Re: kvm & dyntick

[Rik van Riel <riel@redhat.com>]

Avi Kivity wrote:

> dyntick-enabled guest:
> - reduce the load on the host when the guest is idling
>   (currently an idle guest consumes a few percent cpu)

You do not need dynticks for this actually.  Simple no-tick-on-idle
like Xen has works well enough.

While you're modifying the timer code, you might also want to add
proper accounting for steal time.  Time during which your guest
had a runnable process, but was not actually running itself, should
not be accounted against the currently running process.

I wonder if it would be possible to simply copy some of the timer
code from Xen.  They have the timing quirks worked out very well
and their timer_interrupt() is pretty nice code.

(Now I need to buy myself another VT box so I can help out with KVM :))

http://virt.kernelnewbies.org/ParavirtBenefits has some other features
you may want to have :)))

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