Simple code profiler for ARMv7-M Cortex-M3 and higher CPU families.

---

Features

• Compatible with RTOS.
• Accuracy is around 1us.
• Easy switch between Release/Debug mode.

---

Usage

• Initalize profiler:

  CORTEX_PROFILE_BEGIN(
    72000000, /* System core clock value            */
    printf    /* Any printf implementation callback */
  );

• Start profiling session:

CORTEX_PROFILE_BEGIN("session name");

• Insert event command after each tracked case:

DoAwesomeWork();
CORTEX_PROFILE_EVENT("DoAwesomeWork() event");

The maximum number of events may be configured in cortex_profile.h file by assign a new value to CORTEX_PROFILE_MAX_EVENTS

• End profiling session:

CORTEX_PROFILE_END();

⚠️ Don't forget to end the seesion to restore global IRQ settings.

• Build your program in debug mode with USE_CORTEX_PROFILE define:

make -D USE_CORTEX_PROFILE my_program.c -o my_program

• Run.

---

Example

  CORTEX_PROFILE_INIT(
    72000000,
    printf
  );

  ...

  CORTEX_PROFILE_BEGIN("Startup your job");

  InitializeFlawlessTask();
  CORTEX_PROFILE_EVENT("Initialized flawless task");

  HAL_GPIO_WritePin(LED_YELLOW_GPIO_Port, LED_YELLOW_Pin, GPIO_PIN_SET);
  CORTEX_PROFILE_EVENT("Turn on LED");

  DoAwesomeWork(1000);
  CORTEX_PROFILE_EVENT("DoAwesomeWork 1000 ticks");
  
  HAL_GPIO_WritePin(LED_YELLOW_GPIO_Port, LED_YELLOW_Pin, GPIO_PIN_RESET);
  CORTEX_PROFILE_EVENT("Turn off LED");

  DoAwesomeWork(5000);
  CORTEX_PROFILE_EVENT("DoAwesomeWork 5000 ticks");

  CORTEX_PROFILE_END();

Output

Profiling "Startup your job" sequence: 
|---------- Event ----------|--- Timestamp ---|----- Delta -----|
| Initialized flawless task |            8 us |            8 us |
| Turn on LED               |           10 us |            2 us |
| DoAwesomeWork 1000 ticks  |          135 us |          125 us |
| Turn off LED              |          137 us |            2 us |
| DoAwesomeWork 5000 ticks  |          763 us |          626 us |

---

Notes

To redirect data to SWV/UART I prefer to use tiny printf implementation for embedded systems. Feel free to choose whatever you want ;)

Redirection

redirect.c

/* Example standard GNU C library printf redirection */

#include <errno.h>
#include <sys/unistd.h>

int _write(int file, char* data, int len)
{
  if ((file != STDOUT_FILENO) && (file != STDERR_FILENO)) {
    errno = EBADF;
    return -1;
  }

  for (int idx = 0; idx < len; ++idx) {
    ITM_SendChar(data[idx]);
  }

  return len;
}