test/sysperf/mutex1.c

   1 /*
   2  * mutex1.c
   3  *
   4  * $DragonFly: src/test/sysperf/mutex1.c,v 1.2 2006/04/22 22:34:06 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             try_spin_mtx();
  30             rel_spin_mtx();
  31         }
  32         count += 100;
  33     }
  34     max = count;
  35     *mtx = 0;
  36
  37     /*
  38      * Single cpu case
  39      */
  40     start_timing();
  41     for (count = 0; count < max; count += 100) {
  42         for (j = 0; j < 100; ++j) {
  43             while (try_spin_mtx() != 0)
  44                 ;
  45             rel_spin_mtx();     /* release */
  46             ++counter[64];
  47         }
  48     }
  49     stop_timing(count, "simple_mtx(uncontested/1cpu)");
  50
  51     if ((pid = fork()) == 0) {
  52         for (;;) {
  53             for (j = 0; j < 100; ++j) {
  54                 while (try_spin_mtx() != 0)
  55                     ;
  56                 rel_spin_mtx(); /* release */
  57                 ++counter[128];
  58             }
  59         }
  60     } else {
  61         start_timing();
  62         for (count = 0; count < max; count += 100) {
  63             for (j = 0; j < 100; ++j) {
  64                 while (try_spin_mtx() != 0)
  65                     ;
  66                 rel_spin_mtx(); /* release */
  67                 ++counter[64];
  68             }
  69         }
  70         stop_timing(count, "simple_mtx");
  71         printf("proc1=%d proc2=%d\n", counter[64], counter[128]);
  72         kill(pid, 9);
  73     }
  74     return(0);
  75 }
  76