Re: faster boot with -no-kvm?

[Avi Kivity <avi-atKUWr5tajBWk0Htik3J/w@public.gmane.org>]

David Abrahams wrote:
> on Thu Apr 12 2007, Avi Kivity <avi-atKUWr5tajBWk0Htik3J/w-AT-public.gmane.org> wrote:
>
>   
>> David Abrahams wrote:
>>     
>>> When I start my Windows VM with -no-kvm, it seems to boot much more
>>> quickly than without.  
>>>       
>> You probably have acpi enabled in Windows.  This causes massive 
>> slowdowns in kvm; the real fix will unfortunately require you to upgrade 
>> your hardware.
>>     
>
> My physical hardware?  Which part?
>   

The part that currently doesn't virtualize the apic tpr: the cpu.

It happens that Windows in acpi mode likes to bang on this register 
quite a lot, and that the penalty for accessing this register is several 
microseconds (instead of nanoseconds).  Most of the time in a (virtual) 
Windows boot is spent on reading and writing this register.

> Is starting the vm with -no-acpi insufficient?  I just realized, I
> haven't been doing that.
>   

It won't help if Windows wants acpi, I think.

-- 
error compiling committee.c: too many arguments to function


-------------------------------------------------------------------------
Take Surveys. Earn Cash. Influence the Future of IT
Join SourceForge.net's Techsay panel and you'll get the chance to share your
opinions on IT & business topics through brief surveys-and earn cash
http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV