Default Limit Global Framerate

I would like to offer users of a ROM the ability to set their own global, system frame rate limit. For example, if a user wants to save a lot of battery, they could set the limit to 30FPS, but if someone wanted performance, they could increase it to 80FPS.

Where should I look for the ability to do this? There are many threads discussing removing limits but none about setting them.

TIA