Power saving options

Greetings:

I noticed they added an option in 2.6.18 to improve power savings:

    /sys/devices/system/cpu/sched_mc_power_savings
    /sys/devices/system/cpu/sched_mt_power_savings

In a nutshell, these options alter the scheduler so that lightly loaded
systems schedule processes on only one core or thread pipeline, with the
theory that the completely idle one will draw even less power.

Of course, AMD also has PowerNow, and Intel has SpeedStep, and Linux already
has frequency scaling governors to take advantage of that. That being the
case, has anyone here tested the new scheduler option to see if there's any
additional savings to be had for laptops, etc.?

I'm currently only using the on-demand performance governor on an Intel Duo,
and the stats certainly look impressive
(/sys/devices/system/cpu/cpu?/cpufreq/stats/time_in_state), and battery life
is near what's advertised.

If anyone has any real world experience with the various power options, I'd
like to hear it.

          --Arthur Corliss
            Live Free or Die
---------
To unsubscribe, send email to <aklug-request@aklug.org>
with 'unsubscribe' in the message body.
Received on Wed Apr 4 21:40:40 2007