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<== Date ==> <== Thread ==>

Subject: Handling Polling and CPU Bottleneck for Large Image Capture in areaDetector
From: "Kim, Kuktae via Tech-talk" <tech-talk at aps.anl.gov>
To: tech-talk <tech-talk at aps.anl.gov>
Date: Mon, 28 Apr 2025 15:00:00 +0000
Hello,

We are developing an areaDetector IOC for a large sensor camera (6144 x 6144, 16-bit depth, ~75 MB per image) and would like some advice on a few issues:

  1. Polling Impact:
    We set up Polling features (ReadStatus.SCAN) so users can monitor sensor and device temperatures for interlocks. However, polling seems to block other tasks and lowers the image capture rate from ~12 Hz to ~7 Hz.
    We added the SCAN field of GC_SensorTemperature and GC_DeviceTemperature records as SCAN = "1 second", but now get warnings like "GC_SensorTemperature is not writable" in the IOC shell.
    Could you advise us on how to properly handle this situation?

  2. CPU Bottleneck:
    According to the manual, the camera can capture ~11 Hz (standard mode) and ~26 Hz (high-speed mode). We currently reach up to ~13 Hz, but plugin threads are hitting 99.9% CPU usage.
    Is there a way to use multithreading for plugins to reduce CPU load and increase the capture rate?

Photos are attached for reference:

< CPU Bottleneck: Some plugin threads reach up to 99.9% CPU usage, limiting the capture rate >

< Polling Impact: Polling causes overall CPU usage to decrease and lowers image capture performance >

Thank you for your help!

Best regards,
Kuktae






Replies:
RE: Handling Polling and CPU Bottleneck for Large Image Capture in areaDetector Mark Rivers via Tech-talk

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