Snippet for timing analysis.

01_timing.cpp

#define SLOTS 100

unsigned long _last[SLOTS];
size_t _index = 0;


void set(void) {
  _last[_index] = millis();
  _index++;
}

void delta(char* label) {
  _index--;
  char buf[80];
  sprintf(buf, "%04i %s", millis() - _last[_index], label);
  Serial.println(buf);
}

02_usage.cpp

extern void set(void);
extern void delta(char*);


void some_function(void) {
  set();                     // Record current time in slot 0.

  set();                     // Record current time in slot 1.
  some_call();
  delta("some_call");        // Write the duration of `some_call()` to serial, free slot 1.

  set();                     // Record current time in slot 1.
  some_other_call();
  delta("some_other_call");  // Write the duration of `some_other_call()` to serial, free slot 1.

  delta("total");            // Write the duration of the entire function to serial, free slot 0.
}

03_output.txt

0247 some_call
0527 some_other_call
0774 total