gunal]

I have been playing with KVM virtual servers on Red Hat and used the virt-top tool to monitor CPU utilization. I am puzzled by an observation that I was wondering if someone could explain: I have a 32-CPU blade and a KVM virtual server with 2 virtual CPUs on it. I am running some tight loops in this virtual server and pushing the CPU usage on it. What I see on virt-top is 7% utilization for this virtual server. The way I interpret it is 7% of 32 CPUs, which is 2.24 CPUs in use (7 * 32 / 100). What I am puzzled about is that I would not have expected this virtual server to use more than 2 CPUs since it only has 2 virtual CPUs assigned. Is it expected that KVM virtual servers could consume more than the number of virtual CPUs assigned to them or is this a known Linux accounting problem?  


Yüksel Günal
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