Guest virtual CPUs limited to only 50% of host CPU


#1

Hi,

I am using Qemu-KVM-0.12.5 on Intel Xeon (Vt-x enabled) processors and
monitoring the system using htop on the host. On the processors that
are running Qemu-KVM I am seeing a 50/50 split between userspace and
guest (“gu:” in htop). I have pinned the vCPU qemu-kvm threads to
specific host CPUs using taskset. In the guest the CPUs are nearly
100% userspace in htop.

Does anyone have ideas on why this is? Is there a way I can get much
higher utilization for the guest virtual CPUs wrt the host?

Thanks in advance!


#2

Turns out that htop was reporting it wrong. In /proc/stat utime already includes guest time.