Setting frequency limits

btrip · n00b Joined: 06 Mar 2004 Posts: 14

I'm using an IBM thinkpad T30 and I'm trying to set up dynamic memory allocation using speedfreq.

Speedfreq has no problem dynamically allocating the clock speed between 2.0 GHz and 1.2GHz

However the minimum clock speed is still too high for me; since power usage is important.

Does anyone know if/how I can change the bottom limit to something lower???

Any help would be appreciated.

Brian

nabla · Posted: Fri Mar 26, 2004 10:21 am Post subject:

hi,

i have a t40 (with pentium m).
i think that you can't go under the hardware specific limit. with a cat /sys/.../min_freq you can find out your lower limit. since i'm on a windows machine right now, i can't give you the exact path.

another possibility would be cpu throtteling, which puts the processor in sleepstate for a defined amount of time. this can be found in /proc/acpi/processor/...

i dont know if your processor supports cpu throtteling, but with this you can save more power.

hope that helps
cu nabla

Earthwings · Posted: Fri Mar 26, 2004 5:55 pm Post subject:

Throttling doesn't save much energy. It's main use is keeping the temperature low.

soviet/funk · Posted: Mon Mar 29, 2004 9:50 pm Post subject:

My minimum freq seems to be listed as 1200MHz in
/sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_min_freq
but i do seem to remember seeing a freq as low as 700 the last time i bothered saving some power in XP. Machine is a T30 w/~1800 cpu.

Does speedfreq adjust powersaving and dynamic profiles according to the number in this file?

s/f

brodo · Guru Joined: 15 Apr 2003 Posts: 319

damianfrancis · Tux's lil' helper Joined: 25 Aug 2003 Posts: 120

brodo are you suggesting not to worry about using cpudyn or speedfreq? You know what would actually be nice, if you could set the machine to keep the cpu max mhz at a certain level under certain curcumstances, such as you have it unplugged and you know you are going to want to conserve power, or to have it change into a higher power usage mode when running certain programs. Anyway, does anyone know how I check to see if speedfreq is working or what mhz my machine is running at. gkrealm tells me how much of the power it is running at it is using but not much more than that.
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adastra · Tux's lil' helper Joined: 16 Oct 2002 Posts: 106

For x86 processors, I learned of a handy little tool called x86info.

brodo · Guru Joined: 15 Apr 2003 Posts: 319