text: /*
   *
   * sched-messaging.c
   *
   * messaging: Benchmark for scheduler and IPC mechanisms
   *
   * Based on hackbench by Rusty Russell <rusty@rustcorp.com.au>
   * Ported to perf by Hitoshi Mitake <mitake@dcl.info.waseda.ac.jp>
   *
   */
  
  #include "../perf.h"
  #include "../util/util.h"
  #include "../util/parse-options.h"
  #include "../builtin.h"
  #include "bench.h"
  
  /* Test groups of 20 processes spraying to 20 receivers */
  #include <pthread.h>
  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  #include <errno.h>
  #include <unistd.h>
  #include <sys/types.h>
  #include <sys/socket.h>
  #include <sys/wait.h>
  #include <sys/time.h>
  #include <sys/poll.h>
  #include <limits.h>
  
  #define DATASIZE 100
  
  static bool use_pipes = false;
  static unsigned int loops = 100;
  static bool thread_mode = false;
  static unsigned int num_groups = 10;
  
  struct sender_context {
  	unsigned int num_fds;
  	int ready_out;
  	int wakefd;
  	int out_fds[0];
  };
  
  struct receiver_context {
  	unsigned int num_packets;
  	int in_fds[2];
  	int ready_out;
  	int wakefd;
  };
  
  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(use_pipes ? "pipe()" : "socketpair()");
  }
  
  /* 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(struct sender_context *ctx)
  {
  	char data[DATASIZE];
  	unsigned int i, j;
  
  	ready(ctx->ready_out, ctx->wakefd);
  
  	/* Now pump to every receiver. */
  	for (i = 0; i < loops; i++) {
  		for (j = 0; j < ctx->num_fds; j++) {
  			int ret, done = 0;
  
  again:
  			ret = write(ctx->out_fds[j], data + done,
  				    sizeof(data)-done);
  			if (ret < 0)
  				barf("SENDER: write");
  			done += ret;
  			if (done < DATASIZE)
  				goto again;
  		}
  	}
  
  	return NULL;
  }
  
  
  /* One receiver per fd */
  static void *receiver(struct receiver_context* ctx)
  {
  	unsigned int i;
  
  	if (!thread_mode)
  		close(ctx->in_fds[1]);
  
  	/* Wait for start... */
  	ready(ctx->ready_out, ctx->wakefd);
  
  	/* Receive them all */
  	for (i = 0; i < ctx->num_packets; i++) {
  		char data[DATASIZE];
  		int ret, done = 0;
  
  again:
  		ret = read(ctx->in_fds[0], data + done, DATASIZE - done);
  		if (ret < 0)
  			barf("SERVER: read");
  		done += ret;
  		if (done < DATASIZE)
  			goto again;
  	}
  
  	return NULL;
  }
  
  static pthread_t create_worker(void *ctx, void *(*func)(void *))
  {
  	pthread_attr_t attr;
  	pthread_t childid;
  	int err;
  
  	if (!thread_mode) {
  		/* process mode */
  		/* Fork the receiver. */
  		switch (fork()) {
  		case -1:
  			barf("fork()");
  			break;
  		case 0:
  			(*func) (ctx);
  			exit(0);
  			break;
  		default:
  			break;
  		}
  
  		return (pthread_t)0;
  	}
  
  	if (pthread_attr_init(&attr) != 0)
  		barf("pthread_attr_init:");
  
  #ifndef __ia64__
  	if (pthread_attr_setstacksize(&attr, PTHREAD_STACK_MIN) != 0)
  		barf("pthread_attr_setstacksize");
  #endif
  
  	err = pthread_create(&childid, &attr, func, ctx);
  	if (err != 0) {
  		fprintf(stderr, "pthread_create failed: %s (%d)\n",
  			strerror(err), err);
  		exit(-1);
  	}
  	return childid;
  }
  
  static void reap_worker(pthread_t id)
  {
  	int proc_status;
  	void *thread_status;
  
  	if (!thread_mode) {
  		/* process mode */
  		wait(&proc_status);
  		if (!WIFEXITED(proc_status))
  			exit(1);
  	} else {
  		pthread_join(id, &thread_status);
  	}
  }
  
  /* One group of senders and receivers */
  static unsigned int group(pthread_t *pth,
  		unsigned int num_fds,
  		int ready_out,
  		int wakefd)
  {
  	unsigned int i;
  	struct sender_context *snd_ctx = malloc(sizeof(struct sender_context)
  			+ num_fds * sizeof(int));
  
  	if (!snd_ctx)
  		barf("malloc()");
  
  	for (i = 0; i < num_fds; i++) {
  		int fds[2];
  		struct receiver_context *ctx = malloc(sizeof(*ctx));
  
  		if (!ctx)
  			barf("malloc()");
  
  
  		/* Create the pipe between client and server */
  		fdpair(fds);
  
  		ctx->num_packets = num_fds * loops;
  		ctx->in_fds[0] = fds[0];
  		ctx->in_fds[1] = fds[1];
  		ctx->ready_out = ready_out;
  		ctx->wakefd = wakefd;
  
  		pth[i] = create_worker(ctx, (void *)receiver);
  
  		snd_ctx->out_fds[i] = fds[1];
  		if (!thread_mode)
  			close(fds[0]);
  	}
  
  	/* Now we have all the fds, fork the senders */
  	for (i = 0; i < num_fds; i++) {
  		snd_ctx->ready_out = ready_out;
  		snd_ctx->wakefd = wakefd;
  		snd_ctx->num_fds = num_fds;
  
  		pth[num_fds+i] = create_worker(snd_ctx, (void *)sender);
  	}
  
  	/* Close the fds we have left */
  	if (!thread_mode)
  		for (i = 0; i < num_fds; i++)
  			close(snd_ctx->out_fds[i]);
  
  	/* Return number of children to reap */
  	return num_fds * 2;
  }
  
  static const struct option options[] = {
  	OPT_BOOLEAN('p', "pipe", &use_pipes,
  		    "Use pipe() instead of socketpair()"),
  	OPT_BOOLEAN('t', "thread", &thread_mode,
  		    "Be multi thread instead of multi process"),
  	OPT_UINTEGER('g', "group", &num_groups, "Specify number of groups"),
  	OPT_UINTEGER('l', "loop", &loops, "Specify number of loops"),
  	OPT_END()
  };
  
  static const char * const bench_sched_message_usage[] = {
  	"perf bench sched messaging <options>",
  	NULL
  };
  
  int bench_sched_messaging(int argc, const char **argv,
  		    const char *prefix __used)
  {
  	unsigned int i, total_children;
  	struct timeval start, stop, diff;
  	unsigned int num_fds = 20;
  	int readyfds[2], wakefds[2];
  	char dummy;
  	pthread_t *pth_tab;
  
  	argc = parse_options(argc, argv, options,
  			     bench_sched_message_usage, 0);
  
  	pth_tab = malloc(num_fds * 2 * num_groups * sizeof(pthread_t));
  	if (!pth_tab)
  		barf("main:malloc()");
  
  	fdpair(readyfds);
  	fdpair(wakefds);
  
  	total_children = 0;
  	for (i = 0; i < num_groups; i++)
  		total_children += group(pth_tab+total_children, 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++)
  		reap_worker(pth_tab[i]);
  
  	gettimeofday(&stop, NULL);
  
  	timersub(&stop, &start, &diff);
  
  	switch (bench_format) {
  	case BENCH_FORMAT_DEFAULT:
  		printf("# %d sender and receiver %s per group\n",
  		       num_fds, thread_mode ? "threads" : "processes");
  		printf("# %d groups == %d %s run\n\n",
  		       num_groups, num_groups * 2 * num_fds,
  		       thread_mode ? "threads" : "processes");
  		printf(" %14s: %lu.%03lu [sec]\n", "Total time",
  		       diff.tv_sec,
  		       (unsigned long) (diff.tv_usec/1000));
  		break;
  	case BENCH_FORMAT_SIMPLE:
  		printf("%lu.%03lu\n", diff.tv_sec,
  		       (unsigned long) (diff.tv_usec/1000));
  		break;
  	default:
  		/* reaching here is something disaster */
  		fprintf(stderr, "Unknown format:%d\n", bench_format);
  		exit(1);
  		break;
  	}
  
  	return 0;
  }
  