.. _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 :c:macro:LV_USE_LABEL = 1 in lv_conf.h
Requires :c:macro:LV_USE_OBSERVER = 1 in lv_conf.h
Requires :c:macro: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:: text

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:: text

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:

.. container:: tighter-table-3

+----------------------+--------------------------------+
| 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 (:c:macro:LV_SYSMON_REFR_PERIOD_DEF)