17 Aug 08 VMware Time Problems

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Using VMware Server on an SMP machine has long caused me problems.

Although the host machine’s clock generally remains correct, the guest machines are often 2-5 times too slow. Running a local time server is just a hack besides which, running ntp each minute is really horrible.

Various posts indicate that you can add various parameters to the guest’s boot configuration such as, acpi=off nosmp noapic nolapic clock=pit

I’ve had limited success with various of these combinations and as the config says, there’s no SMP and VMware Server supports guests with 2 CPUs!

I came across another post related to changing the kernel’s tick speed. On the host, I compiled a custom kernel, taking the debian etch default config, and changing tick speed from it’s 250Hz to 1000Hz, recompiled and rebooted. Now the guests with their regular kernels and no command line hacks keep their times perfectly. I can also use 2 CPUs

From what I can see, as long as the host tick is faster than the guest, you’re fixed. I’ve tested it with a 1000Hz host and a 250Hz guest, however you might have success leaving the host at 250Hz and compiling a custom guest at 100Hz

Would be interested in any feedback

Tags: VMware SMP Time Clock Problems