On Thu, 3 Jun 2010 19:26:50 -0700 (PDT) Linus Torvalds <[email protected]> wrote:
> > If the system is idle (or almost idle) for long times, I would > heartily recommend actively shutting down unused cores. Some CPU's > are hopefully smart enough to not even need that kind of software > management, but I suspect even the really smart ones might be able to > take advantage of the kernel saying: "I'm shutting you down, you > don't have to worry about latency AT ALL, because I'm keeping another > CPU active to do any real work". sadly the reality is that "offline" is actually the same as "deepest C state". At best. As far as I can see, this is at least true for all Intel and AMD cpus. And because there's then no power saving (but a performance cost), it's actually a negative for battery life/total energy. (lots of experiments inside Intel seem to confirm that, it's not just theory) -- Arjan van de Ven Intel Open Source Technology Centre For development, discussion and tips for power savings, visit http://www.lesswatts.org -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
