VMware Guests Time Runs Too Fast!

While setting up my latest server i encounter an issue i have never come across before, in my VMware guest machine the time was flying very quickly into the future. Could this be time travel?

Unfortunately not, its caused by the CPU frequency scaling on a multi-core processor and by default VMware doesn't quite no how to deal with it yet.

To rectify this issue you have to set your CPU's max frequency into /etc/vmware/config.

To find your cpu's frequency you have two options, the first:

$ cat /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_max_freq 

2000000

The second:

$ cpufreq-info

cpufrequtils 002: cpufreq-info (C) Dominik Brodowski 2004-2006

Report errors and bugs to linux@brodo.de, please.

analyzing CPU 0:

  driver: centrino

  CPUs which need to switch frequency at the same time: 0

  hardware limits: 1000 MHz - 2.00 GHz

  available frequency steps: 2.00 GHz, 1.33 GHz, 1000 MHz

  available cpufreq governors: userspace, powersave, ondemand, conservative, performance

  current policy: frequency should be within 1000 MHz and 2.00 GHz.

                  The governor "ondemand" may decide which speed to use

                  within this range.

  current CPU frequency is 1000 MHz.

analyzing CPU 1:

  driver: centrino

  CPUs which need to switch frequency at the same time: 1

  hardware limits: 1000 MHz - 2.00 GHz

  available frequency steps: 2.00 GHz, 1.33 GHz, 1000 MHz

  available cpufreq governors: userspace, powersave, ondemand, conservative, performance

  current policy: frequency should be within 1000 MHz and 2.00 GHz.

                  The governor "ondemand" may decide which speed to use

                  within this range.

  current CPU frequency is 1000 MHz.

As my MAX CPU frequency is 2.00GHz i added these lines to /etc/vmware/config

host.cpukHz = 2000000

host.noTSC = TRUE

ptsc.noTSC = TRUE

All that is left to do now is restart VMware and test the results.

The above commands where performed on:

Host: VMware Server 1.5.0 running on a 2.6 kernel

Guest: Ubuntu 8.04 Hardy Heron

Please post any comments or suggestions.