Improving KVM Performance With A Tickless Kernel

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Linux

Avi Kivity suggested that combining KVM, the Kernel-based Virtual Machine, with the dyntick patch could improve overall KVM performance. He noted that it would likely improve performance of both the host by "avoiding expensive vmexits due to useless timer interrupts," as well as on the guest by "reducing the load on the host when the guest is idling (currently an idle guest consumes a few percent cpu)".

Ingo Molnar pointed out that KVM with his -rt kernel already works with dynticks enabled on both the host and the guest, "using the dynticks code from the -rt kernel makes the overhead of an idle guest go down by a factor of 10-15". Ingo added that he hopes the dyntick patch will be ready to be merged into the upcoming mainline 2.6.21 kernel.

Rik van Reil noted that there were other ways to reduce the load of the guest when it's idling,

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