Ubuntu Wiki

Overview

This page is will list

• a set of features whose performance impacts we think are worth studying
• instructions to reproduce reliable measurements
• Results

Once we have these measurements, we can apply what we've learned to make recommendations (at KvmWorkloads) based on specific workloads.

Features to measure

• drive format (qcow2, raw (file), raw (LVM), qed)
• driver interface (virtio, scsi, ide)
• cache performance (cache=none, writeback, unsafe, writethrough)
• nic model (rtl8139, virtio)
• network type (tap, user)
• swap or no swap?
• overcommit types
  • none, ksm, balloon, both ksm and balloon
  • for ksm, try 1 oneiric VM, 2 oneiric VMS, and 1 oneiric and 1 lucid VM.
• Guest root filesystems (xfs, jfs, ext4, ext2)
  • test each with both virtio and scsi)
• Host filesystem. (xfs, jfs, ext4)
• Guest memory (128M,256M,512M, 1024M, 2048M)
  • with and without swap?
• Guest smp (1,2,4,8)

Tests could include kernbench, dbench, unixbench.

Reproduction instructions

General advice: use the same system as much as possible for each test. My plan is to have one system, re-install for each test with the same preseed to ensure the same filesystem layout.

Results