feat(sysmon): add API to start or stop sysmon and dump FPS info (#8533)

Signed-off-by: wangxuedong <wangxuedong@xiaomi.com>
Signed-off-by: wxd <xaowang96@gmail.com>

docs/src/details/auxiliary-modules/index.rst

@@ -18,5 +18,6 @@ Auxiliary Modules
     obj_property
     observer/index
     snapshot
+    sysmon
     test
     translation

docs/src/details/auxiliary-modules/sysmon.rst

@@ -0,0 +1,139 @@
+.. _sysmon:
+
+=======================
+System Monitor (sysmon)
+=======================
+
+The System Monitor module provides real-time monitoring of system performance
+metrics directly on your display. It supports both performance monitoring
+(CPU usage and FPS) and memory monitoring (used memory and fragmentation).
+
+Dependencies
+************
+- Requires ``LV_USE_LABEL = 1`` in lv_conf.h
+- Requires ``LV_USE_OBSERVER = 1`` in lv_conf.h
+- Requires ``LV_USE_SYSMON = 1`` in lv_conf.h
+
+.. _sysmon_usage:
+
+Usage
+*****
+
+Configuration
+--------------
+Enable in ``lv_conf.h``:
+
+.. code-block:: c
+
+    /* Main sysmon enable */
+    #define LV_USE_SYSMON 1
+
+    /* Performance monitor (CPU% and FPS) */
+    #define LV_USE_PERF_MONITOR 1
+
+    /* Memory monitor (used + fragmentation) */
+    #define LV_USE_MEM_MONITOR 1
+
+    /* Optional: refresh period in ms */
+    #define LV_SYSMON_REFR_PERIOD_DEF 300
+
+    /* Optional: log to console instead of screen */
+    #define LV_USE_PERF_MONITOR_LOG_MODE 0
+
+Creating Monitors
+-----------------
+.. code-block:: c
+
+    /* Create generic monitor */
+    lv_obj_t * sysmon = lv_sysmon_create(lv_display_get_default());
+
+    /* Create performance monitor */
+    lv_sysmon_show_performance(NULL);  /* NULL = default display */
+
+    /* Create memory monitor */
+    lv_sysmon_show_memory(NULL);
+
+Performance Monitor
+-------------------
+Tracks:
+- FPS (Frames Per Second)
+- CPU usage (%)
+- Render time (ms)
+- Flush time (ms)
+- Self CPU usage (%) if enabled
+
+Display format:
+.. code-block::
+
+    32 FPS, 45% CPU
+    8 ms
+
+Where:
+- Line 1: FPS, Total CPU%
+- Line 2: Total time (Render | Flush)
+
+Pause and Resume
+****************
+
+:cpp:expr:`lv_sysmon_performance_pause(disp)` pauses the perf monitor.
+
+:cpp:expr:`lv_sysmon_performance_resume(disp)` resumes the perf monitor.
+
+Memory Monitor
+--------------
+Displays:
+- Current memory usage (kB and %)
+- Peak memory usage (kB)
+- Fragmentation (%)
+
+Display format:
+.. code-block::
+
+    24.8 kB (76%)
+    32.4 kB max, 18% frag.
+
+Positioning
+-----------
+Configure positions in lv_conf.h:
+
+.. code-block:: c
+
+    /* Top-right corner */
+    #define LV_USE_PERF_MONITOR_POS LV_ALIGN_TOP_RIGHT
+
+    /* Bottom-right corner */
+    #define LV_USE_MEM_MONITOR_POS LV_ALIGN_BOTTOM_RIGHT
+
+
+Implementation Details
+**********************
+
+Initialization
+--------------
+Maintains:
+- Global memory monitor (``sysmon_mem``)
+- Per-display performance structures
+
+Performance Measurement
+-----------------------
+Event-based collection:
+
++----------------------+--------------------------------+
+| Event                | Measurement                    |
++======================+================================+
+| LV_EVENT_REFR_START  | Refresh interval start         |
++----------------------+--------------------------------+
+| LV_EVENT_REFR_READY  | Record refresh duration        |
++----------------------+--------------------------------+
+| LV_EVENT_RENDER_START| Render time start              |
++----------------------+--------------------------------+
+| LV_EVENT_RENDER_READY| Record render duration         |
++----------------------+--------------------------------+
+| LV_EVENT_FLUSH_*     | Measure flush operations       |
++----------------------+--------------------------------+
+
+Timers
+------
+- Performance: ``perf_update_timer_cb``
+- Memory: ``mem_update_timer_cb``
+- Default period: 300ms (``LV_SYSMON_REFR_PERIOD_DEF``)