esp32/modesp32: Implement idf_task_stats().

[DvdGiessen]

This adds a new function, esp32.idf_task_stats(), that can be used to retrieve task statistics which is useful for diagnosing issues where some tasks are using up a lot of CPU time. For example, I originally found #8351 and #12728 using this function.

An animated GIF is worth a thousand words:

(See also micropython/micropython-lib#822 which implements the Python function for this.)

By default the functionality is not enabled; it depends on a few extra option to be set. I have the following snippet in my sdkconfig.board files:

# Uncomment to enable esp32.idf_task_stats()
#CONFIG_FREERTOS_USE_TRACE_FACILITY=y
#CONFIG_FREERTOS_VTASKLIST_INCLUDE_COREID=y
#CONFIG_FREERTOS_GENERATE_RUN_TIME_STATS=y

If the required FreeRTOS functionality is available, the idf_task_stats() function is automatically enabled.

[dpgeorge]

This looks pretty neat! The zephyr port already has zephyr.thread_analyze() which I think just dumps all tasks, but what you have here is more useful.

I think this would be a good (optional) addition.

[DvdGiessen]

Thank you for the feedback! I've updated the branch to address them.

One thing I'm not sure about is the rather large code snippet (compared to snippets elsewhere in the documentation) that implements the print_task_stats() function. I suppose is a useful example, but not sure this is the right place for it. Though it is easily discoverable this way.

[dpgeorge]

One thing I'm not sure about is the rather large code snippet (compared to snippets elsewhere in the documentation) that implements the print_task_stats() function. I suppose is a useful example, but not sure this is the right place for it

It could be added to examples/... in this repo. But maybe it could make sense to put it in micropython-lib as an esp32 tool? Easy to install it then on a board.

[DvdGiessen]

Updated to move the code snippet from the documentation to a separate function in micropython-lib: micropython/micropython-lib#822