test/sysperf/pipe2.c

   1 /*
   2  * pipe2.c
   3  */
   4 #include <sys/types.h>
   5 #include <sys/wait.h>
   6 #include <sys/resource.h>
   7 #include "blib.h"
   8
   9 #define PAGE_SIZE       4096
  10 #define PAGE_MASK       (PAGE_SIZE - 1)
  11
  12 int
  13 main(int ac, char **av)
  14 {
  15     long long count = 0;
  16     long long max;
  17     char c;
  18     int j;
  19     int loops;
  20     int bytes;
  21     int ppri = 999;
  22     int fds[2];
  23     char *buf;
  24     char *ptr;
  25     char *msg = "datarate";
  26
  27     if (ac == 1) {
  28         fprintf(stderr, "%s blocksize[k,m] [pipe_writer_pri] [msg]\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     if (ac >= 3)
  45         ppri = strtol(av[2], NULL, 0);
  46     if (ac >= 4)
  47         msg = av[3];
  48
  49     buf = mmap(NULL, bytes * 2 + PAGE_SIZE,
  50                PROT_READ|PROT_WRITE, MAP_SHARED|MAP_ANON, -1, 0);
  51     if (buf == MAP_FAILED) {
  52         perror("mmap/buffer");
  53         exit(1);
  54     }
  55
  56     bzero(buf, bytes * 2 + PAGE_SIZE);
  57
  58     printf("tests one-way pipe using direct-write buffer\n");
  59     if (pipe(fds)) {
  60         perror("pipe");
  61         exit(1);
  62     }
  63     if (fork() == 0) {
  64         /*
  65          * child process
  66          */
  67         int n;
  68         int i;
  69
  70         close(fds[0]);
  71         buf += (bytes + PAGE_MASK) & ~PAGE_MASK;
  72         i = 0;
  73         for (;;) {
  74             n = read(fds[1], buf + i, bytes - i);
  75             if (n <= 0)
  76                 break;
  77             if (n + i == bytes)
  78                 i = 0;
  79             else
  80                 i += n;
  81         }
  82         _exit(0);
  83     } else {
  84         /*
  85          * parent process.
  86          */
  87         if (ppri != 999) {
  88             if (setpriority(PRIO_PROCESS, getpid(), ppri) < 0) {
  89                 perror("setpriority");
  90                 exit(1);
  91             }
  92         }
  93         close(fds[1]);
  94
  95         /*
  96          * Figure out how many loops it takes for 1 second's worth.
  97          */
  98         start_timing();
  99         for (j = 0; ; ++j) {
 100             if (write(fds[0], buf, bytes) != bytes) {
 101                 perror("write");
 102                 exit(1);
 103             }
 104             if ((j & 31) == 0 && stop_timing(0, NULL))
 105                 break;
 106         }
 107         loops = j * 2 + 1;
 108         loops *= 2;
 109         usleep(1000000 / 10);
 110         start_timing();
 111
 112         for (j = loops; j; --j) {
 113             if (write(fds[0], buf, bytes) != bytes) {
 114                 perror("write");
 115                 exit(1);
 116             }
 117         }
 118         close(fds[0]);
 119         while(wait(NULL) >= 0)
 120             ;
 121         stop_timing(loops, "full duplex pipe / %dK bufs:", bytes / 1024);
 122         printf("%s: blkSize %d %5.2f MBytes/sec\n",
 123                 msg,
 124                 bytes,
 125                 (double)loops * bytes * 1000000.0 /
 126                 (1024.0 * 1024.0 * get_timing()));
 127     }
 128     return(0);
 129 }
 130