Add task stats

Author: mikee47

samples/Esp32_Dual_Core/README.rst

@@ -1,8 +1,51 @@
 ESP32 Dual Core
 ===============
 
+.. highlight:: text
+
 Basic example of using second core of Esp32 chip.
 
-Code should be in IRAM and avoid accessing flash, especially the filing system.
+.. important::
+
+    Sming is NOT thread-safe! In general, only re-entrant code and code intended to be called from interrupt context is safe to use from multiple cores.
+
+If code is timing sensitive then it should be run from IRAM.
+
+Flash and filing system access must only be done from the main Sming application.
+
+
+Required steps
+--------------
+
+- Override IDF SDK config settings as in ``esp-dual-core.cfg``.
+- Add line to project's ``component.mk``: *SDK_CUSTOM_CONFIG := esp32-dual-core.cfg*
+- Add application code to run on second core and call to start for that core
+- Run `make sdk-config-clean` to ensure custom configuration values are picked up
+
+The custom configuration enables dual-core operation (``CONFIG_FREERTOS_UNICORE=n``) and disables the idle task for the second core (``CONFIG_ESP_TASK_WDT_CHECK_IDLE_TASK_CPU1=n``). This ensures that code will run uninterrupted.
+
+Task stats shows this when running::
+
+    # | Core | Prio | Handle   | Run Time | % Time | Name
+    1 |   0  |   24 | 3ffaee9c |        0 |    0%  | ipc0
+    3 |   0  |   22 | 3ffaf568 |     3226 |    0%  | esp_timer
+    5 |   0  |    0 | 3ffb8974 |  1996774 |   49%  | IDLE0
+    2 |   1  |   24 | 3ffaf404 |        0 |    0%  | ipc1
+    8 |   1  |   18 | 3ffbdf44 |    33156 |    0%  | Sming
+    7 |   1  |    5 | 3ffb9d24 |  1966844 |   49%  | Sming2
+    6 |   1  |    0 | 3ffb9118 |        0 |    0%  | IDLE1
+
+
+Bare Metal
+----------
+
+Because we rely on the IDF and its dependency on FreeRTOS, the above approach also ensures that calls such as ``System.queueCallback`` will work. This is the recommended way to communicate between code running on different cores.
+
+The default mode for Sming runs without FreeRTOS on the second core (*CONFIG_FREERTOS_UNICORE=y*) which provides a smaller set of tasks and thus lower system memory usage::
+
+    # | Core | Prio | Handle   | Run Time | % Time | Name
+    1 |   0  |   22 | 3ffaf470 |       29 |    0%  | esp_timer
+    4 |   0  |   18 | 3ffb778c |    11016 |    0%  | Sming
+    3 |   0  |    0 | 3ffafdb0 |  1988955 |   49%  | IDLE
 
-Sming is NOT thread-safe!
+In this state it is technically possible to get code running on the second core by hooking a low-level startup routine. The application would need to handle stack/heap allocation and code would be far more limited in what it can safely do.

samples/Esp32_Dual_Core/app/application.cpp

@@ -1,29 +1,55 @@
 #include <SmingCore.h>
+#include <Services/Profiling/TaskStat.h>
+
+namespace
+{
+Profiling::TaskStat taskStat(Serial);
+SimpleTimer statTimer;
 
 void handleNotification(uint32_t param)
 {
-	Serial << "NOTIFY " << param << endl;
+	debug_i("NOTIFY %u", param);
 }
 
 // Code to run on second CPU
 void IRAM_ATTR app2_main(void*)
 {
 	static unsigned count;
 
+	// Using a polled timer has virtually zero overhead as it accesses timing hardware directly
+	PeriodicFastUs timer(100);
+
 	for(;;) {
-		System.queueCallback(handleNotification, count);
+		if(!timer.expired()) {
+			continue;
+		}
+
+		if(count % 10000 == 0) {
+			System.queueCallback(handleNotification, count);
+
+			debug_i("TICK");
+
+			// This is required if CONFIG_ESP_TASK_WDT_CHECK_IDLE_TASK_CPU1=y
+			// WDT.alive();
+		}
 		++count;
-		delay(500);
 	}
 }
 
+} // namespace
+
 void init()
 {
 	Serial.begin(SERIAL_BAUD_RATE);
 	Serial.systemDebugOutput(true);
 
 	Serial.println(_F("ESP32 dual-core demo."));
 
+	// Provide some periodic status so we can see what tasks are active
+	statTimer.initializeMs<2000>([]() { taskStat.update(); });
+	statTimer.start();
+
+	// Create task running on second core
 	const unsigned stackSize = 2048;
 	const unsigned priority = 5;
 	xTaskCreatePinnedToCore(app2_main, "Sming2", stackSize, nullptr, priority, nullptr, 1);

samples/Esp32_Dual_Core/esp32-dual-core.cfg

@@ -1 +1,6 @@
+# Enable dual-core operation
 CONFIG_FREERTOS_UNICORE=n
+
+# If watchdog is required, code will need to suspend periodically via `WDT.alive`.
+# Leaving it disabled ensures code runs uninterrupted on second core.
+CONFIG_ESP_TASK_WDT_CHECK_IDLE_TASK_CPU1=n