Re: [Results] [RFC PATCH v4 00/40] mm: Memory Power Management

[Arjan van de Ven]

On 9/25/2013 4:47 PM, Andi Kleen wrote:
> > Also, the changelogs don't appear to discuss one obvious downside: the
> > latency incurred in bringing a bank out of one of the low-power states
> > and back into full operation.  Please do discuss and quantify that to
> > the best of your knowledge.
>
> On Sandy Bridge the memry wakeup overhead is really small. It's on by default
> in most setups today.

yet grouping is often defeated (in current systems) due to hw level interleaving ;-(
sometimes that's a bios setting though.

in internal experimental bioses we've been able to observe a "swing" of a few watts
(not with these patches but with some other tricks)...
I'm curious to see how these patches do for Srivatsa

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