src/tests/system/benchmarks/syscallbench.c

   1 /*
   2  * from ftp://ftp.netbsd.org/pub/NetBSD/misc/gmcgarry/bench/syscallbench.tar.gz
   3  *
   4  * gcc -Wall -Werror -O3 -static -o ctx ctx.c
   5  */
   6
   7 #include <stdio.h>
   8 #include <stdlib.h>
   9 #include <sys/time.h>
  10 #include <unistd.h>
  11
  12 #include <OS.h>
  13
  14 #define ITERATIONS      500000
  15
  16 static void
  17 usage(void)
  18 {
  19         printf("syscallbench [-h]\n");
  20         exit(1);
  21 }
  22
  23 static int null_func(void)
  24 {
  25         return 0;
  26 }
  27
  28 static unsigned long test_func(int (*func)(void))
  29 {
  30         struct timeval before, after;
  31         unsigned long elapsed;
  32         int i;
  33
  34         gettimeofday(&before, NULL);
  35         for (i=0; i<ITERATIONS; i++) {
  36                 func();
  37         }
  38         gettimeofday(&after, NULL);
  39
  40         elapsed = 1000000 * (after.tv_sec - before.tv_sec);
  41         elapsed += after.tv_usec - before.tv_usec;
  42         return elapsed;
  43 }
  44
  45 int
  46 main(int argc, char *argv[])
  47 {
  48         unsigned long overhead;
  49         unsigned long libcall;
  50         unsigned long syscall;
  51
  52         if (argc > 1)
  53                 usage();
  54
  55         overhead = test_func(&null_func);
  56         libcall = test_func((void *)&getpid); // getpid is currently implemented as a library function returning the value of a global
  57         syscall = test_func((void *)&is_computer_on);
  58
  59         printf("overhead time: %ld nanoseconds\n",
  60             (1000*(overhead))/ITERATIONS);
  61
  62         printf("libcall time: %ld nanoseconds\n",
  63             (1000*(libcall-overhead))/ITERATIONS);
  64
  65         printf("syscall time: %ld nanoseconds\n",
  66             (1000*(syscall-overhead))/ITERATIONS);
  67
  68         return (0);
  69 }