Testbed and methods

All test run on a Dell D620 laptop. The complete system specifications are:

  • Core2 T7200 CPU @ 2.0 GHz
  • 4 GB of DDR2-667 RAM
  • Quadro NVS110 videocard (used in text-only mode)
  • a Seagate ST980825AS 7200 RPM 80 GB SATA hard disk drive (in IDE compatibility mode, as the D620's BIOS does not support AHCI operation)
  • CentOS 6.5 host-side OS with kernel version 2.6.32-431.
  • a 512 MB ramdisk driver used for disk speed measurements

On the guest side, we have:

  • a first CentOS 6.5 guest (kernel version 2.6.32-431.
  • a second Windows 2012 R2 x64 virtual machine

The VirtIO paravirtualized drivers are already included in the standard Linux kernel, so for the CentOS guest no special action or installation was needed. On the Windows guest, I installed the VirtIO disk and network drivers from the virtio-0.1-74.iso package.

For quick disk benchmark, I used dd on the Linux side and ATTO on the Windows one. To pose additional strain on guest disk subsystem and the host virtualizer, I run all disk tests against a ramdisk drive: in this manner I was sure that eventual differences were not masked out by the slow mechanical disk. Networking speed was measured with the same tool on both VMs: iperf, version 2.0.5.

Host CPU load was measured using mpstat.

Ok, let see the numbers...