x15/test/test_semaphore.c

/*
 * Copyright (c) 2019 Richard Braun.
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 *
 * This test creates a number of threads (at least 2) which wait on a
 * semaphore, and one that posts the semaphore as many times as there
 * are threads. All threads are bound to the same processor, and posts
 * are performed with preemption disabled, to guarantee they occur
 * back-to-back in order to make sure that they're not missed.
 */

#include <stddef.h>
#include <stdio.h>

#include <kern/cpumap.h>
#include <kern/error.h>
#include <kern/log.h>
#include <kern/macros.h>
#include <kern/semaphore.h>
#include <kern/thread.h>
#include <test/test.h>

#define TEST_NR_WAITERS 2

#if TEST_NR_WAITERS < 2
  #error "invalid number of waiters"
#endif

static struct semaphore test_semaphore;

static struct thread *test_waiters[TEST_NR_WAITERS];

static void
test_wait (void *arg __unused)
{
  semaphore_wait (&test_semaphore);
}

static void
test_post (void *arg __unused)
{
  for (size_t i = 0; i < ARRAY_SIZE (test_waiters); i++)
    while (thread_state (test_waiters[i]) != THREAD_SLEEPING)
      thread_delay (1, false);

  thread_preempt_disable ();

  for (size_t i = 0; i < ARRAY_SIZE (test_waiters); i++)
    {
      int error = semaphore_post (&test_semaphore);
      error_check (error, "semaphore_post");
    }

  thread_preempt_enable ();

  for (size_t i = 0; i < ARRAY_SIZE (test_waiters); i++)
    thread_join (test_waiters[i]);

  log_info ("test (semaphore): OK");
}

TEST_INLINE (semaphore)
{
  semaphore_init (&test_semaphore, 0, TEST_NR_WAITERS);

  struct cpumap *cpumap;
  int error = cpumap_create (&cpumap);
  error_check (error, "cpumap_create");
  cpumap_zero (cpumap);
  cpumap_set (cpumap, 0);

  struct thread_attr attr;
  for (size_t i = 0; i < ARRAY_SIZE (test_waiters); i++)
    {
      char name[THREAD_NAME_SIZE];
      snprintf (name, sizeof (name), THREAD_KERNEL_PREFIX "test_semwait:%zu", i);
      thread_attr_init (&attr, name);
      thread_attr_set_cpumap (&attr, cpumap);
      error = thread_create (&test_waiters[i], &attr, test_wait, NULL);
      error_check (error, "thread_create");
    }

  thread_attr_init (&attr, THREAD_KERNEL_PREFIX "test_sempost");
  thread_attr_set_detached (&attr);
  thread_attr_set_cpumap (&attr, cpumap);
  error = thread_create (NULL, &attr, test_post, NULL);
  error_check (error, "thread_create");

  return (TEST_RUNNING);
}