Visually it is the same as the execution time implemented for the
geometry nodes, and it is to be enabled in the overlay popover.
The implementation is separate from the geometry nodes, as it is
not easy or practical to re-use the geometry nodes implementation.
The execution time is stored in a run-time hash, indexed by a node
instance key. This is similar to the storage of the mode preview
images, but is stored on the scene runtime data and not on the node
tree. Indexing the storage by key allows to easily copy execution
statistics from localized tree to its original version.
The time is only implemented for full-frame compositor, as for the
tiled compositor it could be tricky to calculate reliable time for
pixel processing nodes which process one pixel at a time.
Pull Request: https://projects.blender.org/blender/blender/pulls/117885
467a132166