VMware and max_cstate

I am using VMware on two computers: On my CoreDuo workstation Debian Etch was running with a 2.6.23 Vanilla kernel and VMware Workstation 6.0. And on my Pentium-M Laptop Ubuntu Dapper Drake with VMware Workstation 5 is installed.

On both computers i have Windows XP as a guest. And on both i had massive performance issues on heavy load in XP. If XP was on heavy load then the Linux kernel was still mostly idle. The guest couldn't tell the host to wake up and use more of the CPU. 

Extensive googling brought up an entry in VMware Communities. The advise there was to set the kernel parameter max_cstate to overrule the CPU power managment. On my CoreDuo with 2.6.23 kernel:

maximum performance
echo 1 > /sys/module/processor/parameters/max_cstate
minimum performance
echo 8 > /sys/module/processor/parameters/max_cstate

This advice worked for me and did overcome most of my performance issues. But this is of course only a workaround as the ACPI is manually overridden and so the computer uses more power than necessary!

Lenny & VMware 6.5.2

After the dist-upgrade from Etch to Lenny also a VMware workstation upgrade to version 6.5.2 was necessary as the 6.0 vmware-config.pl produced a lot of error messages with the Lenny kernel. Upgrade to 6.5.2 did run without any problems and without an any-any patch.

When I unzipped 300 MB data in XP, I discovered that VMware now had no more ACPI problems. :-) The VMware had in Linux performance monitor a utilization of 50% without changing max_cstate. Therefore this workaround is no longer needed.