CUDA Tiled Matrix Multiplication Gets 1.56x Speedup

retr0jirachi · x · 2026-07-17

Day 4 of the CUDA learning series covers tiled matmul.

The core idea is to avoid repeatedly reading the same data from global memory. Instead, you load a tile into shared memory so the entire block can reuse it, minimizing wasteful read/writes.

The author's benchmark results show this implementation runs 1.56x faster than the naive approach on a T4. However, they caution that the L2 cache already masks a lot of waste, so the actual speedup is less dramatic than theory might suggest.

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