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neonkernel
confirmedC++ · NEON / Apple M4Systems & data structuresJuly 6, 2026
the question
For a quantized decode GEMV, how much does a hand-written NEON kernel buy, and what does it cost in accuracy?
what came out
int8 SDOT is the dominant throughput lever -- >=3x the best f32 kernel -- at a cost of <1% accuracy (0.045% relative-L2 vs an f64 reference). Hand-NEON f32 is 3.1x the scalar loop, but for int8 the hand-SDOT kernel is only 1.46x scalar: the compiler already vectorizes int8 well. Standalone C++ ARM NEON, bit-reproducible.
method & receipts
- Result: confirmed
- Pre-registered — the prediction was written down and committed before the run.
- Reproducible — one script re-runs the whole thing from scratch.
- Independently reviewed — an adversarial review pass, kept in the repo.
- Machine-readable claims — every reported number, in a checkable file.
- Tested — a correctness/benchmark suite ships alongside the code.
→ read the code and re-run it
github.com/v-code01/neonkernel