HOWTO: Configure CPU scaling to decrease heat and increase battery life

[carreira87]

Hello!

I want to change cpu frequency and I tried this tutorial, but in my ubuntu only appears one governor, which is "performance"... I don't know where are the others, and because I only have one governor I can't change the cpu frequency.

How can I get the other governors, like "powersave", "ondemand", ... ?

Thanks in advance!

[carreira87]

Hello!

I want to change cpu frequency and I tried this tutorial, but in my ubuntu only appears one governor, which is "performance"... I don't know where are the others, and because I only have one governor I can't change the cpu frequency.

How can I get the other governors, like "powersave", "ondemand", ... ?

Thanks in advance!

Well, I just solved that problem. Somehow, I manage to remove powernowd, but now I reinstalled and I have other governor modes to choose.

Unfortunately, changing the mode doesn't affect the cpu frequency, which is always at maximum speed.


From this image of the CPU Frequency Monitor, I have frequency options but when I click on those frequencies the cpu frequency remains the same. Clicking on the modes, it change the mode, but again the frequency remains the same.

[carreira87]

Wow! 3 posts in a row!

Ok, I have all my problems solved now. I can choose the frequency now, a simple reboot solved my problem.

[Synchro]

I've tried the things mentioned in this thread with no joy. I'm running 8.04.1 on dual quad-core Xeon L5420 CPUs, and there just doesn't seem to be any support for them in cpufreqd. cpufreq-info just says "no or unknown cpufreq driver is active on this CPU".

I've installed the cpufreqd and cpufrequtils packages, but cpufreqd is marked as failed on startup and /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_governors is just not there. This is what one of my CPUs looks like in /proc/cpuinfo:

processor       : 0
vendor_id       : GenuineIntel
cpu family      : 6
model           : 23
model name      : Intel(R) Xeon(R) CPU           L5420  @ 2.50GHz
stepping        : 6
cpu MHz         : 2500.087
cache size      : 6144 KB
physical id     : 0
siblings        : 4
core id         : 0
cpu cores       : 4
fpu             : yes
fpu_exception   : yes
cpuid level     : 10
wp              : yes
flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx lm constant_tsc arch_perfmon pebs bts rep_good pni monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr dca sse4_1 lahf_lm
bogomips        : 5003.14
clflush size    : 64
cache_alignment : 64
address sizes   : 38 bits physical, 48 bits virtual
power management:

I know this isn't a laptop, but this box is pulling 190W at idle and 210W under full load; I'm sure it could be lower.

Any ideas?

[InfinityCircuit]

I don't know of any cpufreq support for ANY quads at the moment in the default Ubuntu computers. You may have to just wait.

[jdroflet]

gijs@gijs:~$ ls /sys/devices/system/cpu/cpu0/cpufreq
ls: /sys/devices/system/cpu/cpu0/cpufreq: No such file or directory

same here
Mythbuntu 8.04 Dell Latitude C840

root@ubtop:/# cpufreqd -D
pmu_init : /proc/pmu/info: No such file or directory
apm_init : /proc/apm: No such file or directory
sensors_post_conf : no sensors.conf found, sensors disabled!
plugins_post_conf : Unable to configure plugin sensors_plugin, removing
nforce2_post_conf : Unconfigured, exiting.
plugins_post_conf : Unable to configure plugin nforce2_atxp1, removing
parse_config_profile : Unable to calculate absolute values for profile "Performance High". <etc>

root@ubtop:/# less /etc/cpufreqd.conf
...
[acpi]
acpid_socket=/var/run/acpid.socket
[/acpi]
...

Not much in the cpu0 dir
root@ubtop:/# ls -l /sys/devices/system/cpu/cpu0
total 0
drwxr-xr-x 4 root root 0 2008-09-20 13:19 cpuidle
-r-------- 1 root root 4096 2008-09-20 13:19 crash_notes
drwxr-xr-x 2 root root 0 2008-09-20 13:19 topology

root@ubtop:/# less /proc/cpuinfo
processor : 0
vendor_id : GenuineIntel
cpu family : 15
model : 2
model name : Mobile Intel(R) Pentium(R) 4 - M CPU 1.80GHz
stepping : 7
cpu MHz : 1794.202
cache size : 512 KB
fdiv_bug : no
hlt_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 2
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht
tm pbe up pebs bts sync_rdtsc cid
bogomips : 3592.59
clflush size : 64

Thanks to any who can help.

[edmondt]

I forgot about this, and it a very useful tool to decrease laptop heat when you're on the road

[Skivache]

Excellent post, I wasn't sure my server (an old laptop) was changing the CPU frequency correctly, which it turns out it was. The eggdrop bot I was checking frequency caches the CPU stats (which makes sense..), so a simple rehash solved my problem.

Thanks again for the awesome how-to

[Karpah]

Oh my gosh.... I was searching for a simple solution to my dismal battery life... from ~1.9 hours with wireless/Bluetooth disabled, to ~3 hours with both enabled, just by changing policy_battery to powersave, plus the laptop no longer burns my lap and runs whisper quiet... thank you!!!!

[jhp-dk]

I have a little problem with the scaling. The ondemand daemon is only running at 800mhz or 2ghz even though the processor have more frequencies.

jimmy@jimmy-laptop:~$ cat /sys/devices/system/cpu/cpu*/cpufreq/scaling_available_frequencies
2001000 2000000 1600000 1200000 800000 
2001000 2000000 1600000 1200000 800000

how do i make it scale to other frequencies?