create_loop.c

   1 #include <stdio.h>
   2 #include <sys/time.h>
   3 #include <time.h>
   4 #include <errno.h>
   5 #include <string.h>
   6 #include <unistd.h>
   7 #include <fcntl.h>
   8
   9 static struct timeval tp1,tp2;
  10
  11 static void start_timer()
  12 {
  13         gettimeofday(&tp1,NULL);
  14 }
  15
  16 static double end_timer()
  17 {
  18         gettimeofday(&tp2,NULL);
  19         return (tp2.tv_sec + (tp2.tv_usec*1.0e-6)) -
  20                 (tp1.tv_sec + (tp1.tv_usec*1.0e-6));
  21 }
  22
  23
  24 static void create_loop(const char *fname)
  25 {
  26         unsigned count = 0;
  27         int fd;
  28         start_timer();
  29
  30         while (1) {
  31                 count++;
  32
  33                 unlink(fname);
  34                 fd = open(fname, O_RDWR|O_CREAT|O_TRUNC|O_EXCL, 0644);
  35                 if (fd == -1) {
  36                         perror(fname);
  37                         exit(1);
  38                 }
  39                 close(fd);
  40
  41                 if (end_timer() > 1.0) {
  42                         printf("%.0f ops/sec\r", count/end_timer());
  43                         fflush(stdout);
  44                         start_timer();
  45                         count=0;
  46                 }
  47         }
  48 }
  49
  50 static void usage(void)
  51 {
  52         printf("usage: create_loop <file>\n");
  53 }
  54
  55 int main(int argc, char *argv[])
  56 {
  57         if (argc < 2) {
  58                 usage();
  59                 exit(1);
  60         }
  61         create_loop(argv[1]);
  62         return 0;
  63 }