Benchmark diffuse light

Summary

Benchmark diffuse map computation.

Current behavior

There is no benchmarking.

Desired behavior

(Explain the expected behavior as specifically as possible, with examples, where files should be stored, details on data structure, applications, etc.)

Sources

(Give relevant sources i.e. stackoverflow posts, scientific papers, etc.)

Linked features or branches

(List relevant linked features and branches of the project, typically if this feature request is the child of another branch)