task_ans.c

/*
 * Licensed to the OpenAirInterface (OAI) Software Alliance under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The OpenAirInterface Software Alliance licenses this file to You under
 * the OAI Public License, Version 1.1  (the "License"); you may not use this file
 * except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.openairinterface.org/?page_id=698
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *-------------------------------------------------------------------------------
 * For more information about the OpenAirInterface (OAI) Software Alliance:
 *      contact@openairinterface.org
 */

#include "task_ans.h"
#include "assertions.h"
#include <limits.h>
#include <stddef.h>
#include <stdint.h>
#include <stdlib.h>
#include <time.h>

void completed_task_ans(task_ans_t* task)
{
  DevAssert(task != NULL);

  if (atomic_load_explicit(&task->status, memory_order_acquire) != 0)
    AssertFatal(0, "Task already finished?");

  atomic_store_explicit(&task->status, 1, memory_order_release);
}

void join_task_ans(task_ans_t* arr, size_t len)
{
  DevAssert(len < INT_MAX);
  DevAssert(arr != NULL);

  // Spin lock inspired by:
  // The Art of Writing Efficient Programs:
  // An advanced programmer's guide to efficient hardware utilization
  // and compiler optimizations using C++ examples
  const struct timespec ns = {0, 1};
  uint64_t i = 0;
  int j = len - 1;
  for (; j != -1; i++) {
    for (; j != -1; --j) {
      int const task_completed = 1;
      if (atomic_load_explicit(&arr[j].status, memory_order_acquire) != task_completed)
        break;
    }
    if (i % 8 == 0) {
      nanosleep(&ns, NULL);
    }
  }
}