3 months ago
- The article discusses the necessity of hardware-based validation for instruction schedules in deep-pipeline GPUs like the NVIDIA B200, as static analysis alone is insufficient and can lead to silent correctness bugs due to under-stalling.
- It highlights specific pipeline hazards, including predicate-consumer under-stalls where a branch reads a stale predicate value, and fixed-latency RAW under-stalls in operations like FFMA and DFMA, emphasizing the need for precise latency measurements through on-silicon probing.
- The article explains variable-latency operations (e.g., LDG, LDS) that rely on scoreboard mechanisms for dependency tracking, and proposes crash-amplified load-use hazards as a method for deterministic failure detection in CI systems.
- It stresses that compiler engineers must rely on silicon as the ultimate arbiter of correctness, advocating for systematic hardware hazard registries and reproducible on-silicon tests to validate scheduling logic against pipeline realities.