/* Copyright Joyent, Inc. and other Node contributors. All rights reserved.

 *

 * Permission is hereby granted, free of charge, to any person obtaining a copy

 * of this software and associated documentation files (the "Software"), to

 * deal in the Software without restriction, including without limitation the

 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or

 * sell copies of the Software, and to permit persons to whom the Software is

 * furnished to do so, subject to the following conditions:

 *

 * The above copyright notice and this permission notice shall be included in

 * all copies or substantial portions of the Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING

 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS

 * IN THE SOFTWARE.

 */

#include "task.h"

#include "uv.h"

#include <stdio.h>

#include <stdlib.h>

#define NUM_SYNC_REQS         (10 * 1e5)

#define NUM_ASYNC_REQS        (1 * (int) 1e5)

#define MAX_CONCURRENT_REQS   32

#define sync_stat(req, path)                                                  \

  do {                                                                        \

    uv_fs_stat(NULL, (req), (path), NULL);                                    \

    uv_fs_req_cleanup((req));                                                 \

  }                                                                           \

  while (0)

struct async_req {

  const char* path;

  uv_fs_t fs_req;

  int* count;

};

static void warmup(const char* path) {

  uv_fs_t reqs[MAX_CONCURRENT_REQS];

  unsigned int i;

  /* warm up the thread pool */

  for (i = 0; i < ARRAY_SIZE(reqs); i++)

    uv_fs_stat(uv_default_loop(), reqs + i, path, uv_fs_req_cleanup);

  uv_run(uv_default_loop(), UV_RUN_DEFAULT);

  /* warm up the OS dirent cache */

  for (i = 0; i < 16; i++)

    sync_stat(reqs + 0, path);

}

static void sync_bench(const char* path) {

  uint64_t before;

  uint64_t after;

  uv_fs_t req;

  int i;

  /* do the sync benchmark */

  before = uv_hrtime();

  for (i = 0; i < NUM_SYNC_REQS; i++)

    sync_stat(&req, path);

  after = uv_hrtime();

  printf("%s stats (sync): %.2fs (%s/s)\n",

         fmt(1.0 * NUM_SYNC_REQS),

         (after - before) / 1e9,

         fmt((1.0 * NUM_SYNC_REQS) / ((after - before) / 1e9)));

  fflush(stdout);

}

static void stat_cb(uv_fs_t* fs_req) {

  struct async_req* req = container_of(fs_req, struct async_req, fs_req);

  uv_fs_req_cleanup(&req->fs_req);

  if (*req->count == 0) return;

  uv_fs_stat(uv_default_loop(), &req->fs_req, req->path, stat_cb);

  (*req->count)--;

}

static void async_bench(const char* path) {

  struct async_req reqs[MAX_CONCURRENT_REQS];

  struct async_req* req;

  uint64_t before;

  uint64_t after;

  int count;

  int i;

  for (i = 1; i <= MAX_CONCURRENT_REQS; i++) {

    count = NUM_ASYNC_REQS;

    for (req = reqs; req < reqs + i; req++) {

      req->path = path;

      req->count = &count;

      uv_fs_stat(uv_default_loop(), &req->fs_req, req->path, stat_cb);

    }

    before = uv_hrtime();

    uv_run(uv_default_loop(), UV_RUN_DEFAULT);

    after = uv_hrtime();

    printf("%s stats (%d concurrent): %.2fs (%s/s)\n",

           fmt(1.0 * NUM_ASYNC_REQS),

           i,

           (after - before) / 1e9,

           fmt((1.0 * NUM_ASYNC_REQS) / ((after - before) / 1e9)));

    fflush(stdout);

  }

}

/* This benchmark aims to measure the overhead of doing I/O syscalls from

 * the thread pool. The stat() syscall was chosen because its results are

 * easy for the operating system to cache, taking the actual I/O overhead

 * out of the equation.

 */

BENCHMARK_IMPL(fs_stat) {

  const char path[] = ".";

  warmup(path);

  sync_bench(path);

  async_bench(path);

  MAKE_VALGRIND_HAPPY();

  return 0;

}