test/sysperf/cmp.c

   1 /*
   2  * cmp.c
   3  *
   4  * Test for comparing pointers vs bit-testing.
   5  *
   6  * $DragonFly: src/test/sysperf/cmp.c,v 1.1 2005/08/03 13:37:27 hmp Exp $
   7  */
   8
   9 #include "blib.h"
  10
  11 #define LOOP 1000000000
  12
  13 static void nop(void) { }
  14
  15 struct f {
  16         void (*nop_ptr)(void);
  17         int mask;
  18 } foo;
  19 #define SOME_MASK       0x00800
  20
  21 struct f *fp = &foo;
  22
  23 int
  24 main(int ac, char **av)
  25 {
  26     int i;
  27         struct f *fp = &foo;
  28         foo.nop_ptr = nop;
  29         foo.mask = SOME_MASK;
  30
  31     printf("compare nop() function pointer against NULL (struct not pointer)\n");
  32     start_timing();
  33     for (i = 0; i < LOOP; ++i)
  34                 if (foo.nop_ptr == NULL)
  35                         ;
  36     stop_timing(LOOP, "loop1/cmp-pointer");
  37
  38         printf("compare nop() function pointer against NULL (struct pointer)\n");
  39     start_timing();
  40     for (i = 0; i < LOOP; ++i)
  41                 if (fp->nop_ptr == NULL)
  42                         ;
  43     stop_timing(LOOP, "loop2/cmp-pointer");
  44
  45         printf("compare bitmask checking\n");
  46     start_timing();
  47     for (i = 0; i < LOOP; ++i)
  48                 if (foo.mask & SOME_MASK)
  49                         ;
  50     stop_timing(LOOP, "loop3/cmp-bitmask");
  51
  52
  53     return(0);
  54 }
  55