// SPDX-License-Identifier: GPL-2.0
/*
 *
 * 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 <subcmd/parse-options.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 <poll.h>
#include <limits.h>
#include <err.h>
#include <linux/time64.h>

#define DATASIZE 100

static bool use_pipes = false;
static unsigned int nr_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[];
};

struct receiver_context {
        unsigned int num_packets;
        int in_fds[2];
        int ready_out;
        int wakefd;
};

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;
        }

        err(EXIT_FAILURE, use_pipes ? "pipe()" : "socketpair()");
}

/* Block until we're ready to go */
static void ready(int ready_out, int wakefd)
{
        struct pollfd pollfd = { .fd = wakefd, .events = POLLIN };

        /* Tell them we're ready. */
        if (write(ready_out, "R", 1) != 1)
                err(EXIT_FAILURE, "CLIENT: ready write");

        /* Wait for "GO" signal */
        if (poll(&pollfd, 1, -1) != 1)
                err(EXIT_FAILURE, "poll");
}

/* Sender sprays nr_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);
        memset(data, 'S', sizeof(data));

        /* Now pump to every receiver. */
        for (i = 0; i < nr_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)
                                err(EXIT_FAILURE, "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)
                        err(EXIT_FAILURE, "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 ret;

        if (!thread_mode) {
                /* process mode */
                /* Fork the receiver. */
                switch (fork()) {
                case -1:
                        err(EXIT_FAILURE, "fork()");
                        break;
                case 0:
                        (*func) (ctx);
                        exit(0);
                        break;
                default:
                        break;
                }

                return (pthread_t)0;
        }

        if (pthread_attr_init(&attr) != 0)
                err(EXIT_FAILURE, "pthread_attr_init:");

#ifndef __ia64__
        if (pthread_attr_setstacksize(&attr, PTHREAD_STACK_MIN) != 0)
                err(EXIT_FAILURE, "pthread_attr_setstacksize");
#endif

        ret = pthread_create(&childid, &attr, func, ctx);
        if (ret != 0)
                err(EXIT_FAILURE, "pthread_create failed");

        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)
                err(EXIT_FAILURE, "malloc()");

        for (i = 0; i < num_fds; i++) {
                int fds[2];
                struct receiver_context *ctx = malloc(sizeof(*ctx));

                if (!ctx)
                        err(EXIT_FAILURE, "malloc()");


                /* Create the pipe between client and server */
                fdpair(fds);

                ctx->num_packets = num_fds * nr_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', "nr_loops", &nr_loops, "Specify the number of loops to run (default: 100)"),
        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)
{
        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)
                err(EXIT_FAILURE, "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)
                        err(EXIT_FAILURE, "Reading for readyfds");

        gettimeofday(&start, NULL);

        /* Kick them off */
        if (write(wakefds[1], &dummy, 1) != 1)
                err(EXIT_FAILURE, "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",
                       (unsigned long) diff.tv_sec,
                       (unsigned long) (diff.tv_usec / USEC_PER_MSEC));
                break;
        case BENCH_FORMAT_SIMPLE:
                printf("%lu.%03lu\n", (unsigned long) diff.tv_sec,
                       (unsigned long) (diff.tv_usec / USEC_PER_MSEC));
                break;
        default:
                /* reaching here is something disaster */
                fprintf(stderr, "Unknown format:%d\n", bench_format);
                exit(1);
                break;
        }

        free(pth_tab);

        return 0;
}