Re: [PATCH documentation 1/2] nohz1: Add documentation.

From: Arjan van de Ven
Date: Fri Apr 12 2013 - 13:56:40 EST



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1. It increases the number of instructions executed on the path
to and from the idle loop.

2. On many architectures, dyntick-idle mode also increases the
number of times that clocks must be reprogrammed, and this
reprogramming can be quite expensive.


it's really that we're no longer using periodic clocks, but only one-shot clocks only.
(which then leads to having to program them every time)

but arguably, that's because of HRTIMERS more than NOHZ
(e.g. I bet we still turn off periodic even for nohz as long as hrtimers are enabled)

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