[T-Mobile Samsung Galaxy Note II] AndreiLux:
I guess I had to write this some time or another. I just also put this into the main thread.

sampling rate

The default time in-between governor scaling "ticks" where the governor checks CPU load and triggers its scaling logic. Measured in milliseconds (ms).

up threshold

The threshold percentage of load from the last sampling window in which the governor triggers its up-scaling logic.

sampling down factor

If the up-scaling logic reaches the max policy; i.e. the maximum allowed frequency, the governor will disregard all logic for x amount of samples and stay at that frequency until we do another scaling sample.

ignore nice load

Processes with higher priorities can have an augmented reported load value, but we can differentiate this and ignore them if this is checked. Keep it at 0.

io is busy

I/O interaction is seen as a CPU load bearing activity. This isn't true for our architecture so keep it at 0.

down differential

The CPU down-scaling logic threshold is triggered if load is less than (up threshold - down differential). The down differential acts as a buffer so that we don't uselessly scale back up in near threshold level loads. If the down-scaling conditions are met, the CPU will take the current CPU load and derive the next best frequency that would accommodate that frequency without triggering an up threshold.

freq step

When the up-scaling logic is triggered the governor dictates the CPU to raise its frequency by (max policy * (freq step / 100)). If max policy is currently 1600 and freq step 21%, it will scale 1600 * 21% = 336. We have a 100MHz grained frequency table so it rounds up to the next 100MHz, 336 becomes 400. If we're idling at 200MHz and the up-scaling logic gets triggered with the above settings, the next frequency will be 600MHz.

cpu up rate

The amount of samples the hotplug logic will collect before it makes a hotplug decision to bring up a CPU.

cpu down rate

The amount of samples the hotplug logic will collect before it makes a hotplug decision to bring down a CPU.

up nr cpus

If the hotplug logic decides we need to bring CPUs up, the amount of CPUs we bring up at once is being dictated here.

max cpu lock

The maximum allowed amount of CPUs allowed to be up at the same time.

min cpu lock

The minimum allowed amount of CPUs allowed to be up at the same time.

hotplog lock

If set other than 0, locks the CPU up count at the specified amount.

dvfs debug

DVFS and hotplug debug is printed out in /proc/kmsg if this is enabled.

hotplug freq x y

Hotplug frequency threshold which decide if we should trigger a hotplug-up or a hotplug-down. X marks the current amount of cores. Each state has a trigger-down (Y = 0) or a trigger-up (Y = 1) condition.

Example: "hotplug freq 3 0 500000" If there are currently 3 cores up, and the frequency gets below 500MHz and the hotplug rq 3 0 conditions for this state are met too, then bring down the core count to 2.

hotplog rq x y

Similar to the hotplug freq conditions in syntax, only that here we are measuring the amount of threads waiting in the kernel runqueue as opposed to frequency. The kernel runqueue is a queue where threads are waiting to be executed. Every cpu up rate or cpu down rate amount of samples, we accumulate the average snapshots of amount of threads in every sampling window. The value itself is this average, just in integer form multiplied by 100. If set to 175 for example, we need to have at least 1.75 threads running over the last cpu-(up/down)-rate * samples to trigger the condition. Live statistics can be extracted by enabling dvfs_debug to see this.

up threshold at min freq

We have the scaling frequencies divided in two parts: ones governed by up_threshold and ones governed by up_threshold_at_min_freq. We want the CPU to get out of the lower frequency states faster to improve fluidity, and also to improve power consumption as the lower power states are more inefficient in perf/power for fixed load tasks over time. The same logics apply as with up_threshold.

freq for responsiveness

Frequency threshold below which up_threshold_at_min_freq is taken instead of up_threshold.

flexrate enable

Enable flexrate requests. Flexrate requests temporarily dramatically raise the sampling rate / lower the sampling period.

flexrate forcerate

Ignore in-putted values given to the governor and use this instead as the accelerated rate.

flexrate max freq

Frequency threshold above which flexrate requests are ignored.

flexrate num effective usage

A statistic of amount of samples taken at the accelerated rate.

lcdfreq enable

Enable LCD frequency scaling.

lcdfreq kick in down delay

The amount of samples below kick-in-freq the CPU must reside for it to switch to the lower display frequency.

lcdfreq kick in freq

The threshold frequency below the CPU must be for the display to switch to lower display frequency.

And for what it matters, I find Nova Launcher the smoothest of them all.