arXiv Machine Learning

Operator-Aware Mixed-Precision Tolerance Calibration for Tensor Kernels

arXiv:2607. 16228v1 Announce Type: new Abstract: Most tensor-kernel correctness tests go through a fixed-shape all close-style check with hand-picked absolute and relative tolerances.

arXiv Machine Learning
Sep 22

Measuring the Checker: Mutation Analysis for GPU-Kernel Benchmark Oracles

The paper introduces mutation analysis as a metric for evaluating GPU‑kernel benchmark oracles, injecting over ten thousand faults into verified CUDA implementations of 188 KernelBench problems. It shows that the current official checkers miss 16.9% of faults, with precision faults being especially problematic, and demonstrates that optimized test suites can achieve 98% detection with only two inputs per problem. The study also reveals flaws in existing patches and a fuzzing recipe that incorrectly rejects correct kernels 107 times.

By Mingzhe Du, Anh Tuan Luu, Dong Huang, See-Kiong Ng
arXiv Machine Learning
Sep 2

Deterministic LLM Inference Across GPU Kernels: Power-of-Two INT8 Quantization Scales and the Limits of Tolerance-Based Conformance

The paper evaluates the effectiveness of tolerance‑based conformance tests for INT8 quantized GEMM kernels used in large language models. By injecting nine faults into a Qwen3‑1.7B reference pipeline, the authors show that most faults shift outputs by at most one bfloat16 spacing, rendering a tolerance of one spacing blind to these errors. They further demonstrate that requantizing weight scales to the nearest power of two aligns CUTLASS and Triton implementations bit‑for‑bit and produces identical token sequences, with only minor perplexity changes.

By Teng-Ruei Chen
arXiv Machine Learning
Sep 24

Silent Failures Beyond the 32-Bit Index Range: A Differential Characterization of Large-Tensor Matrix Multiplication in PyTorch's MPS Backend

Apple Silicon machines with large unified memory allow large tensors on a desktop GPU, but PyTorch’s Metal Performance Shaders (MPS) backend silently returns incorrect results for batched matrix multiplication when the output exceeds $2^{32}$ elements. The authors swept over dtypes, memory layouts, shapes, and batch sizes around $2^{31}$ and $2^{32}$ elements, finding that errors arise when operands are transposed views or when contiguous inputs exceed $2^{32}$ elements, with the backward pass also affected. They reproduced the issue on multiple machines and macOS versions, confirmed correct behavior on an NVIDIA A100, and demonstrated real‑world impact in a sentiment classifier, releasing a harness and guard to prevent such silent failures.

By Junichiro Niimi
arXiv AI
Sep 17

AutoTuneBench: Trustworthy Measurement for Agent Auto-Tuning of LLM Serving Engines

AutoTuneBench introduces a trustworthy measurement protocol for evaluating how large language model agents auto‑tune GPU kernels and serving engines. The benchmark addresses four failure modes—strawman baselines, machine‑dependent timing, saturated tasks, and infrastructure defects—by enforcing code‑frozen protocols, database validation, anti‑cheat checks, pre‑registered comparisons, and external result anchoring. Using this protocol, the authors demonstrate that previously reported speedups are inflated, revealing more modest improvements across different engines and machines.

By Li Chen