Why start_of_simulation_phase is in bottup manner..?

[Abhi1]

As we know that the start of simulation phase is in bottup up manner but the simulation normallly starts from the top which is nothing but from the test class. So should it not be a top down approach insted of a bottum up approach…?
Can someone kindly justify the above with proper examples.

[dave_59]

You should only rely on the build_phase being top-down. You should assume no predefined ordering of the time-consuming task phases. Assume they get started in parallel

See some of the discussion here:

Calling of build phase?

In reply to georgean: I have attached a small example that demonstrates the calling order for some of the UVM phases given a simple hierarchy. A better term would have been depth-first traversal instead of bottom-up. Note that calling the connect() method is not the same as calling the connect_phase(). The connect() builds a database of connections to be made between components. The order that you call the connect() methods does not matter as long as both ends of the connection have been const…