Re: [Xen-devel] credit based scheduler

[Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>]

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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