sectors

A warp issues one load instruction and the memory system turns it into some number of 32-byte sector requests; that number is the whole story. The arithmetic for contiguous, stride-2 and stride-32 access, the row-major matrix where a loop order change gives 8x, and the two Nsight Compute counters that show the waste.

Thirty-two addresses per warp instruction, thousands of instructions: say what the pattern is and how many sectors it cost. The address-delta test for contiguous and strided, the sector count that measures the damage, the code that does both, and the edge cases (misalignment, inactive lanes, mixed widths).