Messages in this thread | | | Date | Fri, 30 Jul 2010 06:57:14 -0700 | From | Arjan van de Ven <> | Subject | Re: [patch] Remove the per cpu tick skew |
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On Fri, 30 Jul 2010 17:27:04 +1000 Nick Piggin <npiggin@suse.de> wrote: > > Nowadays, with the tickless kernel, this contention no longer > > happens since time keeping and updating are done differently. In > > addition, this skew is actually hurting power consumption in a > > measurable way on many-core systems. > > Question, how much of a win is it? What does it do that tickless > idle does not, can you explain?
tickless idle works great if you're really almost idle
if there's "some work but not fully busy" this still matters
this is not about 'a few milliwatts', but on a server in our labs (sorry, no hardware details in public) this effect is in the "several dozen Watts" range.
-- Arjan van de Ven Intel Open Source Technology Centre For development, discussion and tips for power savings, visit http://www.lesswatts.org
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