Messages in this thread | | | Date | Tue, 22 Jan 2008 20:27:44 +0100 | From | Ingo Molnar <> | Subject | Re: Rescheduling interrupts |
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* Matt Mackall <mpm@selenic.com> wrote:
> > amarokapp does wake up threads every 20 microseconds - that could > > explain it. It's probably Xorg running on one core, amarokapp on the > > other core. That's already 100 reschedules/sec. > > That suggests we want an "anti-load-balancing" heuristic when CPU > usage is very low. Migrating everything onto one core when we're close > to idle will save power and probably reduce latencies.
that would probably be the case if it's multiple sockets - but for multiple cores exactly the opposite is true: the sooner _both_ cores finish processing, the deeper power use the CPU can reach. So effective and immediate spreading of workloads amongst multiple cores - especially with shared L2 caches where the cost of migration is low, helps power consumption. (and it obviously helps latencies and bandwith)
Ingo
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