gprof reports wrong execution times

[Anton Shepelev <anton dot txt at gmail dot com>]

Hello, all

I  am  learning gprof and cannot seem to make it re-
port correct execution times.  I  am  profiling  the
follwing simple code:

   #include "test.h"
   #include <stdlib.h>
   #include <stdio.h>
   #include <time.h>

   void genwait( unsigned t )
   {    clock_t before, after;
        unsigned i;
        char line[3];
        double time_sec;
        before = clock();
        for( i = 0; i < t; i++ )
        {    sprintf(line, "a");  }
        after = clock();
        time_sec = ((double)(after - before)) / CLOCKS_PER_SEC;
        printf( "%i cycles took %2.3g seconds.0, t, time_sec );
   }

   void wait1()
   {    genwait(100000000);  }

   void wait2()
   {    genwait(800000000);  }

   void wait3()
   {    genwait(1600000000);  }

   void WorkHard()
   {    int i=0;
        wait1();
        wait2();
        wait3();
   }

and  grpof  reports  that  the wait<n> functions all
take the same time:

   index % time    self  children    called     name
   -----------------------------------------------
                   0.00    2.74       1/1           WorkHard [2]
   [4]     33.3    0.00    2.74       1         wait1 [4]
                   2.74    0.00       1/3           genwait [1]
   -----------------------------------------------
                   0.00    2.74       1/1           WorkHard [2]
   [5]     33.3    0.00    2.74       1         wait2 [5]
                   2.74    0.00       1/3           genwait [1]
   -----------------------------------------------
                   0.00    2.74       1/1           WorkHard [2]
   [6]     33.3    0.00    2.74       1         wait3 [6]
                   2.74    0.00       1/3           genwait [1]
   -----------------------------------------------

while they clearly take different times to complete,
for my program writes:

   100000000 cycles took 0.344 seconds.
   800000000 cycles took 2.86 seconds.
   1600000000 cycles took 5.7 seconds.

I  am  compiling  this  code with optimizations off:
-O0.  My full setup including the Makefile  is  here
on Google Drive:

         http://preview.tinyurl.com/hya9ody

Beware my dangerous 'clean' target which will delete
all executables in the current directory and below.

If it be a blunder of mine, please tell  me  so  and
accept my apologies.