[NTLUG:Discuss] Weird VMWare Performance

[Chris Cox]

Kenneth Loafman wrote:
> Chris Cox wrote:
>> David Simmons wrote:
>>> While I don't think we have any VMWare experts (maybe we do), was hoping
>>> maybe someone would have some pointers as to where to start researching
>>> and/or other tech support groups to contact.  Thanks in advance.
>>>
>> VMware does not (and they don't want to fix this) understand
>> multi frequency CPUs.  One thing you can try is prior to starting
>> VMware you can change your max_cstate to 1.
> 
> Interesting!  I've never had a problem with frequency scaling CPU's, but
> I use mostly AMD's so this may not apply.  This is highly important in
> laptops (I'm running 2 VMs right now - the thing would melt if it had to
> run without letting it scale down.).
> 
> Do you have a cite from VMware on this?  I tried Google, but no results
> match.  I have seen the 'host clock change request' messages in syslog,
> but these are just informative as far as I can tell.
> 
> I am curious if the max_cstate change will fix the issue.

Not a fix.  Again, VMware isn't going to fix this.  It's a case of
the VMware folks pointing at the kernel folks and the kernel folks
pointing at the VMware folks.

Lowering the max_cstate may merely help.  This is especially
true if you've seen that your VMware session accelerates to
normal speeds when
you do something (e.g. move the mouse around a lot).

The problems is sort of two fold.  One: multi frequency chips,
Two: the high resolution kernel timer.