MicrosTimingTest.ino

#include <functional>
void setup() {
  Serial.begin(115200);
  delay(1000);
  Serial.println("");
  Serial.println("start");
}

uint32_t measure_time(std::function<void(void)> fn) 
{
  uint32_t t_start = micros();
  fn();
  uint32_t t_end = micros();
  return t_end - t_start;
}


static uint32_t s_loop_end_timestamp = 0;
static uint32_t s_loop_counter = 0;
void loop() {
  uint32_t loop_start_timestamp = micros();

  uint32_t empty_loop_duration = measure_time( [](){
    for (volatile int i = 0; i < 1000000; ++i) {}
  });

  uint32_t micros_loop_duration = measure_time( [](){
    for (volatile int i = 0; i < 1000000; ++i) {
      volatile int t = micros();
    }
  });

  Serial.printf("Loop %4d t(empty loop)=%d t(micros loop)=%d t(loop end -> loop start)=%d\r\n",
                s_loop_counter, empty_loop_duration, micros_loop_duration, loop_start_timestamp - s_loop_end_timestamp);


  delay(100);
  
  ++s_loop_counter;
  s_loop_end_timestamp = micros();
}