RPI can system operation like rm in a shell have an impact on a Task cycle time

DavidBo
2024-09-23
2024-09-27
  • DavidBo - 2024-09-23

    I have noticed that a rm file1.txt command on a shell has an impact on the cycle time for a TASK writing to file2.txt. Seen in the Monitor fane of the Task configuration
    Furthermore if a TASK makes a system call like rm, its cycle time increases of course but it seems to have an invisible impact on other TASKs too.
    I have a TASK for handling communication over the CANbus (SPI) where it stops sending "Heartbeats" for many seconds when another TASK does a system rm. Why is that not seen on the Monitor fane? Is even codesyscontrol paused when system calls are made?
    The CPU load is about 30-40%

     
  • eschwellinger

    eschwellinger - 2024-09-23

    Which version exactly do you use?

     
  • DavidBo - 2024-09-23

    3.5 18 SP2
    I think the control is 4.2.0.0. I am not in the office before on Wednesday.

     
  • DavidBo - 2024-09-27

    CODESYS Control for Raspberry Pi MC SL v4.4.0.0
    CANopen_Manager 4.2.0.0
    I did not call rm directly from my TASK-i2c, it was trough the attached python script.
    It is not always a problem happens, but sometimes a rm takes a long time.
    I reduced the amount of calls to logi2c.py but I don't understand why TASK-i2c sometimes can cause problems for TASK-CAN

     
  • DavidBo - 2024-09-27

    CODESYS Control for Raspberry Pi MC SL v4.4.0.0
    CANopen_Manager 4.2.0.0
    I did not call rm directly from my TASK-i2c, it was trough the attached python script.
    It is not always a problem happens, but sometimes a rm takes a long time.
    I reduced the amount of calls to logi2c.py but I don't understand why TASK-i2c sometimes can cause problems for TASK-CAN

     

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