test/sysperf/read1.c

   1 /*
   2  * read1.c
   3  *
   4  * Tests reading 1 byte at a time from a file.
   5  *
   6  * $DragonFly: src/test/sysperf/read1.c,v 1.1 2004/08/13 02:28:42 dillon Exp $
   7  */
   8
   9 #include "blib.h"
  10 #include <errno.h>
  11 #include <sys/resource.h>
  12 #include <sys/fcntl.h>
  13
  14 char Buf[8192];
  15
  16 int
  17 main(int ac, char **av)
  18 {
  19     int bytes;
  20     int fd;
  21     int i;
  22     int j;
  23     char c;
  24     char *ptr;
  25     const char *filename;
  26
  27     if (ac == 1) {
  28         fprintf(stderr, "%s filesize[k,m]\n", av[0]);
  29         exit(1);
  30     }
  31     bytes = strtol(av[1], &ptr, 0);
  32     if (*ptr == 'k' || *ptr == 'K') {
  33         bytes *= 1024;
  34     } else if (*ptr == 'm' || *ptr == 'M') {
  35         bytes *= 1024 * 1024;
  36     } else if (*ptr) {
  37         fprintf(stderr, "Illegal numerical suffix: %s\n", ptr);
  38         exit(1);
  39     }
  40     if (bytes <= 0) {
  41         fprintf(stderr, "I can't handle %d sized buffers\n", bytes);
  42         exit(1);
  43     }
  44
  45     filename = "read1.dat";
  46     fd = open(filename, O_RDWR|O_CREAT|O_TRUNC, 0666);
  47     if (fd < 0) {
  48         if (errno == EROFS) {
  49             filename = "/tmp/read1.dat";
  50             fd = open(filename, O_RDWR|O_CREAT|O_TRUNC, 0666);
  51         }
  52         if (fd < 0) {
  53             perror("open()");
  54             exit(1);
  55         }
  56     }
  57     for (i = 0; i < bytes; i += sizeof(Buf)) {
  58         int n = (bytes - i > sizeof(Buf)) ? sizeof(Buf) : bytes - i;
  59         if (write(fd, Buf, n) != n) {
  60             close(fd);
  61             perror("write()");
  62             remove(filename);
  63             exit(1);
  64         }
  65     }
  66     fsync(fd);
  67     fsync(fd);
  68     sleep(1);
  69     fsync(fd);
  70     lseek(fd, 0L, 0);
  71     sleep(1);
  72
  73     start_timing();
  74     i = 0;
  75     while (stop_timing(0, NULL) == 0) {
  76         for (j = 0; j < 256 * 1024; ++j) {
  77             if (read(fd, &c, 1) != 1)
  78                 lseek(fd, 0L, 0);
  79         }
  80         i += j;
  81     }
  82     lseek(fd, 0L, 0);
  83     start_timing();
  84     for (j = 0; j < i; ++j) {
  85         if (read(fd, &c, 1) != 1)
  86             lseek(fd, 0L, 0);
  87     }
  88     stop_timing(j, "read 1char from file:");
  89     remove(filename);
  90     return(0);
  91 }
  92