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Date:      Mon, 16 Aug 2004 08:06:30 -0700
From:      Colin Percival <colin.percival@wadham.ox.ac.uk>
To:        freebsd-mobile@freebsd.org
Cc:        freebsd-current@freebsd.org
Subject:   Enhanced SpeedStep driver available
Message-ID:  <6.1.0.6.1.20040816074348.03f99338@popserver.sfu.ca>

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  Thanks to everyone who has been sending me data about their
processors (and in particular, the 90nm versions), I now have
a first draft of a Enhanced SpeedStep driver available.  For
people with the appropriate processors (Pentium M only), this
makes it possible to adjust the cpu frequency via a new sysctl
(hw.est_curfreq), and have the cpu voltage adjusted at the
same time.
  I've also put together a very simple control daemon which
reads kern.cp_time every second and adjusts the cpu frequency
based on the fraction of cpu time which is idle.  This increases
my laptop's battery life by around 40%.
  All the code is online at
http://www.daemonology.net/freebsd-est/
  Assuming I don't hear any major bug reports in the next few
days, I'll package these into ports and hopefully get them into
the ports tree in time for 5.3-RELEASE.

Colin Percival



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