perf/heap.c

   1 #include <stdio.h>
   2 #include <stdlib.h>
   3
   4 #define NLIVE 1000000
   5
   6 #define NITERS (3*1000*1000)
   7
   8 char* arr[NLIVE];
   9
  10 int main ( int argc, char* argv[] )
  11 {
  12    int i, j, nbytes = 0;
  13    int pdb = 0;
  14    int jpdb;
  15
  16    if (argc > 1) {
  17       pdb = atoi(argv[1]);
  18    }
  19
  20    printf("initialising\n");
  21    for (i = 0; i < NLIVE; i++)
  22       arr[i] = NULL;
  23
  24    printf("running\n");
  25    j = -1;
  26    for (i = 0; i < NITERS; i++) {
  27       j++;
  28       if (j == NLIVE) j = 0;
  29       if (arr[j])
  30          free(arr[j]);
  31       arr[j] = malloc(nbytes);
  32       if (pdb > 0) {
  33          // create some partially defined bytes in arr[j]
  34          for (jpdb=0; jpdb<nbytes; jpdb = jpdb+pdb) {
  35             arr[j][jpdb] &= (jpdb & 0xff);
  36          }
  37       }
  38
  39       // Cycle through the sizes 0,8,16,24,32.  Zero will get rounded up to
  40       // 8, so the 8B bucket will get twice as much traffic.
  41       nbytes += 8;
  42       if (nbytes > 32)
  43          nbytes = 0;
  44    }
  45
  46    for (i = 0; i < NLIVE; i++)
  47       if (arr[i])
  48          free(arr[i]);
  49
  50    printf("done\n");
  51    return 0;
  52 }