Messages in this thread | | | Date | Wed, 10 Jul 2002 14:28:03 -0700 | From | Andrew Morton <> | Subject | Re: HZ, preferably as small as possible |
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"Grover, Andrew" wrote: > > I'd like to see HZ closer to 100 than 1000, for CPU power reasons. Processor > power states like C3 may take 100 microseconds+ to enter/leave - time when > both the CPU isn't doing any work, but still drawing power as if it was. We > pop out of C3 whenever there is an interrupt, so reducing timer interrupts > is good from a power standpoint by amortizing the transition penalty over a > longer period of power savings.
That makes a ton of sense.
> But on the other hand, increasing HZ has perf/latency benefits, yes? Have > these been quantified?
Not that I'm aware of. And I'd regard any such claims with some scepticism.
> I'd either like to see a HZ that has balanced > power/performance, or could we perhaps detect we are on a system that cares > about power (aka a laptop) and tweak its value at runtime?
It's all rather fishy.
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