Arch Linux

apearson

Member

Registered: 2010-08-08

Posts: 3

CPU Frequency Scaling Problem

Hey all,

I'm new to Arch Linux but not to Linux in general.  I'm having a rather interesting issue with using cpufrequtils and laptop mode tools.  The problem is, when I unplug my laptop, my CPU is using the "performance" governor instead of the "ondemand" governor which I specify in /etc/laptop-mode/conf.d/cpufreq.conf.  I know this because when I type:
cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
I get:
performance

If I do /etc/rc.d/laptop-mode restart while my battery is still unplugged, the governor will switch to "ondemand" like it is supposed to.  Anyone have any ideas why this might be happening?  Thank you very much.

apearson

Member

Registered: 2010-08-08

Posts: 3

Re: CPU Frequency Scaling Problem

Additionally, if I boot up the computer with the AC unplugged, it will have the proper "ondemand" governor.  Is something not getting triggered at the right time?  Please let me know if there is any other information that I can give to make this problem easier to solve.  Thanks again!

lagagnon

Member

From: an Island in the Pacific...

Registered: 2009-12-10

Posts: 1,087

Website

Re: CPU Frequency Scaling Problem

The only thing I can think of is that there is something funny in your /etc/acpi/actions and/or /etc/acpi/events scripts which are messing with the governor when you are on/off ac-power. Check out those scripts.

---

Philosophy is looking for a black cat in a dark room. Metaphysics is looking for a black cat in a dark room that isn't there. Religion is looking for a black cat in a dark room that isn't there and shouting "I found it!". Science is looking for a black cat in a dark room with a flashlight.

apearson

Member

Registered: 2010-08-08

Posts: 3

Re: CPU Frequency Scaling Problem

Will do, and I will post what I find.  Additionally, I think I might write up a tutorial for getting my new Arrandale laptop up and running on Arch with pretty good battery life.  I was working on optimizing it for less than a day and already have it averaging from 11-14 watts on battery.

ewaller

Administrator

From: Pasadena, CA

Registered: 2009-07-13

Posts: 19,793

Re: CPU Frequency Scaling Problem

There are a couple ways to configure your system to respond to changes in power state.  Some of the fully integrated desktop environments (Gnome, KDE) include power management monitoring and control.  The other is ACPI (as implied by lagagnon)

You did not state whether you are running something like KDE (with powerdevil) or whether you are intending to use lower level stuff like acpid.  Setting up power management by the DEs is fairly straightforward using the GUIs.  I generally prefer to use acpid in lieu of the DEs.

Note: if you are planning for the aforementioned acpi scripts to work, make sure you have started your acpid daemon

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barzam

Member

From: Sweden

Registered: 2009-01-27

Posts: 277

Re: CPU Frequency Scaling Problem

Are you running the cpufreq daemon? See the wiki on cpufrequtils. I think laptop mode tools is the worse way to handle cpu frequency and the ondemand profile controlled by the cpufrequtils daemon much better!

JamieKitson

Member

From: UK

Registered: 2010-10-18

Posts: 161

Website

Re: CPU Frequency Scaling Problem

I found that I had to install and run the daemon acpid to get this working.

Hope that helps someone save the time that I spent looking into it.

fowler

Member

Registered: 2009-01-26

Posts: 152

Re: CPU Frequency Scaling Problem

I have cpufreq installed as well as laptop-mode and acpid.  I am not using laptop-mode to manage cpu scaling as I opted for cpufreq to do that after laptop-mode wasn't working.  Well it turns out that neither is cpufreq.  I am unable to change my frequency to whatever I want (I can change the governor but I'm not sure that is working either).  Furthermore on the 'Ondemand' setting I have never seen the frequency jump even when I'm taxing the crap out of the cpu.  Also suspend/hibernate work.  I have a Dell Latitude E5510 if that helps (not too impressed with this thing).  It has a celeron p4500.

cat /proc/cpuinfo
processor    : 0
vendor_id    : GenuineIntel
cpu family    : 6
model        : 37
model name    : Intel(R) Celeron(R) CPU        P4500  @ 1.87GHz
stepping    : 2
cpu MHz        : 933.000
cache size    : 2048 KB
physical id    : 0
siblings    : 2
core id        : 0
cpu cores    : 2
apicid        : 0
initial apicid    : 0
fpu        : yes
fpu_exception    : yes
cpuid level    : 11
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 rdtscp lm constant_tsc arch_perfmon pebs bts rep_good xtopology nonstop_tsc aperfmperf pni dtes64 monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr pdcm popcnt lahf_lm arat dts tpr_shadow vnmi flexpriority ept vpid
bogomips    : 3725.09
clflush size    : 64
cache_alignment    : 64
address sizes    : 36 bits physical, 48 bits virtual
power management:

lspci output:
00:00.0 Host bridge: Intel Corporation Core Processor DRAM Controller (rev 02)
00:02.0 VGA compatible controller: Intel Corporation Core Processor Integrated Graphics Controller (rev 02)
00:16.0 Communication controller: Intel Corporation 5 Series/3400 Series Chipset HECI Controller (rev 06)
00:1a.0 USB Controller: Intel Corporation 5 Series/3400 Series Chipset USB2 Enhanced Host Controller (rev 05)
00:1b.0 Audio device: Intel Corporation 5 Series/3400 Series Chipset High Definition Audio (rev 05)
00:1c.0 PCI bridge: Intel Corporation 5 Series/3400 Series Chipset PCI Express Root Port 1 (rev 05)
00:1c.1 PCI bridge: Intel Corporation 5 Series/3400 Series Chipset PCI Express Root Port 2 (rev 05)
00:1c.2 PCI bridge: Intel Corporation 5 Series/3400 Series Chipset PCI Express Root Port 3 (rev 05)
00:1c.3 PCI bridge: Intel Corporation 5 Series/3400 Series Chipset PCI Express Root Port 4 (rev 05)
00:1c.5 PCI bridge: Intel Corporation 5 Series/3400 Series Chipset PCI Express Root Port 6 (rev 05)
00:1d.0 USB Controller: Intel Corporation 5 Series/3400 Series Chipset USB2 Enhanced Host Controller (rev 05)
00:1e.0 PCI bridge: Intel Corporation 82801 Mobile PCI Bridge (rev a5)
00:1f.0 ISA bridge: Intel Corporation Mobile 5 Series Chipset LPC Interface Controller (rev 05)
00:1f.2 SATA controller: Intel Corporation 5 Series/3400 Series Chipset 4 port SATA AHCI Controller (rev 05)
00:1f.3 SMBus: Intel Corporation 5 Series/3400 Series Chipset SMBus Controller (rev 05)
00:1f.6 Signal processing controller: Intel Corporation 5 Series/3400 Series Chipset Thermal Subsystem (rev 05)
02:00.0 Network controller: Broadcom Corporation BCM4313 802.11b/g/n Wireless LAN Controller (rev 01)
03:00.0 SD Host controller: Ricoh Co Ltd MMC/SD Host Controller (rev 03)
03:00.4 FireWire (IEEE 1394): Ricoh Co Ltd FireWire Host Controller (rev 03)
0b:00.0 Ethernet controller: Broadcom Corporation NetXtreme BCM5761e Gigabit Ethernet PCIe (rev 10)
3f:00.0 Host bridge: Intel Corporation Core Processor QuickPath Architecture Generic Non-core Registers (rev 02)
3f:00.1 Host bridge: Intel Corporation Core Processor QuickPath Architecture System Address Decoder (rev 02)
3f:02.0 Host bridge: Intel Corporation Core Processor QPI Link 0 (rev 02)
3f:02.1 Host bridge: Intel Corporation Core Processor QPI Physical 0 (rev 02)
3f:02.2 Host bridge: Intel Corporation Core Processor Reserved (rev 02)
3f:02.3 Host bridge: Intel Corporation Core Processor Reserved (rev 02)

Last edited by fowler (2011-01-09 20:09:00)

fowler

Member

Registered: 2009-01-26

Posts: 152

Re: CPU Frequency Scaling Problem

Never mind... my bonehead sister accidentally swapped my power supply with her HP power supply... all is fine.