[XPERIA X10 Q&A, Help & Troubleshooting] NuriJ:
This was posted by DooMLoRD, i just copied the post ;) not all governors are there:

2. Governors In the Linux Kernel ================================

2.1 Performance ------------------------------

The CPUfreq governor "performance" sets the CPU statically to the highest frequency within the borders of scaling_min_freq and scaling_max_freq.

2.2 Powersave ----------------------------

The CPUfreq governor "powersave" sets the CPU statically to the lowest frequency within the borders of scaling_min_freq and scaling_max_freq.

2.3 Userspace ----------------------------

The CPUfreq governor "userspace" allows the user, or any userspace program running with UID "root", to set the CPU to a specific frequency by making a sysfs file "scaling_setspeed" available in the CPU-device directory.

2.4 Ondemand ---------------------------

The CPUfreq governor "ondemand" sets the CPU depending on the current usage. To do this the CPU must have the capability to switch the frequency very quickly. There are a number of sysfs file accessible parameters:

sampling_rate: measured in uS (10^-6 seconds), this is how often you want the kernel to look at the CPU usage and to make decisions on what to do about the frequency. Typically this is set to values of around '10000' or more.

show_sampling_rate_(min|max): the minimum and maximum sampling rates available that you may set 'sampling_rate' to.

up_threshold: defines what the average CPU usage between the samplings of 'sampling_rate' needs to be for the kernel to make a decision on whether it should increase the frequency. For example when it is set to its default value of '80' it means that between the checking intervals the CPU needs to be on average more than 80% in use to then decide that the CPU frequency needs to be increased.

ignore_nice_load: this parameter takes a value of '0' or '1'. When set to '0' (its default), all processes are counted towards the 'cpu utilisation' value. When set to '1', the processes that are run with a 'nice' value will not count (and thus be ignored) in the overall usage calculation. This is useful if you are running a CPU intensive calculation on your laptop that you do not care how long it takes to complete as you can 'nice' it and prevent it from taking part in the deciding process of whether to increase your CPU frequency.

2.5 Conservative -------------------------------

The CPUfreq governor "conservative", much like the "ondemand" governor, sets the CPU depending on the current usage. It differs in behaviour in that it gracefully increases and decreases the CPU speed rather than jumping to max speed the moment there is any load on the CPU. This behaviour more suitable in a battery powered environment. The governor is tweaked in the same manner as the "ondemand" governor through sysfs with the addition of:

freq_step: this describes what percentage steps the cpu freq should be increased and decreased smoothly by. By default the cpu frequency will increase in 5% chunks of your maximum cpu frequency. You can change this value to anywhere between 0 and 100 where '0' will effectively lock your CPU at a speed regardless of its load whilst '100' will, in theory, make it behave identically to the "ondemand" governor.

down_threshold: same as the 'up_threshold' found for the "ondemand" governor but for the opposite direction. For example when set to its default value of '20' it means that if the CPU usage needs to be below 20% between samples to have the frequency decreased.

2.6 Interactive ------------------------------

The CPUfreq governor "interactive" is designed for low latency, interactive workloads. This governor sets the CPU speed depending on usage, similar to "ondemand" and "conservative" governors. However there is no polling, or 'sample_rate' required to scale the CPU up.

Sampling CPU load every X ms can lead to under powering the CPU for X ms, leading to dropped framerate, stuttering UI etc..

Scaling the CPU up is done when coming out of idle, and like "ondemand" scaling up will always go to MAX, then step down based off of cpu load.

There is only one tuneable value for this governor:

min_sample_time: The ammount of time the CPU must spend (in uS) at the current frequency before scaling DOWN. This is done to more accurately determine the cpu workload and the best speed for that workload. The default is 50ms.

2.7 MinMax ------------------------------

The CPUfreq governor "maxmin" tries to minimize the frequency jumps by limiting the selected frequencies to only two frequencies: either the min or the max frequency of the current policy. The frequency is raised or lowered according to the current load and the 'up_threshold' and 'down_threshold'.

Its parameters and implementation are similar to that of conservative.

It does not have the freq_step parameter as it jumps right from min to max and vice-versa.

The sampling_down_factor, unlike conservative, will count the minimal number of samplings since the last time we saw the 'up_threshold' load on the CPU. Hence it is set to higher default and acts as a limiter not to do too many frequency jumps without hurting the performance.