L Speed is a popular tweaking application for Android that offers tweaks to improve the performance and battery life of your Android device.
The advanced nature of the tweaks makes root access a necessity. While you can install the app on any device running Android 4.0 and up, tweaks become only available after root permissions have been granted to L Speed.
The app displays information about the battery, memory, the process and kernel on start but those are not all that useful unless you are a developer or deeply interested in metrics such as the exact kernel identifier or the mapped memory.
That's not to say that you won't find some information useful, for instance the battery temperature and health, or how much memory hidden apps use.
Note: L Speed makes changes to core Android preferences. It is suggested to create a backup of your data before you star using the app.
A tap on the menu icon displays tweak categories that you can dive in. A good starting point is the main tweaks category which lists several pages worth of tweaks when it is loaded.
You can use quick tools listed at the top to free memory, run FSTRIM or calibrate the battery, or adjust listed preferences as you see fit.
The author lists a recommended setup on the apps' page on Google Play, but an option to enable with a single tap in the app itself is not provided currently.
This means that you will have to go through the list of tweaks manually to adjust preferences while you do so.
While you may be able to do so directly for several of the tweaks listed, it may sometimes be difficult to understand what a preference does under the hood or at all.
Since you have got only tweak names for that, you may need to research certain tweaks to understand what they do.
This is for instance the case for "flag turner", "misc tweaks", or " disable kernel panic" which are all listed on the main tweaks page.
A good starting point for that is the official thread on the XDA Developers website where you find information about individual tweaks.
The "Disable kernel panic" tweak for instance blocks the operating system from writing debug info or rebooting the system if the kernel detects and error from which it cannot recover.
Main tweaks is just one of the many tweak groups L Speed makes available. You find IO Tweaks, Net optimization tweaks, or a CPU tuner listed there as well.
Those groups don't throw dozens of tweaks at you however but they are worth a visit, especially if you want your device to improve in one of those categories.
The LNET Optimizer listing for instance allows you to enable Google DNS servers, faster streaming, or fast dormancy, and even adjust the NET buffers (default, small, big).
An option to reset all settings to their default values is provided as well.
L Speed has been designed specifically for Android devices that drain battery like crazy, lag, or offer bad performance. While you can use it on a pristine fast device as well, you will probably won't notice much of a difference when you do.
Your mileage may vary depending on the changes you make when using the app, and your device.