DUNE-DAQ / DUNE-DAQ/dpdklibs

[Bug]: Rogue thread activity correlated with opportunistic sleep setting of rx_runner rte-worker threads

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@ShyamB97 is already working on this.

Since Nov 11, 2025.

bug
Dominant language
C++
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Description

Description

Modifying the opportunistic sleep for the rx_runner (link) has a direct impact on some other unnamed threads resource utilization.

Proof with disabled sleep:
Image

On the picture above one see non DPDK rte-worker cores with 100% CPU utilization. Seemingly, one extra core per 100Gb interface.

Steps to reproduce
  1. Take any detector session with Readout applications.
  2. Modify the configuration parameter for the opportunistic sleep in the NICReader configuration.
  3. Boot and configure the system.
  4. Inspect htop to discover the extra 100% polling PIDs.
Version and environment

fddaq-v5.4.3, using ProtoDUNE-VD (np02-session).

Impact

Small/Isolated

Anything else?

Investigate with VTune or other profilers via directly attaching to the particular PIDs to trace down what is executed there.

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First steps

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  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Assessment

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