Messages in this thread | | | Date | Fri, 12 Jan 2007 11:19:31 +0100 | From | Ingo Molnar <> | Subject | Re: kvm & dyntick |
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* Ingo Molnar <mingo@elte.hu> wrote:
> > dyntick-enabled guest: > > - reduce the load on the host when the guest is idling > > (currently an idle guest consumes a few percent cpu) > > yeah. KVM under -rt already works with dynticks enabled on both the > host and the guest. (but it's more optimal to use a dedicated > hypercall to set the next guest-interrupt)
using the dynticks code from the -rt kernel makes the overhead of an idle guest go down by a factor of 10-15:
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 2556 mingo 15 0 598m 159m 157m R 1.5 8.0 0:26.20 qemu
( for this to work on my system i have added a 'hyper' clocksource hypercall API for KVM guests to use - this is needed instead of the running-to-slowly TSC. )
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