VMWare clockspeed/timekeeping

oceaness

oceaness

oceaness

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Has anyone else experienced problems with timekeeping in VMWare?

VMWare gave me this message.

VMware Workstation has measured your CPU speed to be 2666 MHz, but Windows reports that it is 2670 MHz. This may mean that your computer has a power-saving feature that varies the processor speed. As a result, the clock in your virtual machine may run too fast or too slow.

For a workaround, please refer to the VMware knowledge base article at:
http://vmware.com/info?id=97.
Click to expand...

One of biggest problems I found when I was running it was how the clock always went massively out so I dont know if anyone might find the article linked to useful :)

Of course anyone with an overclock should have things like Speedstep and CoolnQuiet disabled anyway so for the large majority this probably shouldn't be an issue.

Though FAH would strss the CPU for the duration of a unit, inbetween WU's it's possible that the CPU speed could relax if CPU powersaving features are enabled.
 
I found this article whilst looking for something a different, but has an interesting comment related to clocks - i personally have never had a problem with vmware getting the time wrong, but it does say in the article that vmware server 2 was optimised for OSes that have a 100Hz clock, as opposed to the 1000Hz clock found in most desktop OSes. It shows a way to change the clock ticker frequency for linux - it may work, i have no idea (also no idea how safe it is to do it, but its a vm, so it cant be all that dangerous!), but you may want to give it a go?

http://www.stress-free.co.nz/vmware_server_2_finally_goes_gold
 
VMWare tools has an option for using the host OS for providing time. Alternatively you can try to get NTP working but I've found it a royal pain on Linux.
 
VMWare tools can only make the guest clock catch up to the host clock if its lagging, if it's runnning fast there's very little you can do about it.

So far so good got two VM's running and they've been completely stable :)
 
Thanks for this - I always had problems with the timekeeping in VMs. VMWare tools is useful for updating the time if you've suspended your VM rather than shutting it down, as I used to. It's also useful to remember that if you use anything non-BIOS based to apply an overclock, this will most likely make the clock run fast as well.
 
The VMWare Timekeeping PDA file, linked to at the bottom of the linked article in my original post has some very in depth information if you can understand it.

So far my VM's appear to be working ok, but it will be interesting to see how it goes over the course of a couple of weeks or more.
 
Biffa said:
NTP is your friend, just set it to update from a machine on the network every minute :P
Click to expand...

Yup I did that before, but for NTP to work it has to be within a certain amount either way of the current time.

My VM's sometimes went years out.

This newer version does seem to be an awful lot better, the clocks appear to be ever so slightly faster than the host, but NTP will be able to cope with that :)
 
oceaness said:
Yup I did that before, but for NTP to work it has to be within a certain amount either way of the current time.

My VM's sometimes went years out.
Click to expand...
You can use ntpdate to sort that, or edit /etc/ntp.conf and add the following line at the end:

Code: 
tinker panic 0
 
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