mdw@git.distorted.org.uk Git - runlisp/blob - bench/timeit.c

   1 #include <errno.h>
   2 #include <stdarg.h>
   3 #include <stdio.h>
   4 #include <stdlib.h>
   5 #include <string.h>
   6 #include <time.h>
   7
   8 #include <unistd.h>
   9 #include <sys/resource.h>
  10 #include <sys/time.h>
  11 #include <sys/wait.h>
  12
  13 static const char *progname = "timeit";
  14
  15 static void set_progname(const char *prog)
  16 {
  17   const char *p;
  18
  19   p = strrchr(prog, '/');
  20   progname = p ? p + 1 : progname;
  21 }
  22
  23 static void lose(const char *msg, ...)
  24 {
  25   va_list ap;
  26
  27   va_start(ap, msg);
  28   fprintf(stderr, "%s: ", progname);
  29   vfprintf(stderr, msg, ap);
  30   fputc('\n', stderr);
  31   va_end(ap);
  32   exit(127);
  33 }
  34
  35 static double timeval_to_float(const struct timeval *tv)
  36   { return (tv->tv_sec + tv->tv_usec*1e-6); }
  37
  38 int main(int argc, char *argv[])
  39 {
  40   struct rusage ru;
  41   struct timeval t0, t1, t;
  42   pid_t kid;
  43   int i, st;
  44
  45   set_progname(argv[0]);
  46   gettimeofday(&t0, 0);
  47   kid = fork(); if (kid < 0) lose("fork failed: %s", strerror(errno));
  48   if (!kid) {
  49     execvp(argv[1], argv + 1);
  50     lose("exec (`%s') failed: %s", argv[1], strerror(errno));
  51   }
  52   if (wait4(kid, &st, 0, &ru) < 0) lose("wait failed: %s", strerror(errno));
  53   gettimeofday(&t1, 0);
  54   if (st) {
  55     if (WIFSIGNALED(st))
  56       lose("program killed by signal %d\n", WTERMSIG(st));
  57     else if (WIFEXITED(st))
  58       lose("program failed with status %d\n", WEXITSTATUS(st));
  59     else
  60       lose("program exited with incomprehensible status 0x%04x\n", st);
  61   }
  62
  63   if (t0.tv_usec > t1.tv_usec) {
  64     t.tv_sec = t1.tv_sec - t0.tv_sec - 1;
  65     t.tv_usec = t1.tv_usec + 1000000 - t0.tv_usec;
  66   } else {
  67     t.tv_sec = t1.tv_sec - t0.tv_sec;
  68     t.tv_usec = t1.tv_usec - t0.tv_usec;
  69   }
  70
  71   for (i = 1; i < argc; i++) {
  72     if (i > 1) fputc(' ', stderr);
  73     fputs(argv[i], stderr);
  74   }
  75   fprintf(stderr, ": elapsed = %.4fs; user = %.4fs; system = %.4fs\n",
  76           timeval_to_float(&t),
  77           timeval_to_float(&ru.ru_utime),
  78           timeval_to_float(&ru.ru_stime));
  79   return (0);
  80 }