Kvm slow windows 2008 server with ms sql

KVM slow with win 2008 server installed with ms sql

Apparantly MS implemented a new timer system on sql servers which makes the host cs 1024/sec.

This is quite annoying and will up your cpuload from having to switch constantly alone.

Easy fix is to disable the new timer system and revert to the old.

A workaround is listed here:

http://h20000.www2.hp.com/bizsupport/TechSupport/Document.jsp?objectID=c02110402&lang=en&cc=us&taskId=101&prodSeriesId=3896111&prodTypeId=3709945&aoid=35252

In my case it brough the guest down from ~30-40% constant cputime to about 5-10%.