Function sync_cube

pub fn sync_cube()

Coordinates the following among all invocations in the current cube:

• Memory writes to variables in cube address space(shared memory) complete, e.g. writes that were initiated actually land in the cube address space memory.

• Then all the invocations in the cube wait for each other to arrive at the barrier, i.e. this step.

• Then all the invocations int the cube begin executing after the barrier, and all writes to cube address space made before the barrier are now visible to any invocation in this cube.