embedded runtime_error ai_generated true

FreeRTOS: Timer service task overrun, daemon task missed deadline

ID: embedded/freertos-timer-service-task-overrun

Also available as: JSON · Markdown · 中文
88%Fix Rate
83%Confidence
1Evidence
2024-06-20First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
FreeRTOS 10.5.1 active — — —
ESP-IDF 5.1.2 active — — —

Root Cause

Timer service task (daemon) is overloaded with too many active software timers or long callback execution, causing it to miss its scheduling deadline.

generic

中文

定时器服务任务（守护任务）因过多活动软件定时器或回调执行时间过长而过载，导致错过调度截止时间。

Official Documentation

https://www.freertos.org/FreeRTOS-Timer-Service-Task.html

Workarounds

  1. 85% success Reduce number of active timers or move long callbacks to separate tasks. Example: if (xTimerIsTimerActive(xTimer)) { xTimerStop(xTimer, 0); } 
    Reduce number of active timers or move long callbacks to separate tasks. Example: if (xTimerIsTimerActive(xTimer)) { xTimerStop(xTimer, 0); }
  2. 90% success Increase configTIMER_TASK_STACK_DEPTH in FreeRTOSConfig.h to 512 or more to prevent stack overflow, and set configTIMER_QUEUE_LENGTH to 20. 
    Increase configTIMER_TASK_STACK_DEPTH in FreeRTOSConfig.h to 512 or more to prevent stack overflow, and set configTIMER_QUEUE_LENGTH to 20.

中文步骤

  1. Reduce number of active timers or move long callbacks to separate tasks. Example: if (xTimerIsTimerActive(xTimer)) { xTimerStop(xTimer, 0); }
  2. Increase configTIMER_TASK_STACK_DEPTH in FreeRTOSConfig.h to 512 or more to prevent stack overflow, and set configTIMER_QUEUE_LENGTH to 20.

Dead Ends

Common approaches that don't work:

  1. 88% fail

    Increasing timer service task priority does not fix overrun; the issue is CPU time exhaustion, not priority inversion.

  2. 92% fail

    Adding more timer service tasks creates contention and worsens overrun due to scheduler overhead.