Get CPU load as LV_USE_PERF_MONITOR

I like the informative CPU utilization value from LV_USE_PERF_MONITOR. How can I get this value in my code to output it to the terminal or send it to the server as part of telemetry?

I tried to do something like

#include "lv_sysmon.h"
uint8_t get_cpu_load() {
  lv_sysmon_ext_t *ext = (lv_sysmon_ext_t *)lv_obj_get_ext_attr(sysmon);
  return ext->cpu_avg;
}

but I couldn’t find where I should add lv_sysmon.h from