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Re: [Xen-devel] credit based scheduler

On 21 Jun 2006, at 22:26, Emmanuel Ackaouy wrote:

Second, migration or not, once you start time-slicing, you have
to deal with cache warming costs. The important thing is to run
long enough time slices to take advantage of the cache.

Yep, locality across timeslices doesn't really help. If you've run a different VCPU between timeslices then the caches will be cold. Even if there is a small cache advantage, it's very unlikely to balance the cost of deliberately leaving CPUs idle. Things may be more interesting in NUMA environments, but there's always the per-VCPU affinity map to restrict cross-CPU scheduling to within a NUMA node.

 -- Keir

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