hackbench.c

   1 /* Test groups of 20 processes spraying to 20 receivers */
   2 #include <stdio.h>
   3 #include <string.h>
   4 #include <errno.h>
   5 #include <sys/types.h>
   6 #include <sys/socket.h>
   7 #include <sys/wait.h>
   8 #include <sys/time.h>
   9 #include <sys/poll.h>
  10
  11 #define DATASIZE 100
  12 static unsigned int loops = 100;
  13 static int use_pipes = 0;
  14
  15 static void barf(const char *msg)
  16 {
  17         fprintf(stderr, "%s (error: %s)\n", msg, strerror(errno));
  18         exit(1);
  19 }
  20
  21 static void fdpair(int fds[2])
  22 {
  23         if (use_pipes) {
  24                 if (pipe(fds) == 0)
  25                         return;
  26         } else {
  27                 if (socketpair(AF_UNIX, SOCK_STREAM, 0, fds) == 0)
  28                         return;
  29         }
  30         barf("Creating fdpair");
  31 }
  32
  33 /* Block until we're ready to go */
  34 static void ready(int ready_out, int wakefd)
  35 {
  36         char dummy;
  37         struct pollfd pollfd = { .fd = wakefd, .events = POLLIN };
  38
  39         /* Tell them we're ready. */
  40         if (write(ready_out, &dummy, 1) != 1)
  41                 barf("CLIENT: ready write");
  42
  43         /* Wait for "GO" signal */
  44         if (poll(&pollfd, 1, -1) != 1)
  45                 barf("poll");
  46 }
  47
  48 /* Sender sprays loops messages down each file descriptor */
  49 static void sender(unsigned int num_fds,
  50                    int out_fd[num_fds],
  51                    int ready_out,
  52                    int wakefd)
  53 {
  54         char data[DATASIZE];
  55         unsigned int i, j;
  56
  57         ready(ready_out, wakefd);
  58
  59         /* Now pump to every receiver. */
  60         for (i = 0; i < loops; i++) {
  61                 for (j = 0; j < num_fds; j++) {
  62                         int ret, done = 0;
  63
  64                 again:
  65                         ret = write(out_fd[j], data + done, sizeof(data)-done);
  66                         if (ret < 0)
  67                                 barf("SENDER: write");
  68                         done += ret;
  69                         if (done < sizeof(data))
  70                                 goto again;
  71                 }
  72         }
  73 }
  74
  75 /* One receiver per fd */
  76 static void receiver(unsigned int num_packets,
  77                      int in_fd,
  78                      int ready_out,
  79                      int wakefd)
  80 {
  81         unsigned int i;
  82
  83         /* Wait for start... */
  84         ready(ready_out, wakefd);
  85
  86         /* Receive them all */
  87         for (i = 0; i < num_packets; i++) {
  88                 char data[DATASIZE];
  89                 int ret, done = 0;
  90
  91         again:
  92                 ret = read(in_fd, data + done, DATASIZE - done);
  93                 if (ret < 0)
  94                         barf("SERVER: read");
  95                 done += ret;
  96                 if (done < DATASIZE)
  97                         goto again;
  98         }
  99 }
 100
 101 /* One group of senders and receivers */
 102 static unsigned int group(unsigned int num_fds,
 103                           int ready_out,
 104                           int wakefd)
 105 {
 106         unsigned int i;
 107         unsigned int out_fds[num_fds];
 108
 109         for (i = 0; i < num_fds; i++) {
 110                 int fds[2];
 111
 112                 /* Create the pipe between client and server */
 113                 fdpair(fds);
 114
 115                 /* Fork the receiver. */
 116                 switch (fork()) {
 117                 case -1: barf("fork()");
 118                 case 0:
 119                         close(fds[1]);
 120                         receiver(num_fds*loops, fds[0], ready_out, wakefd);
 121                         exit(0);
 122                 }
 123
 124                 out_fds[i] = fds[1];
 125                 close(fds[0]);
 126         }
 127
 128         /* Now we have all the fds, fork the senders */
 129         for (i = 0; i < num_fds; i++) {
 130                 switch (fork()) {
 131                 case -1: barf("fork()");
 132                 case 0:
 133                         sender(num_fds, out_fds, ready_out, wakefd);
 134                         exit(0);
 135                 }
 136         }
 137
 138         /* Close the fds we have left */
 139         for (i = 0; i < num_fds; i++)
 140                 close(out_fds[i]);
 141
 142         /* Return number of children to reap */
 143         return num_fds * 2;
 144 }
 145
 146 int main(int argc, char *argv[])
 147 {
 148         unsigned int i, num_groups, total_children;
 149         struct timeval start, stop, diff;
 150         unsigned int num_fds = 20;
 151         int readyfds[2], wakefds[2];
 152         char dummy;
 153
 154         if (argv[1] && strcmp(argv[1], "-pipe") == 0) {
 155                 use_pipes = 1;
 156                 argc--;
 157                 argv++;
 158         }
 159
 160         if (argc != 2 || (num_groups = atoi(argv[1])) == 0)
 161                 barf("Usage: hackbench [-pipe] <num groups>\n");
 162
 163         fdpair(readyfds);
 164         fdpair(wakefds);
 165
 166         total_children = 0;
 167         for (i = 0; i < num_groups; i++)
 168                 total_children += group(num_fds, readyfds[1], wakefds[0]);
 169
 170         /* Wait for everyone to be ready */
 171         for (i = 0; i < total_children; i++)
 172                 if (read(readyfds[0], &dummy, 1) != 1)
 173                         barf("Reading for readyfds");
 174
 175         gettimeofday(&start, NULL);
 176
 177         /* Kick them off */
 178         if (write(wakefds[1], &dummy, 1) != 1)
 179                 barf("Writing to start them");
 180
 181         /* Reap them all */
 182         for (i = 0; i < total_children; i++) {
 183                 int status;
 184                 wait(&status);
 185                 if (!WIFEXITED(status))
 186                         exit(1);
 187         }
 188
 189         gettimeofday(&stop, NULL);
 190
 191         /* Print time... */
 192         timersub(&stop, &start, &diff);
 193         printf("Time: %lu.%03lu\n", diff.tv_sec, diff.tv_usec/1000);
 194         exit(0);
 195 }