Are function calls in Metal Shaders expensive?

Question

I have code that's shared between different compute shaders, located in different #include files. It ranges from custom data types to utility functions.

I'm wondering whether these functions could become a performance issue as the project gets bigger and more of them need to be called?

Are functions automatically inlined when appropriate?

Answer 1

The Metal shader compiler should flatten out all shader code down into one method. You should not need to be concerned about inlining, the more important thing is that your code is constructed to take advantage of parallel processing and coalesced reads and writes.