3D Integration for Introspection

In today's complex processors, specialized profiling and introspection hardware would be incredibly beneficial to software developers, but most proposals for its addition would increase the cost of every die manufactured. Modular, "snap-on" analysis hardware, stacked vertically with the processor die using a 3D interconnect, could be included with developer systems to assist in debugging and testing, and omitted from consumer systems to keep them economically competitive