Deep Profile

Ordinary profiling will only record the time and memory allocations made by common Unity callback methods, such as Awake(), Start(), Update(), and FixedUpdate(). Enabling the Deep Profile option recompiles our scripts with a much deeper level of instrumentation, allowing it to measure each and every invoked method. This causes a significantly greater instrumentation cost during runtime than normal, and uses substantially more memory since data is being collected for the entire callstack at runtime. As a consequence, deep profiling may not even be possible in large projects, as Unity may run out of memory before testing even begins, or the application may run so slowly as to make the test pointless.

Since this option blindly measures the entire callstack, it would be unwise to keep it enabled during most of our profiling tests. This option is best reserved for when default profiling does not provide sufficient detail to figure out the root cause, or if we're testing the performance of a small test scene, which we're using to isolate certain activities.

If deep profiling is required for larger projects and scenes, but the Deep Profile option is too much of a hindrance during runtime, then there are alternative approaches that can be used to perform more detailed profiling; see the upcoming section entitled Targeted profiling of code segments.