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arXiv · 2609.11938

Hardware-Attributed Operator Profiling for PyTorch

Logan Chu·Dong Li
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Abstract

Framework profilers expose operator timing without hardware counters; GPU profilers expose hardware counters without operator attribution. Bridging this gap manually is error-prone and does not scale. We present Operator Profiler, a hardware attribution pipeline that automatically links hardware metrics to PyTorch operators via three complementary attribution paths: torch.profiler CUPTI correlation, NVTX temporal enclosure with per-stream interval trees, and Inductor fusion- map enrichment from debug artifacts. NVIDIA Nsight Compute (ncu) hardware counters are matched to NVIDIA Nsight Systems (nsys) kernel records via invocation-order matching, avoiding timestamp joins across incompatible clock domains. A curated 20-counter metric set with duration-weighted aggregation covers all hardware bottleneck axes, layer deduplication reduces ncu replay time by a factor of N/K for models with N layers across K unique structural classes, and GPU clock locking controls the kernel-duration aggregates used for operator-level comparison. On an NVIDIA RTX PRO 6000 Blackwell, Operator Profiler attributes 95-100% of kernel runtime for compiled workloads (GPT-2, SDPA Attention); black-box library backends such as cuDNN RNN are correctly surfaced as greater than 85% unattributed rather than silently dropped. Applied to profile-guided FX graph optimization, attributed profiles yield 1.76x-2.24x profiled-kernel-time speedups on the two compiled optimization case studies; a third LSTM diagnostic case identifies cuDNN re-dispatch as a structural fix rather than an FX graph rewrite.

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Logan Chu, Dong Li. 2026-07-04. Hardware-Attributed Operator Profiling for PyTorch. https://arxiv.org/abs/2609.11938

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