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Show HN: Deterministic PCIe Diagnostics for GPUs on Linux

gpu_systems Tuesday, December 16, 2025

I built a small Linux tool to deterministically verify GPU PCIe link health and bandwidth.

It reports: - Negotiated PCIe generation and width - Peak Host→Device and Device→Host memcpy bandwidth - Sustained PCIe TX/RX utilization via NVML - A rule-based verdict derived from observable hardware data only

This exists because PCIe issues (Gen downgrades, reduced lane width, risers, bifurcation) are often invisible at the application layer and can’t be fixed by kernel tuning or async overlap.

Linux-only: it relies on sysfs and PCIe AER exposure that Windows does not provide.

Summary
This article describes a tool for diagnosing and troubleshooting issues with GPU-PCIe connectivity, including identifying bottlenecks, thermal throttling, and other performance-related problems. The tool provides detailed insights into the system's GPU-PCIe configuration, enabling users to optimize their hardware setup for maximum performance.
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