GNU gprof

GNU gprof
GNU gprof
Using the profiler gprof

// -- $ mkdir src; vim src/hello.c --
#include <stdio.h>

static void function2(int i) {
  printf("%d\n", i);
}

static int function1(int x) {
  int i;
  for (i = 0; i < x; i++) {
    function2(x);
  }
  return x + 1;
}

int main(void) {
  int i, total;

  total = 0;

  for (i = 0; i < 5000; i++) {
    total = function1(i);
    function2(total);
  }
  return 0;
}


// -- $ vim makefile --
all: hello.prof
	cat hello.time
	cat hello.prof

hello.prof: gmon.out
	gprof -b hello gmon.out > hello.prof

gmon.out: hello
	/usr/bin/time -f "real %e\nuser %U\nsys %S\nCPU %P\n" -o hello.time ./hello > /dev/null

hello: src/hello.c
	gcc -Wall -pg -o hello ./src/hello.c

clean:
	rm -f hello*
	rm -f gmon.out

// -- make --
$ make all
gcc -Wall -pg -o hello ./src/hello.c
/usr/bin/time -f "real %e\nuser %U\nsys %S\nCPU %P\n" -o hello.time ./hello > /dev/null
gprof -b hello gmon.out > hello.prof
cat hello.time
real 1.49
user 1.47
sys 0.00
CPU 99%

cat hello.prof
Flat profile:

Each sample counts as 0.01 seconds.
  %   cumulative   self              self     total
 time   seconds   seconds    calls  us/call  us/call  name
 73.53      0.08     0.08     5000    16.18    16.18  function1
 27.57      0.11     0.03                             frame_dummy
  0.00      0.11     0.00 12502500     0.00     0.00  function2

                        Call graph


granularity: each sample hit covers 2 byte(s) for 8.99% of 0.11 seconds

index % time    self  children    called     name
                0.08    0.00    5000/5000        main [2]
[1]     72.7    0.08    0.00    5000         function1 [1]
                0.00    0.00 12497500/12502500     function2 [4]
...