Wednesday, October 3, 2007

Ubuntu Host with Windows Guest Time Sync Problem

I've been running VMware server for 3-4 months on an Intel Duo Core 2 with Ubuntu Fiesty Fawn as my host OS. My windows guests would always run too fast and every article I could find about time sync issues only showed how to change the boot clock variable to clock=pit or clock=pmtmr under grub or lilo.

The problem and fix are different from what this vmware knowledgebase article. Clock in a Linux Guest Runs More Slowly or Quickly Than Real Time

This is the correct knowledgebase article from vmware. Host Power Management Causes Problems with Guest Timekeeping (Windows Hosts)

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Quick Solution Steps

Install cpufrequtils and run cpufreq-info to get maximum frequency

Autoedification: VMware guest clock runs fast
Since my max CPU is 1.83 GHz, I added these lines to
/etc/vmware/config:

host.cpukHz = 1830000
host.noTSC = TRUE
ptsc.noTSC = TRUE

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Unfortunately, you will have to modify this file every time you run vmware-config to recompile the vmware modules for a new kernel.  I'm going to keep a copy under /etc/vmware/config.bak and run a quick 'sudo cp /etc/vmware/config{.bak,}'  after every time I need to recompile.


3 comments:

  1. Thanks for this post! I've been having issues with this for some time now - this worked perfect on Gutsy!

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  2. Why can't one use the syncing option from the guest vmware tools? There is an option to sync the guest clock to the host clock..??

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