test/sysperf/mutex2.c

   1 /*
   2  * mutex2.c
   3  *
   4  * $DragonFly: src/test/sysperf/mutex2.c,v 1.2 2006/04/22 22:32:52 dillon Exp $
   5  */
   6
   7 #include "blib.h"
   8
   9 int *mtx;
  10
  11 int
  12 main(int ac, char **av)
  13 {
  14     long long count = 0;
  15     long long max;
  16     int j;
  17     int *counter;
  18     pid_t pid;
  19
  20     printf("Test simple locked bus cycle mutex latency\n");
  21     printf("auto-forks two processes for the test with shared memory\n");
  22     printf("This test is only useful on a SMP box\n");
  23
  24     start_timing();
  25     mtx = mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_SHARED|MAP_ANON, -1, 0);
  26     counter = mtx + 64;
  27     while (stop_timing(0, NULL) == 0) {
  28         for (j = 0; j < 100; ++j) {
  29             get_mtx(1);
  30             rel_mtx();
  31         }
  32         count += 100;
  33     }
  34     max = count;
  35     *mtx = 0;
  36
  37     start_timing();
  38     for (count = 0; count < max; count += 100) {
  39         for (j = 0; j < 100; ++j) {
  40             get_mtx(1);
  41             rel_mtx();  /* release */
  42             ++counter[64];
  43         }
  44     }
  45     stop_timing(count, "complex_mtx(uncontested/1cpu)");
  46
  47     if ((pid = fork()) == 0) {
  48         for (;;) {
  49             for (j = 0; j < 100; ++j) {
  50                 get_mtx(2);
  51                 rel_mtx();      /* release */
  52                 ++counter[128];
  53             }
  54         }
  55     } else {
  56         start_timing();
  57         for (count = 0; count < max; count += 100) {
  58             for (j = 0; j < 100; ++j) {
  59                 get_mtx(1);
  60                 rel_mtx();      /* release */
  61                 ++counter[64];
  62             }
  63         }
  64         stop_timing(count, "complex_mtx");
  65         printf("proc1=%d proc2=%d\n", counter[64], counter[128]);
  66         kill(pid, 9);
  67     }
  68     return(0);
  69 }
  70