Task Watchdog is causing the device to slow down

RE: Task Watchdog is causing the device to slow down

Giannis Anastasopoulos — Thu, 13 Jan 2022 14:31:27 GMT

Dear Håkon Alseth

Your suggested change indeed solved the issue, combined with the fix that I had originally included, so now it seems that it works as expected. Thank you very much for your assistance

RE: Task Watchdog is causing the device to slow down

Håkon Alseth — Thu, 13 Jan 2022 12:10:32 GMT

Hi,

Thank you very much for the project. I was able to reproduce the issue, and it seems to be related to the logic in task_wdt.c. If I manually apply this commit, the print is acting as normal:

https://github.com/nrfconnect/sdk-zephyr/commit/df1125a58c8a313b6518ef44054d6c25f37e15a4

Could you try this and see if you see the same behavior?

Kind regards,

Håkon

RE: Task Watchdog is causing the device to slow down

Giannis Anastasopoulos — Wed, 12 Jan 2022 16:31:12 GMT

Dear Håkon Alseth

I have created the following project that includes all the prj.conf of my overall project, but the functionality is limited to demo the issue that I am dealing with.

I have used the commands:

west build -p auto -b nrf9160dk_nrf9160ns

and

west flash.
devzone.nordicsemi.com/.../test_5F00_code.rar

Thanks again for your assistance.

RE: Task Watchdog is causing the device to slow down

Håkon Alseth — Wed, 12 Jan 2022 14:36:19 GMT

Hi,

Do you have a minimal sample that reproduces the error that you can share with me?

Kind regards,

Håkon

RE: Task Watchdog is causing the device to slow down

Giannis Anastasopoulos — Wed, 12 Jan 2022 13:33:43 GMT

Håkon Alseth

Thank you very much for assisting me.

"UART or RTT? LOG or printk?"

Both printk and LOG are hanging.

On top of this, I have created a sample where the CONFIG_TASK_WDT_HW_FALLBACK is not enabled and I am not feeding the watchdog, so once the timer expires, instead of calling my callback the device seems to behave the same as when I had the hardware fallback enabled.

Do you do LOG_MODE_MINIMAL or have a dedicated logging thread?

I have CONFIG_LOG_MODE_MINIMAL set to n. Since the slow printing comes from the printk as well, then I think that the problem is affecting the main thread.

I am not sure if you have enough to understand/reproduce the issue here.

RE: Task Watchdog is causing the device to slow down

Håkon Alseth — Wed, 12 Jan 2022 13:16:35 GMT

Hi,

[quote user=""]

I have dealt with several issues, one of them being the issue resolved here:
https://github.com/zephyrproject-rtos/zephyr/issues/39523

After applying the above fix, my device would not hard-fault

[/quote]

I am glad this unblocked you, atleast from a fault situation!

[quote user=""]The debug messages that I am using would start to be printed at a gradually slower pace until they almost stop and the device will just remain in that state.[/quote]

Could you share a bit more information on this matter?

UART or RTT? LOG or printk?

Do you do LOG_MODE_MINIMAL or have a dedicated logging thread?

[quote user=""]I am not sure what exactly is the issue but, when I set the CONFIG_TASK_WDT_HW_FALLBACK, the device behaves normally again.[/quote]

Given the description and behavior of enabling this configuration, it seems that there's a thread hanging:

https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/kconfig/CONFIG_TASK_WDT_HW_FALLBACK.html#std-kconfig-CONFIG_TASK_WDT_HW_FALLBACK

Kind regards,

Håkon