feat(freertos): allow overriding idle percentage calculation (#9647)

Kconfig

@@ -162,6 +162,15 @@ menu "LVGL configuration"
 			Unblocking an RTOS task with a direct notification is 45% faster and uses less RAM
 			than unblocking a task using an intermediary object such as a binary semaphore.
 			RTOS task notifications can only be used when there is only one task that can be the recipient of the event.
+		config LV_OS_IDLE_PERCENT_CUSTOM
+			bool "Custom idle percentage calculation"
+			default n
+			depends on LV_OS_FREERTOS
+			help
+				Enable this to provide a custom implementation of lv_os_get_idle_percent.
+				This is useful for multi-core systems where the default
+				FreeRTOS implementation might not sufficiently track idle time across all cores.
+
 	endmenu
 
 	menu "Rendering Configuration"

docs/src/integration/rtos/freertos.rst

@@ -31,3 +31,67 @@ the idle function. To enable this, the following needs to be added in
 
     #define traceTASK_SWITCHED_IN()   lv_freertos_task_switch_in(pxCurrentTCB->pcTaskName);
     #define traceTASK_SWITCHED_OUT()  lv_freertos_task_switch_out();
+
+Alternatively, on multi-core environments (like the ESP32 SMP), this default
+implementation can be insufficient or inaccurate. In this case, you can set
+``LV_OS_IDLE_PERCENT_CUSTOM`` to ``1`` in ``lv_conf.h`` to disable the default
+implementation. Then, you can provide a custom implementation of
+:cpp:expr:`lv_os_get_idle_percent` tailored to your environment
+(e.g., using ``uxTaskGetSystemState()``) without modifying LVGL source files.
+
+Example: Custom implementation for ESP32 SMP
+********************************************
+
+For multi-core environments like the ESP32 (which uses dual-core SMP), the default 
+implementation might not track all idle tasks. Below is an example of a custom 
+implementation using ``uxTaskGetSystemState()``. This requires 
+``configGENERATE_RUN_TIME_STATS`` and ``configUSE_TRACE_FACILITY`` to be enabled 
+in your ``FreeRTOSConfig.h`` (or via menuconfig for ESP-IDF).
+
+.. code-block:: c
+
+    #include "FreeRTOS.h"
+    #include "task.h"
+    #include <string.h>
+
+    uint32_t lv_os_get_idle_percent(void) {
+        static uint32_t last_idle_time = 0;
+        static uint32_t last_total_time = 0;
+        
+        uint32_t ulTotalRunTime;
+        uint32_t ulIdleTime = 0;
+        
+        TaskStatus_t *pxTaskStatusArray;
+        UBaseType_t uxArraySize, x;
+        
+        uxArraySize = uxTaskGetNumberOfTasks();
+        pxTaskStatusArray = pvPortMalloc(uxArraySize * sizeof(TaskStatus_t));
+        
+        if (pxTaskStatusArray == NULL) {
+            return 0;
+        }
+        
+        uxArraySize = uxTaskGetSystemState(pxTaskStatusArray, uxArraySize, &ulTotalRunTime);
+        for (x = 0; x < uxArraySize; x++) {
+            /* ESP32 has IDLE0 and IDLE1 tasks */
+            if (strcmp(pxTaskStatusArray[x].pcTaskName, "IDLE0") == 0 ||
+                strcmp(pxTaskStatusArray[x].pcTaskName, "IDLE1") == 0) {
+                ulIdleTime += pxTaskStatusArray[x].ulRunTimeCounter;
+            }
+        }
+        vPortFree(pxTaskStatusArray);
+        
+        uint32_t idle_diff = ulIdleTime - last_idle_time;
+        uint32_t total_diff = ulTotalRunTime - last_total_time;
+        
+        last_idle_time = ulIdleTime;
+        last_total_time = ulTotalRunTime;
+        
+        if (total_diff == 0) return 0;
+        
+        /* Combined idle percentage across both cores (0-200 on dual-core) */
+        uint32_t idle_pct = (idle_diff * 100) / total_diff;
+
+        /* For Sysmon, we usually want average load across all cores (0-100) */
+        return idle_pct / 2; /* Adjust divisor based on your CPU core count */
+    }

env_support/cmsis-pack/lv_conf_cmsis.h

@@ -127,6 +127,9 @@
      * RTOS task notifications can only be used when there is only one task that can be the recipient of the event.
      */
     #define LV_USE_FREERTOS_TASK_NOTIFY 1
+
+    /* Enable this to provide a custom implementation of lv_os_get_idle_percent. */
+    #define LV_OS_IDLE_PERCENT_CUSTOM 0
 #endif
 
 /*========================

lv_conf_template.h

@@ -119,6 +119,9 @@
      * RTOS task notifications can only be used when there is only one task that can be the recipient of the event.
      */
     #define LV_USE_FREERTOS_TASK_NOTIFY 1
+
+    /* Enable this to provide a custom implementation of lv_os_get_idle_percent. */
+    #define LV_OS_IDLE_PERCENT_CUSTOM 0
 #endif
 
 /*========================

src/lv_conf_internal.h

@@ -312,6 +312,15 @@
             #define LV_USE_FREERTOS_TASK_NOTIFY 1
         #endif
     #endif
+
+    /* Enable this to provide a custom implementation of lv_os_get_idle_percent. */
+    #ifndef LV_OS_IDLE_PERCENT_CUSTOM
+        #ifdef CONFIG_LV_OS_IDLE_PERCENT_CUSTOM
+            #define LV_OS_IDLE_PERCENT_CUSTOM CONFIG_LV_OS_IDLE_PERCENT_CUSTOM
+        #else
+            #define LV_OS_IDLE_PERCENT_CUSTOM 0
+        #endif
+    #endif
 #endif
 
 /*========================

src/osal/lv_freertos.c

@@ -403,6 +403,7 @@ void lv_freertos_task_switch_out(void)
     else globals->freertos_non_idle_time_sum += elaps;
 }
 
+#if LV_OS_IDLE_PERCENT_CUSTOM == 0
 uint32_t lv_os_get_idle_percent(void)
 {
     if(globals->freertos_non_idle_time_sum + globals->freertos_idle_time_sum == 0) {
@@ -418,6 +419,7 @@ uint32_t lv_os_get_idle_percent(void)
 
     return pct;
 }
+#endif
 
 void lv_sleep_ms(uint32_t ms)
 {

tests/src/lv_test_perf_conf.h

@@ -121,8 +121,10 @@
             * RTOS task notifications can only be used when there is only one task that can be the recipient of the event.
             */
             #define LV_USE_FREERTOS_TASK_NOTIFY 1
-        #endif
 
+            /* Enable this to provide a custom implementation of lv_os_get_idle_percent. */
+            #define LV_OS_IDLE_PERCENT_CUSTOM 0
+        #endif
         /*========================
         * RENDERING CONFIGURATION
         *========================*/