Use workpiece and frame identifiers to link triggers, image arrival at the application, queue entry, inference start and end, and workflow decisions. Queue entry to inference start can measure queuing delay. Measure inference between its own start and end. Use matching events at sender and receiver to measure transfer delay.
Check the event behind each timestamp
Linux V4L2 buffer flags can identify the clock type and the capture event for a timestamp. Check the actual driver output. For measurements across devices, verify clock synchronization and error, or record both events with one measuring device. Record trigger and exposure separately, and distinguish arrival from queue exit. See the kernel buffer documentation.
Follow the same workpiece through the critical path
Keep records of retries, dropped frames, timeouts and missing confirmations. When operations overlap, check the time between the relevant start and end events for the same workpiece. Compute percentiles for each stage separately. Compute end-to-end percentiles from measured end-to-end times for individual workpieces.
Related service: Vision algorithms and model engineering.