A simple profiler written in C

example.c

// compile with: gcc -std=gnu99 example.c profiler.c -lrt
#include "profiler.h"
#include <stdio.h>

FILE *devnull;
Profiler p_total;
Profiler p_foo8;
Profiler p_foo10;

// Run n! times
void foo(int n) {
	int i;
	if (n == 0)
		return;

	for (i = 0; i < n; i++)
		foo(n-1);

	// Do some fancy calculations
	int x = n*n*n % 3;
	fprintf(devnull, "%d\n", x);
}

int main() {
	profiler_init(&p_total, "total");
	profiler_start(&p_total);

	devnull = fopen("/dev/null", "w");
	profiler_init(&p_foo8, "foo(8)");
	profiler_init(&p_foo10, "foo(10)");

	profiler_start(&p_foo8);
	foo(8);
	profiler_stop(&p_foo8);

	profiler_start(&p_foo10);
	foo(10);
	profiler_stop(&p_foo10);			

	fclose(devnull);

	profiler_stop(&p_total);

	profiler_print(&p_total);
	profiler_print(&p_foo8);
	profiler_print(&p_foo10);

	profiler_free(&p_foo8);
	profiler_free(&p_foo10);
	profiler_free(&p_total);		
	return 0;
}

profiler.c

#include "profiler.h"

#include <string.h>
#include <stdlib.h>
#include <stdio.h>

void profiler_init(Profiler *prof, const char *name)
{
	prof->name = strndup(name, 30);
	prof->runs = 0;
	prof->total = 0.0;
}

void profiler_free(Profiler *prof)
{
	free(prof->name);
}

void profiler_print(Profiler *prof)
{
	printf("%-15s % 12lld %ld\n",
	       prof->name, prof->total, prof->runs);
}

profiler.h

#ifndef __PROFILER_H__
#define __PROFILER_H__

#include <time.h>

typedef unsigned long long uint64;
typedef struct _Profiler Profiler;

struct _Profiler {
	char *name;
	long runs;
	uint64 total;
	uint64 t0;
};

void profiler_init(Profiler *prof, const char *name);

void profiler_free(Profiler *prof);

void profiler_print(Profiler *prof);

static __inline__ uint64 getticks(void)
{
	struct timespec tp;
	clock_gettime(CLOCK_MONOTONIC, &tp);
	return tp.tv_sec*1000000000 + tp.tv_nsec;
}

static __inline__ void profiler_start(Profiler *prof)
{
	prof->t0 = getticks();
	prof->runs++;
}

static __inline__ void profiler_stop(Profiler *prof)
{
	prof->total += getticks() - prof->t0;
}

#endif /* end of include guard: __PROFILER_H__ */