test/sysperf/randread.c

   1
   2 #include <sys/types.h>
   3 #include <sys/stat.h>
   4 #include <sys/file.h>
   5 #include <sys/errno.h>
   6 #include <sys/wait.h>
   7 #include <string.h>
   8 #include <stdio.h>
   9 #include <stdlib.h>
  10 #include <unistd.h>
  11 #include <machine/atomic.h>
  12 #include "blib.h"
  13
  14 int
  15 main(int ac, char **av)
  16 {
  17     char *buf;
  18     size_t bytes = 512;
  19     off_t limit;
  20     int fd;
  21     int i;
  22     int nprocs = 32;
  23     double range = 90.0;
  24     volatile int *counterp;
  25     int clast;
  26     int cnext;
  27     int cdelta;
  28
  29     if (ac < 2 || ac > 5) {
  30         fprintf(stderr, "%s <device> [bufsize:512 [range%:90 [nprocs:32]]]\n",
  31                 av[0]);
  32         exit (1);
  33     }
  34
  35     if (ac >= 3) {
  36         bytes = (size_t)strtoul(av[2], NULL, 0);
  37         if (bytes < 512 || (bytes ^ (bytes - 1)) != ((bytes << 1) - 1)) {
  38             fprintf(stderr, "bytes must be a power of 2 >= 512\n");
  39             exit (1);
  40         }
  41     }
  42     buf = malloc(bytes);
  43
  44     if (ac >= 4) {
  45         range = strtod(av[3], NULL);
  46     }
  47
  48     if (ac >= 5) {
  49         nprocs = strtol(av[4], NULL, 0);
  50         if (nprocs < 0 || nprocs > 512) {
  51             fprintf(stderr, "absurd nprocs (%d)\n", nprocs);
  52             exit(1);
  53         }
  54     }
  55
  56     fd = open(av[1], O_RDONLY);
  57     if (fd < 0) {
  58         fprintf(stderr, "open %s: %s\n", av[1], strerror(errno));
  59         exit (1);
  60     }
  61
  62     lseek(fd, 0L, 2);
  63     limit = lseek(fd, 0L, 1);
  64     limit = (off_t)((double)limit * range / 100.0);
  65     limit &= ~(off_t)(bytes - 1);
  66     printf("device %s bufsize %zd limit %4.3fGB nprocs %d\n",
  67         av[1], bytes, (double)limit / (1024.0*1024.0*1024.0), nprocs);
  68
  69     counterp = mmap(NULL, sizeof(int), PROT_READ|PROT_WRITE,
  70                     MAP_SHARED|MAP_ANON, -1, 0);
  71
  72     for (i = 0; i < nprocs; ++i) {
  73         if (fork() == 0) {
  74             close(fd);
  75             fd = open(av[1], O_RDONLY);
  76             srandomdev();
  77             for (;;) {
  78                 long pos;
  79
  80                 pos = random() ^ ((long)random() << 31);
  81                 pos &= 0x7FFFFFFFFFFFFFFFLLU;
  82                 pos = (pos % limit) & ~(off_t)(bytes - 1);
  83                 lseek(fd, pos, 0);
  84                 read(fd, buf, bytes);
  85                 atomic_add_int(counterp, 1);
  86             }
  87         }
  88     }
  89     start_timing();
  90     sleep(1);
  91     start_timing();
  92     clast = *counterp;
  93
  94     for (;;) {
  95         sleep(1);
  96         cnext = *counterp;
  97         cdelta = cnext - clast;
  98         clast = cnext;
  99         stop_timing(cdelta, "randread");
 100     }
 101     return 0;
 102 }