+/* Test groups of 20 processes spraying to 20 receivers */
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/wait.h>
+#include <sys/time.h>
+#include <sys/poll.h>
+
+#define DATASIZE 100
+static unsigned int loops = 100;
+static int use_pipes = 0;
+
+static void barf(const char *msg)
+{
+ fprintf(stderr, "%s (error: %s)\n", msg, strerror(errno));
+ exit(1);
+}
+
+static void fdpair(int fds[2])
+{
+ if (use_pipes) {
+ if (pipe(fds) == 0)
+ return;
+ } else {
+ if (socketpair(AF_UNIX, SOCK_STREAM, 0, fds) == 0)
+ return;
+ }
+ barf("Creating fdpair");
+}
+
+/* Block until we're ready to go */
+static void ready(int ready_out, int wakefd)
+{
+ char dummy;
+ struct pollfd pollfd = { .fd = wakefd, .events = POLLIN };
+
+ /* Tell them we're ready. */
+ if (write(ready_out, &dummy, 1) != 1)
+ barf("CLIENT: ready write");
+
+ /* Wait for "GO" signal */
+ if (poll(&pollfd, 1, -1) != 1)
+ barf("poll");
+}
+
+/* Sender sprays loops messages down each file descriptor */
+static void sender(unsigned int num_fds,
+ int out_fd[num_fds],
+ int ready_out,
+ int wakefd)
+{
+ char data[DATASIZE];
+ unsigned int i, j;
+
+ ready(ready_out, wakefd);
+
+ /* Now pump to every receiver. */
+ for (i = 0; i < loops; i++) {
+ for (j = 0; j < num_fds; j++) {
+ int ret, done = 0;
+
+ again:
+ ret = write(out_fd[j], data + done, sizeof(data)-done);
+ if (ret < 0)
+ barf("SENDER: write");
+ done += ret;
+ if (done < sizeof(data))
+ goto again;
+ }
+ }
+}
+
+/* One receiver per fd */
+static void receiver(unsigned int num_packets,
+ int in_fd,
+ int ready_out,
+ int wakefd)
+{
+ unsigned int i;
+
+ /* Wait for start... */
+ ready(ready_out, wakefd);
+
+ /* Receive them all */
+ for (i = 0; i < num_packets; i++) {
+ char data[DATASIZE];
+ int ret, done = 0;
+
+ again:
+ ret = read(in_fd, data + done, DATASIZE - done);
+ if (ret < 0)
+ barf("SERVER: read");
+ done += ret;
+ if (done < DATASIZE)
+ goto again;
+ }
+}
+
+/* One group of senders and receivers */
+static unsigned int group(unsigned int num_fds,
+ int ready_out,
+ int wakefd)
+{
+ unsigned int i;
+ unsigned int out_fds[num_fds];
+
+ for (i = 0; i < num_fds; i++) {
+ int fds[2];
+
+ /* Create the pipe between client and server */
+ fdpair(fds);
+
+ /* Fork the receiver. */
+ switch (fork()) {
+ case -1: barf("fork()");
+ case 0:
+ close(fds[1]);
+ receiver(num_fds*loops, fds[0], ready_out, wakefd);
+ exit(0);
+ }
+
+ out_fds[i] = fds[1];
+ close(fds[0]);
+ }
+
+ /* Now we have all the fds, fork the senders */
+ for (i = 0; i < num_fds; i++) {
+ switch (fork()) {
+ case -1: barf("fork()");
+ case 0:
+ sender(num_fds, out_fds, ready_out, wakefd);
+ exit(0);
+ }
+ }
+
+ /* Close the fds we have left */
+ for (i = 0; i < num_fds; i++)
+ close(out_fds[i]);
+
+ /* Return number of children to reap */
+ return num_fds * 2;
+}
+
+int main(int argc, char *argv[])
+{
+ unsigned int i, num_groups, total_children;
+ struct timeval start, stop, diff;
+ unsigned int num_fds = 20;
+ int readyfds[2], wakefds[2];
+ char dummy;
+
+ if (argv[1] && strcmp(argv[1], "-pipe") == 0) {
+ use_pipes = 1;
+ argc--;
+ argv++;
+ }
+
+ if (argc != 2 || (num_groups = atoi(argv[1])) == 0)
+ barf("Usage: hackbench [-pipe] <num groups>\n");
+
+ fdpair(readyfds);
+ fdpair(wakefds);
+
+ total_children = 0;
+ for (i = 0; i < num_groups; i++)
+ total_children += group(num_fds, readyfds[1], wakefds[0]);
+
+ /* Wait for everyone to be ready */
+ for (i = 0; i < total_children; i++)
+ if (read(readyfds[0], &dummy, 1) != 1)
+ barf("Reading for readyfds");
+
+ gettimeofday(&start, NULL);
+
+ /* Kick them off */
+ if (write(wakefds[1], &dummy, 1) != 1)
+ barf("Writing to start them");
+
+ /* Reap them all */
+ for (i = 0; i < total_children; i++) {
+ int status;
+ wait(&status);
+ if (!WIFEXITED(status))
+ exit(1);
+ }
+
+ gettimeofday(&stop, NULL);
+
+ /* Print time... */
+ timersub(&stop, &start, &diff);
+ printf("Time: %lu.%03lu\n", diff.tv_sec, diff.tv_usec/1000);
+ exit(0);
+}