RFC: powerd algorithms enhancements

[Ian Smith]

On Tue, 11 Nov 2008, Alexandre "Sunny" Kovalenko wrote:
 > On Tue, 2008-11-11 at 15:56 -0200, Nenhum_de_Nos wrote:
 > > On Tue, November 11, 2008 3:20 am, Ian Smith wrote:
 > > > On Mon, 10 Nov 2008, Nenhum_de_Nos wrote:
 > > >  > as all you are talking about the subject, and I read all messages, is
 > > >  > there any module to load and make my AthlonXP 1700+ use less power ?
 > > >  >
 > > >  > running 7-STABLE, just a file server. any acpi-stuff I could enable
 > > > would
 > > >  > be great, as I just use all its power when compiling ...
 > > >
 > > > What does 'sysctl hw.acpi dev.cpu' have to say?
 > > 
 > [...]

Reinjecting a bit ..

 > hw.acpi.thermal.user_override: 0
 > hw.acpi.thermal.tz0.temperature: 43.0C
 > hw.acpi.thermal.tz0.active: -1
 > hw.acpi.thermal.tz0.passive_cooling: 1
 > hw.acpi.thermal.tz0.thermal_flags: 0
 > hw.acpi.thermal.tz0._PSV: 66.0C
 > hw.acpi.thermal.tz0._HOT: -1
 > hw.acpi.thermal.tz0._CRT: 70.0C
 > hw.acpi.thermal.tz0._ACx: 66.0C -1 -1 -1 -1 -1 -1 -1 -1 -1
 > hw.acpi.thermal.tz0._TC1: 4
 > hw.acpi.thermal.tz0._TC2: 3
 > hw.acpi.thermal.tz0._TSP: 60
 > hw.acpi.cpu.cx_lowest: C1

Certainly no cpu frequency control.  Surprisingly low _CRT temperature 
but unless it ever actually gets too hot, it's not a problem.  I don't 
really follow why .passive-cooling=1 with no cpufreq driver/s attached?

 > > [root at xxx ~]# sysctl dev.cpu
 > > dev.cpu.0.%desc: ACPI CPU
 > > dev.cpu.0.%driver: cpu
 > > dev.cpu.0.%location: handle=\_PR_.CPU0
 > > dev.cpu.0.%pnpinfo: _HID=none _UID=0
 > > dev.cpu.0.%parent: acpi0
 > > dev.cpu.0.cx_supported: C1/0 C2/90 C3/900
 > > dev.cpu.0.cx_lowest: C1
 > > dev.cpu.0.cx_usage: 100.00% 0.00% 0.00%
 > > [root at xxx ~]#
 > > 
 > > if it rings any bells :)
 > All I can suggest here is 
 > 
 > sysctl dev.cpu.0.cx_lowest="C3"
 > 
 > or, if it gets you totally unresponsive machine, 
 > 
 > sysctl dev.cpu.0.cx_lowest="C2"
 > 
 > how much of the power saving you will see from this is the
 > separate question.

If that works to any extent you'll notice some drop in cpu temperature.  
I do see a slight but noticeable idle temp. drop on my T23 in C2, though 
nothing compared to the power reduction of lower frequency (about half).

cheers, Ian