modules: memfault: Update Bluetooth stack metrics

Zephyr 3.7.0 changed the 2 threads being tracked:

- `BT RX` thread was renamed to `BT RX WQ`:
  zephyrproject-rtos/zephyr@5591d23
- `BT TX` thread was removed, TX ops now run on sysworkq

Update the `ncs_bt_rx_unused_stack` metric to track the `BT RX WQ`
thread.

Remove the `ncs_bt_tx_unused_stack` metric.

Add a new metric, `ncs_bt_lw_wq_unused_stack`, to track the `BT LW WQ`
thread stack usage.

To test:

Build a sample like so:

❯ west build --board nrf54l15dk/nrf54l15/cpuapp \
  --pristine=always zephyr/samples/bluetooth/peripheral_hr \
  -- \
  -DCONFIG_SHELL=y \
  -DCONFIG_MEMFAULT=y \
  -DCONFIG_MEMFAULT_DEVICE_INFO_CUSTOM=y \
  -DCONFIG_HWINFO=y \
  -DCONFIG_BT_SHELL=y \
  -DCONFIG_MEMFAULT_NCS_FW_TYPE=\"app\" \
  -DCONFIG_MEMFAULT_NCS_DEVICE_ID=\"testserial\" \
  -DCONFIG_MEMFAULT_NCS_BT_METRICS=y \
  -DCONFIG_MEMFAULT_NCS_STACK_METRICS=y

Trigger a heartbeat using shell commands, and do the usual
upload-symbol-file-and-upload-chunks dance to push the data into
Memfault, and confirm it decodes correctly:

uart:~$ mflt test heartbeat
Triggering Heartbeat
uart:~$ mflt export
<chunks follow>

Decoded heartbeat metrics:

      "ncs_bt_rx_unused_stack": 2952,
      "ncs_bt_lw_wq_unused_stack": 848,

Signed-off-by: Noah Pendleton <[email protected]>

Author: noahp

doc/nrf/releases_and_maturity/releases/release-notes-changelog.rst

@@ -760,6 +760,12 @@ Memfault integration
   * The ``CONFIG_MEMFAULT_DEVICE_INFO_CUSTOM`` Kconfig option has been renamed to :kconfig:option:`CONFIG_MEMFAULT_NCS_DEVICE_INFO_CUSTOM`.
   * The ``CONFIG_MEMFAULT_DEVICE_INFO_BUILTIN`` Kconfig option has been renamed to :kconfig:option:`CONFIG_MEMFAULT_NCS_DEVICE_INFO_BUILTIN`.
 
+* Added a metric tracking the unused stack space of the Bluetooth Long workqueue thread, when the :kconfig:option:`CONFIG_MEMFAULT_NCS_BT_METRICS` Kconfig option is enabled.
+  The new metric is named ``ncs_bt_lw_wq_unused_stack``.
+
+* Removed a metric for the tracking Bluetooth TX thread unused stack ``ncs_bt_tx_unused_stack``.
+  The thread in question was removed in Zephyr v3.7.0.
+
 AVSystem integration
 --------------------
 

modules/memfault-firmware-sdk/config/memfault_metrics_heartbeat_extra.def

@@ -7,7 +7,7 @@
 #ifdef CONFIG_MEMFAULT_NCS_STACK_METRICS
 MEMFAULT_METRICS_KEY_DEFINE(ncs_connection_poll_unused_stack, kMemfaultMetricType_Unsigned)
 MEMFAULT_METRICS_KEY_DEFINE(ncs_bt_rx_unused_stack, kMemfaultMetricType_Unsigned)
-MEMFAULT_METRICS_KEY_DEFINE(ncs_bt_tx_unused_stack, kMemfaultMetricType_Unsigned)
+MEMFAULT_METRICS_KEY_DEFINE(ncs_bt_lw_wq_unused_stack, kMemfaultMetricType_Unsigned)
 #endif /* CONFIG_MEMFAULT_NCS_STACK_METRICS */
 
 #ifdef CONFIG_MEMFAULT_NCS_LTE_METRICS

modules/memfault-firmware-sdk/memfault_bt_metrics.c

@@ -22,12 +22,12 @@ static atomic_t connection_count = ATOMIC_INIT(0);
 #if CONFIG_MEMFAULT_NCS_STACK_METRICS
 static struct memfault_ncs_metrics_thread metrics_threads[] = {
 	{
-		.thread_name = "BT RX",
+		.thread_name = "BT RX WQ",
 		.key = MEMFAULT_METRICS_KEY(ncs_bt_rx_unused_stack)
 	},
 	{
-		.thread_name = "BT TX",
-		.key = MEMFAULT_METRICS_KEY(ncs_bt_tx_unused_stack)
+		.thread_name = "BT LW WQ",
+		.key = MEMFAULT_METRICS_KEY(ncs_bt_lw_wq_unused_stack)
 	}
 };
 #endif /* CONFIG_MEMFAULT_NCS_STACK_METRICS */