Discussion on "Busy polling or events ? Timing one RDMA write, and why perftest says half"

Nathanael FETUE · 2026-11-09T05:27:45.152Z

Building AgentXDP, part 13. Part 12 gave the testbed four links. This part gives it a stopwatch. In part 6, 20 ms of ACK delay left every RDMA error counter at zero. A delay shows up in one place: how

The distinction between CQ completion and remote delivery makes the perftest comparison much clearer. One reproducibility detail that could help interpret the 7.7 µs event-vs-poll median delta is whether the submitting thread and IRQ/NIC processing were CPU-pinned; even on Soft-RoCE, scheduler placement can shift that wake-up cost. Your caveat about the three-vCPU VM and noisy maxima already points to why it matters.

Busy polling or events ? Timing one RDMA write, and why perftest says half

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Busy polling or events ? Timing one RDMA write, and why perftest says half

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