I am pretty obsessed with getting every little bit of performance I can out of my code, especially when developing for mobile platforms. For loops, believe it or not, can be optimized using some very simple tricks. Normally you probably write a for loop like this:
for (int i = 0; i < some.Length; i++) {
// Code
}
If you know that the length of whatever you're iterating is going to be less than 256 (0-255) you can use byte instead of int, if you aren't completely certain, you can probably get away with ushort (0-65,535). This will free up 24 and 16 bits as compared to int respectively, it's not much, but it can add up. You can also pre-lock the length into a variable to help speed things up. The reason this works is because for loop check their condition (second block) every single iteration. This means that you are accessing the length property every single iteration. Accessing a member of a class is more expensive than accessing a single variable, and thus adds up over many iterations. The performance change might be slight, but it adds up pretty quickly, especially if you are iterating through hundreds of pieces of data every single frame. So, what should the for loop look like? Well, like this:
byte length = some.Length;
for (byte i = 0; i < length; i++) {
// Code
}
