mysys_my_atomic-t.cc

/* Copyright (c) 2006, 2012, Oracle and/or its affiliates. All rights reserved.

   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; version 2 of the License.

   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, write to the Free Software
   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA */

// First include (the generated) my_config.h, to get correct platform defines.
#include "my_config.h"
#include <gtest/gtest.h>

#include <my_global.h>
#include <my_sys.h>
#include <my_atomic.h>


namespace mysys_my_atomic_unittest {

#include "thr_template.cc"

volatile int32 b32;
volatile int32  c32;
my_atomic_rwlock_t rwl;

/* add and sub a random number in a loop. Must get 0 at the end */
pthread_handler_t test_atomic_add(void *arg)
{
  int m= (*(int *)arg)/2;
  int32 x;
  for (x= ((int)(intptr)(&m)); m ; m--)
  {
    x= (x*m+0x87654321) & INT_MAX32;
    my_atomic_rwlock_wrlock(&rwl);
    my_atomic_add32(&bad, x);
    my_atomic_rwlock_wrunlock(&rwl);

    my_atomic_rwlock_wrlock(&rwl);
    my_atomic_add32(&bad, -x);
    my_atomic_rwlock_wrunlock(&rwl);
  }
  mysql_mutex_lock(&mutex);
  if (!--running_threads) mysql_cond_signal(&cond);
  mysql_mutex_unlock(&mutex);
  return 0;
}

volatile int64 a64;
/* add and sub a random number in a loop. Must get 0 at the end */
pthread_handler_t test_atomic_add64(void *arg)
{
  int m= (*(int *)arg)/2;
  int64 x;
  for (x= ((int64)(intptr)(&m)); m ; m--)
  {
    x= (x*m+0xfdecba987654321LL) & INT_MAX64;
    my_atomic_rwlock_wrlock(&rwl);
    my_atomic_add64(&a64, x);
    my_atomic_rwlock_wrunlock(&rwl);

    my_atomic_rwlock_wrlock(&rwl);
    my_atomic_add64(&a64, -x);
    my_atomic_rwlock_wrunlock(&rwl);
  }
  mysql_mutex_lock(&mutex);
  if (!--running_threads)
  {
    bad= (a64 != 0);
    mysql_cond_signal(&cond);
  }
  mysql_mutex_unlock(&mutex);
  return 0;
}


/*
  1. generate thread number 0..N-1 from b32
  2. add it to bad
  3. swap thread numbers in c32
  4. (optionally) one more swap to avoid 0 as a result
  5. subtract result from bad
  must get 0 in bad at the end
*/
pthread_handler_t test_atomic_fas(void *arg)
{
  int    m= *(int *)arg;
  int32  x;

  my_atomic_rwlock_wrlock(&rwl);
  x= my_atomic_add32(&b32, 1);
  my_atomic_rwlock_wrunlock(&rwl);

  my_atomic_rwlock_wrlock(&rwl);
  my_atomic_add32(&bad, x);
  my_atomic_rwlock_wrunlock(&rwl);

  for (; m ; m--)
  {
    my_atomic_rwlock_wrlock(&rwl);
    x= my_atomic_fas32(&c32, x);
    my_atomic_rwlock_wrunlock(&rwl);
  }

  if (!x)
  {
    my_atomic_rwlock_wrlock(&rwl);
    x= my_atomic_fas32(&c32, x);
    my_atomic_rwlock_wrunlock(&rwl);
  }

  my_atomic_rwlock_wrlock(&rwl);
  my_atomic_add32(&bad, -x);
  my_atomic_rwlock_wrunlock(&rwl);

  mysql_mutex_lock(&mutex);
  if (!--running_threads) mysql_cond_signal(&cond);
  mysql_mutex_unlock(&mutex);
  return 0;
}

/*
  same as test_atomic_add, but my_atomic_add32 is emulated with
  my_atomic_cas32 - notice that the slowdown is proportional to the
  number of CPUs
*/
pthread_handler_t test_atomic_cas(void *arg)
{
  int m= (*(int *)arg)/2, ok= 0;
  int32 x, y;
  for (x= ((int)(intptr)(&m)); m ; m--)
  {
    my_atomic_rwlock_wrlock(&rwl);
    y= my_atomic_load32(&bad);
    my_atomic_rwlock_wrunlock(&rwl);
    x= (x*m+0x87654321) & INT_MAX32;
    do {
      my_atomic_rwlock_wrlock(&rwl);
      ok= my_atomic_cas32(&bad, &y, (uint32)y+x);
      my_atomic_rwlock_wrunlock(&rwl);
    } while (!ok) ;
    do {
      my_atomic_rwlock_wrlock(&rwl);
      ok= my_atomic_cas32(&bad, &y, y-x);
      my_atomic_rwlock_wrunlock(&rwl);
    } while (!ok) ;
  }
  mysql_mutex_lock(&mutex);
  if (!--running_threads) mysql_cond_signal(&cond);
  mysql_mutex_unlock(&mutex);
  return 0;
}


void do_tests()
{
  bad= my_atomic_initialize();
  EXPECT_FALSE(bad) << "my_atomic_initialize() returned";

  my_atomic_rwlock_init(&rwl);

  b32= c32= 0;
  test_concurrently("my_atomic_add32", test_atomic_add, THREADS, CYCLES);
  b32= c32= 0;
  test_concurrently("my_atomic_fas32", test_atomic_fas, THREADS, CYCLES);
  b32= c32= 0;
  test_concurrently("my_atomic_cas32", test_atomic_cas, THREADS, CYCLES);

  {
    /*
      If b is not volatile, the wrong assembly code is generated on OSX Lion
      as the variable is optimized away as a constant.
      See Bug#62533 / Bug#13030056.
      Another workaround is to specify architecture explicitly using e.g.
      CFLAGS/CXXFLAGS= "-m64".
    */
    volatile int64 b=0x1000200030004000LL;
    a64=0;
    my_atomic_add64(&a64, b);
    EXPECT_EQ(a64, b) << "add64";
  }
  a64=0;
  test_concurrently("my_atomic_add64", test_atomic_add64, THREADS, CYCLES);

  my_atomic_rwlock_destroy(&rwl);
}


TEST(Mysys, Atomic)
{
  mysql_mutex_init(0, &mutex, 0);
  mysql_cond_init(0, &cond, NULL);
  pthread_attr_init(&thr_attr);
  pthread_attr_setdetachstate(&thr_attr, PTHREAD_CREATE_DETACHED);
 
  do_tests();

  mysql_mutex_destroy(&mutex);
  mysql_cond_destroy(&cond);
  pthread_attr_destroy(&thr_attr);
}

}