Hello
Yeasterday, I noticed a strange behaviour on my WinXP guest (host is
kubuntu 7.04).
When the guest is launched, it is *VERY* slow. When looking at the task
manager, the processor is used at 100%, doing quite noting.
Note that the guest's cpu consumption is never accurate using
virtualization since the hypervisor does not provides fare time slices
to the guest,
thus causing inaccurency for the hvm scheduler.
Please checkout what the host is doing.
You can see what's the guest does by using strace on qemu process and
using the kvm_stat script that comes with kvm's userspace source code.
Kvm_stat details the amount of VM exits of every type.
After having thought hardly, I arrrived to the conclusion that KVM
itself uses his processor time to allocate memory for the guest (and so
the guest has no more CPU time). When the memory used by KVM process is
the same as the "-m XXX" option, the speed of guest becomes quite normal
(still slow but usable).
The host indeed allocates the memory for the guest but this is done only
once and much before the guest's enters graphic mode.
Of course, this "allocation time" is biger as the "-m XXX" is bigger.
This behaviour happend after having tried to install gnome instead of
KDE and after havin tried to remove what I installed with gnome.
Do you have any idea where to look at to find the problem?
Are you using SDL or vnc for graphics? Try using vnc and tell is the
problem continues.
Bye
Cyril
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