How to yield on core 0?

[bertmelis]

I've added a task to core 0 on the ESP32. This task has an endless loop. On every iteration I call taskYIELD().

However, the watchdog is still triggered:

E (30547) task_wdt: Task watchdog got triggered. The following tasks did not reset the watchdog in time:
E (30547) task_wdt:  - IDLE (CPU 0)
E (30547) task_wdt: Tasks currently running:
E (30547) task_wdt: CPU 0: mqttclient
E (30547) task_wdt: CPU 1: loopTask
E (30547) task_wdt: Aborting.

When this happens, the task isn't doing anything, the code is skipped and after that it yields using taskYield(). Calling yield() doesn't improve. Calling delay(1) solves the problem.

The code relies on polling WiFiClient so it needs to run on regular intervals as there is no event callback. I suppose 'just yielding' starves the idle task?

[bertmelis]

Found it:

taskYIELD yields to tasks with the same priority or higher. So it doesn't yield to the idle task.
delay(1) and variants block the active task so the idle task can run and feed the watchdog.