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Subject: Re: SMP cpu deep sleep
From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: Bill Davidsen <davidsen@tmr.com>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
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On Llu, 2004-08-23 at 22:30, Bill Davidsen wrote:
> For power saving, HLT is hard to beat ;-) You note HLT as if there was 
> some good reason not to use it...

On a large number of processors HLT has only small effect because the
processor still has to do bus arbitration , still has large leakage
currents and has other circuitry running. The PowerNow stuff seems to
make a much bigger difference but has limits to how low you can go.