Comment 26 for bug 1100843

I have a few VMs (precise) that process high-volume transaction jobs each night. After I've done a live-migrate operation to replace faulty power supply on a bare-metal server, we encountered sluggish performance on the migrated VMs, significant higher CPU is recorded in particular, where the same nightly job would consume way more CPU and took more time to finish on identical hardware.

Upon investigation, we noticed that the only change introduced was the "live migrate" operation. Upon rebooting the guest OS of the VMs, the performance is back to normal. I suspect we're hitting the same problem as the one filed here.. I will attempt to run lmbench next to see if I would notice similar behavior on system calls costs as the one recorded in comments #19..21,23.

Latest KVM is used from Ubuntu 12.04 LTS :: qemu-kvm (1.0+noroms-0ubuntu14.8)