Post breaks down end-to-end CUDA kernel execution
This detailed post traces the lifecycle of a simple vector addition CUDA kernel from its C++ source code to hardware execution on an RTX 4090. It explores compilation via nvcc into PTX and device-specific SASS, the host-to-device bridge facilitated by the CUDA driver involving pushbuffers and GPFIFOs, and the low-level hardware mechanics of the GPU's compute work distributor, instruction caches, and warp schedulers managing resident blocks and hiding memory latency.
This is a masterclass in demystifying the black box of GPU compute.
- –It highlights the "legibility transition", demonstrating that with persistence, the inner workings of closed systems can be deeply understood.
- –By examining PTX versus SASS, the author illustrates the difference between an idealized virtual ISA and the actual hardware execution model.
- –The breakdown of GPU instruction scheduling contrasts sharply with modern CPU dynamic scheduling, emphasizing the fundamental architectural differences between throughput and latency-optimized designs.
DISCOVERED
2h ago
2026-06-29
PUBLISHED
5h ago
2026-06-29
RELEVANCE
AUTHOR
mezark