Fix Clock Speed on VMWare; Host:Ubuntu Guest:WinXP

I started using my VOIP software on the guest WinXP today (since the VOIP Provider didn’t provide Linux version). I called and the timer showed more than one hour, when it felt like 20 minutes or so. Well, I had a great chat, so I didn’t really think about it. I realized the clock speed was waay to fast when I called for the second time. It was like 10 seconds, counted as more than a minute?!

I checked the clock on the guest XP and it was speeding very nasty. To make the post short, here’s what I did:

sudo gedit /etc/vmware/config
(edit the config as superuser)

Then add:

#edit your cpu clock, this shows 1.0 GHz
host.cpukHz = 1000000
host.noTSC = TRUE
ptsc.noTSC = TRUE

If you want to synchronize host-guest, add: (it only syncs forwards, not backwards. Didn’t help in speeding cases like mine)
In the guest *.vmx file:

tools.syncTime = TRUE

We can keep a difference of time in host-guest if we want:

tools.syncTime = FALSE
time.synchronize.continue = FALSE
time.synchronize.restore = FALSE
time.synchronize.resume.disk = FALSE
time.synchronize.shrink = FALSE

We can also make the guest clock slower by increasing the value of the processor speed. I suggest to add a little more than the original, because there are some issues in the power down mode of the processor. It can cause a sudden speed-up of clock cycles. If the guest is a little slower, it would be fine as it can sync periodically.

If sudden speed-up is the case, add:

timeTracker.catchupPercentage = 200
timeTracker.catchupIfBehindByUsec = 60
timeTracker.giveupIfBehindByUsec = 50000000


Posted on July 28, 2008, in Linux and tagged , , . Bookmark the permalink. Leave a comment.

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