2

I see no cpufreq performance module:

$ ll /lib/modules/2.6.32-358.2.1.el6.x86_64/kernel/drivers/cpufreq/
total 88<br/>
-rwxr--r--. 1 root root 20576 Mar 12 18:26 cpufreq_conservative.ko
-rwxr--r--. 1 root root 27096 Mar 12 18:26 cpufreq_ondemand.ko
-rwxr--r--. 1 root root  5336 Mar 12 18:26 cpufreq_powersave.ko
-rwxr--r--. 1 root root 14120 Mar 12 18:26 cpufreq_stats.ko
-rwxr--r--. 1 root root 10920 Mar 12 18:26 freq_table.ko

Then, further search online shows that it should be part of the kernel instead of a loadable module (for CentOS 5)?
http://lists.centos.org/pipermail/centos/2010-July/097217.html

I am on CentOS 6 now.

Does it mean that I have to recompile the kernel from source in order to enable cpufreq performance?

Update #1: For some reasons, I don't see the folder (David mentioned) on CentOS 6:

$ ll /sys/devices/system/cpu/cpu0/
total 0<br/>
drwxr-xr-x. 6 root root    0 Mar 14 23:41 cache
drwxr-xr-x. 6 root root    0 Mar 15 01:29 cpuidle
-r--------. 1 root root 4096 Mar 14 23:41 crash_notes
drwxr-xr-x. 2 root root    0 Mar 15 01:29 microcode
lrwxrwxrwx. 1 root root    0 Mar 15 01:29 node0 -> ../../node/node0
drwxr-xr-x. 2 root root    0 Mar 15 01:29 thermal_throttle
drwxr-xr-x. 2 root root    0 Mar 14 23:41 topology

Update #2:

$ sudo cpufreq-set -c 0 -g performance
Error setting new values. Common errors:
- Do you have proper administration rights? (super-user?)
- Is the governor you requested available and modprobed?
- Trying to set an invalid policy?
- Trying to set a specific frequency, but userspace governor is not available,
   for example because of hardware which cannot be set to a specific frequency
   or because the userspace governor isn't loaded?
Hei
  • 21

2 Answers2

2

Even if you see it from command below:

cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_governors

it doesn't mean it's going to work.

It requires that the kernel is compiled with the cpufreq_performance if you're using the performance governor.

The previous comment is not correct about if it lists you can use it, wrong.

You can verify by 

watch grep \"cpu MHz\" /proc/cpuinfo

using sudo of course. If the FREQ changes then you know it's working.

Required - cpufreq_performance.ko module <-- You can check to make sure it exists by running.

First make sure acpi-cpufreq.ko is available.

ls /lib/modules/{kernel version}/kernel/arch/x86/kernel/cpu/cpufreq/

ls /lib/modules/{kernel version}/kernel/drivers/cpufreq/

If the cpufreq_performance.ko module doesn't exist that means you'll need to compile it.

Queasy
  • 21
1

From what I can see (on my Fedora Box), the performance governor is compiled in to the system, so you can just use it.

I am able to check the available governors by using the command 

cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_governors

(And it shows the performance governor even though this is not compiled as a module).

davidgo
  • 73,366