// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2015 Davidlohr Bueso.
 */

/* For the CLR_() macros */
#include <string.h>
#include <pthread.h>

#include <signal.h>
#include "../util/stat.h"
#include <subcmd/parse-options.h>
#include <linux/compiler.h>
#include <linux/kernel.h>
#include <linux/zalloc.h>
#include <errno.h>
#include <perf/cpumap.h>
#include "bench.h"
#include "futex.h"

#include <err.h>
#include <stdlib.h>
#include <sys/time.h>
#include <sys/mman.h>

struct worker {
        int tid;
        u_int32_t *futex;
        pthread_t thread;
        unsigned long ops;
};

static u_int32_t global_futex = 0;
static struct worker *worker;
static bool done = false;
static int futex_flag = 0;
static pthread_mutex_t thread_lock;
static unsigned int threads_starting;
static struct stats throughput_stats;
static pthread_cond_t thread_parent, thread_worker;

static struct bench_futex_parameters params = {
        .runtime  = 10,
};

static const struct option options[] = {
        OPT_UINTEGER('t', "threads", &params.nthreads, "Specify amount of threads"),
        OPT_UINTEGER('r', "runtime", &params.runtime, "Specify runtime (in seconds)"),
        OPT_BOOLEAN( 'M', "multi",   &params.multi, "Use multiple futexes"),
        OPT_BOOLEAN( 's', "silent",  &params.silent, "Silent mode: do not display data/details"),
        OPT_BOOLEAN( 'S', "shared",  &params.fshared, "Use shared futexes instead of private ones"),
        OPT_BOOLEAN( 'm', "mlockall", &params.mlockall, "Lock all current and future memory"),
        OPT_END()
};

static const char * const bench_futex_lock_pi_usage[] = {
        "perf bench futex lock-pi <options>",
        NULL
};

static void print_summary(void)
{
        unsigned long avg = avg_stats(&throughput_stats);
        double stddev = stddev_stats(&throughput_stats);

        printf("%sAveraged %ld operations/sec (+- %.2f%%), total secs = %d\n",
               !params.silent ? "\n" : "", avg, rel_stddev_stats(stddev, avg),
               (int)bench__runtime.tv_sec);
}

static void toggle_done(int sig __maybe_unused,
                        siginfo_t *info __maybe_unused,
                        void *uc __maybe_unused)
{
        /* inform all threads that we're done for the day */
        done = true;
        gettimeofday(&bench__end, NULL);
        timersub(&bench__end, &bench__start, &bench__runtime);
}

static void *workerfn(void *arg)
{
        struct worker *w = (struct worker *) arg;
        unsigned long ops = w->ops;

        pthread_mutex_lock(&thread_lock);
        threads_starting--;
        if (!threads_starting)
                pthread_cond_signal(&thread_parent);
        pthread_cond_wait(&thread_worker, &thread_lock);
        pthread_mutex_unlock(&thread_lock);

        do {
                int ret;
        again:
                ret = futex_lock_pi(w->futex, NULL, futex_flag);

                if (ret) { /* handle lock acquisition */
                        if (!params.silent)
                                warn("thread %d: Could not lock pi-lock for %p (%d)",
                                     w->tid, w->futex, ret);
                        if (done)
                                break;

                        goto again;
                }

                usleep(1);
                ret = futex_unlock_pi(w->futex, futex_flag);
                if (ret && !params.silent)
                        warn("thread %d: Could not unlock pi-lock for %p (%d)",
                             w->tid, w->futex, ret);
                ops++; /* account for thread's share of work */
        }  while (!done);

        w->ops = ops;
        return NULL;
}

static void create_threads(struct worker *w, pthread_attr_t thread_attr,
                           struct perf_cpu_map *cpu)
{
        cpu_set_t cpuset;
        unsigned int i;

        threads_starting = params.nthreads;

        for (i = 0; i < params.nthreads; i++) {
                worker[i].tid = i;

                if (params.multi) {
                        worker[i].futex = calloc(1, sizeof(u_int32_t));
                        if (!worker[i].futex)
                                err(EXIT_FAILURE, "calloc");
                } else
                        worker[i].futex = &global_futex;

                CPU_ZERO(&cpuset);
                CPU_SET(cpu->map[i % cpu->nr], &cpuset);

                if (pthread_attr_setaffinity_np(&thread_attr, sizeof(cpu_set_t), &cpuset))
                        err(EXIT_FAILURE, "pthread_attr_setaffinity_np");

                if (pthread_create(&w[i].thread, &thread_attr, workerfn, &worker[i]))
                        err(EXIT_FAILURE, "pthread_create");
        }
}

int bench_futex_lock_pi(int argc, const char **argv)
{
        int ret = 0;
        unsigned int i;
        struct sigaction act;
        pthread_attr_t thread_attr;
        struct perf_cpu_map *cpu;

        argc = parse_options(argc, argv, options, bench_futex_lock_pi_usage, 0);
        if (argc)
                goto err;

        cpu = perf_cpu_map__new(NULL);
        if (!cpu)
                err(EXIT_FAILURE, "calloc");

        memset(&act, 0, sizeof(act));
        sigfillset(&act.sa_mask);
        act.sa_sigaction = toggle_done;
        sigaction(SIGINT, &act, NULL);

        if (params.mlockall) {
                if (mlockall(MCL_CURRENT | MCL_FUTURE))
                        err(EXIT_FAILURE, "mlockall");
        }

        if (!params.nthreads)
                params.nthreads = cpu->nr;

        worker = calloc(params.nthreads, sizeof(*worker));
        if (!worker)
                err(EXIT_FAILURE, "calloc");

        if (!params.fshared)
                futex_flag = FUTEX_PRIVATE_FLAG;

        printf("Run summary [PID %d]: %d threads doing pi lock/unlock pairing for %d secs.\n\n",
               getpid(), params.nthreads, params.runtime);

        init_stats(&throughput_stats);
        pthread_mutex_init(&thread_lock, NULL);
        pthread_cond_init(&thread_parent, NULL);
        pthread_cond_init(&thread_worker, NULL);

        threads_starting = params.nthreads;
        pthread_attr_init(&thread_attr);
        gettimeofday(&bench__start, NULL);

        create_threads(worker, thread_attr, cpu);
        pthread_attr_destroy(&thread_attr);

        pthread_mutex_lock(&thread_lock);
        while (threads_starting)
                pthread_cond_wait(&thread_parent, &thread_lock);
        pthread_cond_broadcast(&thread_worker);
        pthread_mutex_unlock(&thread_lock);

        sleep(params.runtime);
        toggle_done(0, NULL, NULL);

        for (i = 0; i < params.nthreads; i++) {
                ret = pthread_join(worker[i].thread, NULL);
                if (ret)
                        err(EXIT_FAILURE, "pthread_join");
        }

        /* cleanup & report results */
        pthread_cond_destroy(&thread_parent);
        pthread_cond_destroy(&thread_worker);
        pthread_mutex_destroy(&thread_lock);

        for (i = 0; i < params.nthreads; i++) {
                unsigned long t = bench__runtime.tv_sec > 0 ?
                        worker[i].ops / bench__runtime.tv_sec : 0;

                update_stats(&throughput_stats, t);
                if (!params.silent)
                        printf("[thread %3d] futex: %p [ %ld ops/sec ]\n",
                               worker[i].tid, worker[i].futex, t);

                if (params.multi)
                        zfree(&worker[i].futex);
        }

        print_summary();

        free(worker);
        perf_cpu_map__put(cpu);
        return ret;
err:
        usage_with_options(bench_futex_lock_pi_usage, options);
        exit(EXIT_FAILURE);
}