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

Usage¶

Configuration¶

Enable in lv_conf.h:

/* 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¶

/* 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¶

lv_sysmon_performance_pause(disp) pauses the perf monitor.

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:

/* 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)