Kernel: CPUFreq Governors

1.) What is it? 

A CPUFreq Governors is a driver for regulate CPUFreq (CPU-Frequency). As the name suggests us, is the Governor something like a decider, when at full capacity, the maxFreq – maximum frequency – is achieved or how quickly the minFreq – minimum frequency – or center frequency is achieved. He shall decide when, how and how long will the CPU will respond and still save battery and still continue to operate smoothly.

There are very many types of Governors. Some are designed for have better battery-time or better performance … so select a governor based upon your workload.

 

2.) What “Governors” are there?

conservative – Increases frequency step by step, decreases instantly

ondemand – Uses a high CPU frequency when tasks are started, decreases step by step

performance – CPU only runs at max frequency regardless of load

powersave – CPU only runs at min frequency regardless of load (only scaling min frequency is too low for us).

[… need more work here …]

 

3.) “Governors”-Settings 

[… need more work here …]

[cc lang=’bash’ ]

ls -al /sys/devices/system/cpu/cpu*/cpufreq/

-rwxrwxrwx 1 root system 4096 Sep 22 03:15 UV_mV_table
-rwxrwxrwx 1 root system 4096 Sep 22 03:15 affected_cpus
-rwxrwxrwx 1 root system 4096 Sep 22 03:15 cpuinfo_cur_freq
-rwxrwxrwx 1 root system 4096 Sep 22 03:15 cpuinfo_max_freq
-rwxrwxrwx 1 root system 4096 Sep 22 03:15 cpuinfo_min_freq
-rwxrwxrwx 1 root system 4096 Sep 22 03:15 cpuinfo_transition_latency
-rwxrwxrwx 1 root system 4096 Sep 22 03:15 related_cpus
-rwxrwxrwx 1 root system 4096 Sep 22 04:01 scaling_available_frequencies
-rwxrwxrwx 1 root system 4096 Sep 22 03:15 scaling_available_governors
-rwxrwxrwx 1 root system 4096 Sep 22 03:15 scaling_cur_freq
-rwxrwxrwx 1 root system 4096 Sep 22 03:15 scaling_driver
-rwxrwxrwx 1 root system 4096 Sep 22 04:01 scaling_governor
-rwxrwxrwx 1 root system 4096 Sep 22 04:01 scaling_max_freq
-rwxrwxrwx 1 root system 4096 Sep 22 03:15 scaling_max_suspend_freq
-rwxrwxrwx 1 root system 4096 Sep 22 04:34 scaling_min_freq
-rwxrwxrwx 1 root system 4096 Sep 22 03:15 scaling_min_suspend_freq
-rwxrwxrwx 1 root system 4096 Sep 22 03:15 scaling_setspeed
-rwxrwxrwx 1 root system 4096 Sep 22 03:15 smooth_level
drwxrwxrwx 2 root system 0 Sep 22 03:15 stats
-rwxrwxrwx 1 root system 4096 Sep 22 03:15 vdd_levels

[/cc]

 

 

more Info:

– The CPUFreq governors -> http://publib.boulder.ibm.com/infocenter/lnxinfo/v3r0m0/index.jsp?topic=%2Fliaai%2Fcpufreq%2FTheCPUFreqGovernors.htm

– Kernel Governors, Modules, I/O Schedulers, CPU Tweaks, AIO App Configs -> http://forum.xda-developers.com/showthread.php?t=1369817&styleid=16