ondemand CPUFreq governor not usable in kernel 2.6.38 ?

C00lHandLuke · n00b Joined: 04 Dec 2006 Posts: 26

I've found a lot of conflicting information via various wikis and bug reporting sites regarding the ondemand CPUFreq governor - specifically in kernels >=2.6.38.

It would be extremely helpful to know if anyone running a kernel >=2.6.38 is able to use the ondemand governor.

Even though I have the required modules, I am stuck using the userspace governor with powernowd...

Thanks in advance!

aderesch

C00lHandLuke · n00b Joined: 04 Dec 2006 Posts: 26

I run:
cpufreq-set -c 0 -g ondemand
cpufreq-set -c 1 -g ondemand

However, cpufreq-info results with:
cpufrequtils 007: cpufreq-info (C) Dominik Brodowski 2004-2009
Report errors and bugs to cpufreq@vger.kernel.org, please.
analyzing CPU 0:
driver: p4-clockmod
CPUs which run at the same hardware frequency: 0
CPUs which need to have their frequency coordinated by software: 0
maximum transition latency: 10.00 ms.
hardware limits: 425 MHz - 3.40 GHz
available frequency steps: 425 MHz, 850 MHz, 1.28 GHz, 1.70 GHz, 2.13 GHz, 2.55 GHz, 2.98 GHz, 3.40 GHz
available cpufreq governors: userspace, conservative, ondemand, performance
current policy: frequency should be within 425 MHz and 3.40 GHz.
The governor "performance" may decide which speed to use
within this range.
current CPU frequency is 3.40 GHz (asserted by call to hardware).
cpufreq stats: 425 MHz:0.00%, 850 MHz:0.00%, 1.28 GHz:0.00%, 1.70 GHz:0.00%, 2.13 GHz:0.00%, 2.55 GHz:0.00%, 2.98 GHz:0.00%, 3.40 GHz:100.00%
analyzing CPU 1:
driver: p4-clockmod
CPUs which run at the same hardware frequency: 1
CPUs which need to have their frequency coordinated by software: 1
maximum transition latency: 10.00 ms.
hardware limits: 425 MHz - 3.40 GHz
available frequency steps: 425 MHz, 850 MHz, 1.28 GHz, 1.70 GHz, 2.13 GHz, 2.55 GHz, 2.98 GHz, 3.40 GHz
available cpufreq governors: userspace, conservative, ondemand, performance
current policy: frequency should be within 425 MHz and 3.40 GHz.
The governor "performance" may decide which speed to use
within this range.
current CPU frequency is 3.40 GHz (asserted by call to hardware).
cpufreq stats: 425 MHz:0.00%, 850 MHz:0.00%, 1.28 GHz:0.00%, 1.70 GHz:0.00%, 2.13 GHz:0.00%, 2.55 GHz:0.00%, 2.98 GHz:0.00%, 3.40 GHz:100.00%

I can run the following with the desired output:
cpufreq-set -c 0 -g userspace
cpufreq-set -c 1 -g userspace

Are you running >= 2.6.38 ?

aderesch · Are you running >= 2.6.38 ?

C00lHandLuke · n00b Joined: 04 Dec 2006 Posts: 26

cpufreq-info -g output is:
userspace conservative ondemand performance

It did show the governor available in my previous paste as well. It's compiled into the kernel this time. Previously I compiled it as a module. Either way I end up with an unusable governor. Very weird....

aderesch · Posted: Wed Jul 20, 2011 7:17 pm Post subject:

C00lHandLuke · n00b Joined: 04 Dec 2006 Posts: 26

No exit code at all... It seems I do have the exact same issue with the conservative governor as well. Joy

aderesch · Posted: Wed Jul 20, 2011 7:57 pm Post subject:

DirtyHairy · Posted: Wed Jul 20, 2011 8:38 pm Post subject:

The ondemand governor works for me without any problems, also in 2.6.39 and 3.0.rcx. The frequency scaling can be controlled directly, without any userspace tools in between, via pseudofiles in /sys/devices/system/cpu/cpu[n]/cpufreq (where [n] is the CPU index). Specifically, what are the contents of scaling_available_frequencies, scaling_available_govenors and scaling_governor?

[n00b@localhost] · Posted: Wed Jul 20, 2011 11:24 pm Post subject:

The ondemand governor also works for me under tuxonice-2.6.38-r2.

I am currently having separate issues with cpufreq scaling (although it may be related in some way to the ACPI table parsing problem mentioned above).

C00lHandLuke · n00b Joined: 04 Dec 2006 Posts: 26

/sys/devices/system/cpu/cpu0/cpufreq/ contains:

affected_cpus related_cpus scaling_governor
cpuinfo_cur_freq scaling_available_frequencies scaling_max_freq
cpuinfo_max_freq scaling_available_governors scaling_min_freq
cpuinfo_min_freq scaling_cur_freq scaling_setspeed
cpuinfo_transition_latency scaling_driver stats/

/sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies contains:
425000 850000 1275000 1700000 2125000 2550000 2975000 3400000

/sys/devices/system/cpu/cpu0/cpufreq/scaling_available_governors contains:
userspace conservative ondemand performance

/sys/devices/system/cpu/cpu0/cpufreq/scaling_governor contains:
userspace

cpufreq-set -c 0 -g ondemand ; echo $? outputs:
0

This is a new install of 2.6.38-gentoor6. All of my searching was specifically for this kernel or newer. I do greatly appreciate letting me know it SHOULD function. Therefore, I will continue to dig a bit deeper.

Any and all pointers are appreciated. Maybe it is related to limitations of the latency for setting the frequency? It's interesting the conservative governor is unusable for me as well....

aderesch · Posted: Thu Jul 21, 2011 5:24 am Post subject:

DirtyHairy has a good point, though. You should try setting the governor via

DirtyHairy · Posted: Thu Jul 21, 2011 7:59 am Post subject:

@aderesch: Exactly what I aimed at

If controlling scaling directly via the sysfs files doesn't work either, you can try to change the default governor in the kernel configuration and see what happens.

C00lHandLuke · n00b Joined: 04 Dec 2006 Posts: 26

Yes - In kernel changes result in the same limitations. Really interesting. Maybe understanding if this a Pentium-D limitation would be more specific?

Anyone running a Pentium D using CPUFreq ondemand successfully?

aderesch · Posted: Fri Jul 22, 2011 5:20 am Post subject: