Scheduler get full by NRF_EVT_RADIO_BLOCKED events during connect.

[bart]

Using:

• nRF52832
• SDK 15.3.0
• SD S132 6.1.1
• nRF5 SDK for Mesh 3.2.0
• NRF_SDH_DISPATCH_MODEL == NRF_SDH_DISPATCH_MODEL_APPSH

Hi, I'm often getting a crash when connecting. The back trace showed hints of it happening in the mesh code: timeslot.c handling event NRF_EVT_RADIO_BLOCKED.

But later I found out it actually happens because the app scheduler is full, while nrf_sdh.c tries to add a SD event on the scheduler: ret_code_t ret_code = app_sched_event_put(NULL, 0, appsh_events_poll);

When logging SOC events, I noticed many NRF_EVT_RADIO_BLOCKED events coming in when a connection is made. And when inspecting what happens, I saw that timeslot.c simply keeps on requesting a new timeslot until it succeeded.

Am I right to assume this timeslot request loop can lead to the scheduler getting filled up (especially when other processes also add to the scheduler)? And if so, is there a solution for this?

[Mttrinh]

Hi,

Am I right to assume this timeslot request loop can lead to the scheduler getting filled up (especially when other processes also add to the scheduler)?

Yes, I think that can be the case.

When logging SOC events, I noticed many NRF_EVT_RADIO_BLOCKED events coming in when a connection is made.

Not sure what you mean by connect? Assuming your application are only running ble mesh, there is no concept of connections in a mesh network.

Could you provide more information regarding your use-case and what you are trying to do?

Could it be related to interrupt priority levels?

Also, is there a reason you are using an old SDK version? If possible I would suggest you move to our latest SDK(nRF5 for Mesh SDK v5.0.0), as many improvements have been made from v3.2.0 to v.5.0.0.

[Mttrinh]

Hi,

This have been sent to our Mesh team to have look at, I will update you once I have a response from them.

[bart]

Thanks, looking forward to it.

For now I'm using a work around to at least not crash: patch

When just using that work around, however, we get even more calls to sd_radio_request(), causing the main thread to be blocked until the connect succeeded.

To avoid that, I now also wait for NRF_MESH_EVT_DISABLED before calling sd_ble_gap_connect(). This prevents most of the NRF_EVT_RADIO_BLOCKED loops.

Handling NRF_EVT_RADIO_SESSION_CLOSED still takes 4 ms while connecting. And there are still some short NRF_EVT_RADIO_BLOCKED loops, mostly while connected, but they don't block the main thread for seconds, still can take up to 15 ms to handle.