The vast majority of custom kernels allow various modifications like selecting your governor, adjusting the maximum clock frequency, and much more. These paramters can be changed by executing commands through ADB or by using one of the kernel control applications created by various kernel developers here on XDA.

Applications that let you change kernel settings are often limited to a few basic options or are paid-only. If you are looking for a free app with nice design and a long list of settings to change, XDA Recognized Developer and Contributor Grarak might have something that can come in handy. Kernel Adiutor is an application that manages kernel parameters on rooted devices with Android 4.0 or newer.

This app can adjust the following settings: CPU (Frequency, Governor, Voltages), GPU (Frequency, Governor), Screen (Color Calibration [RGB]), I/O Scheduler, Kernel Samepage Merging, Low Memory Killer (Minfree settings), and Virtual Machine. Settings are also grouped in the nice looking menu in order to prevent the experience from becoming too overwhelming.

Before using this app, please note that setting some values may cause instability to your system or even cause hardware damage. In other words, please use this application with caution.

If your kernel developer hasn't provided an application to control kernel parameters, this app is definitely a nice option to try out. You can download the app or contribute to its development by visiting the Kernel Adiutor application thread.