test-example-projects/c++_projects/280w-mysql-8.0.18/unittest/gunit/partitioned_rwlock-t.cc

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   GNU General Public License, version 2.0, for more details.

   You should have received a copy of the GNU General Public License
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   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA */

/* Simple unit tests for thread id partitioned rwlocks. */

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

#include <gtest/gtest.h>
#include <sys/types.h>

#include "sql/auth/partitioned_rwlock.h"
#include "unittest/gunit/thread_utils.h"

namespace partitioned_rwlock_unittest {

using thread::Thread;

TEST(PartitionedRwlock, InitDestroy) {
  Partitioned_rwlock rwlock;

  bool r = rwlock.init(32
#ifdef HAVE_PSI_INTERFACE
                       ,
                       PSI_NOT_INSTRUMENTED
#endif
  );
  EXPECT_FALSE(r);
  rwlock.destroy();

  r = rwlock.init(8
#ifdef HAVE_PSI_INTERFACE
                  ,
                  PSI_NOT_INSTRUMENTED
#endif
  );
  EXPECT_FALSE(r);
  rwlock.destroy();
}

class Reader_thread : public Thread {
 public:
  void init(uint thread_id, Partitioned_rwlock *rwlock,
            volatile uint *shared_counter) {
    m_thread_id = thread_id;
    m_rwlock = rwlock;
    m_shared_counter = shared_counter;
  }
  virtual void run() {
    for (uint i = 0; i < 1000; ++i) {
      Partitioned_rwlock_read_guard lock(m_rwlock, m_thread_id);
      /*
        With correct rwlock implementation readers should not
        observe counter values not divisible by 100.
      */
      EXPECT_EQ(0U, (*m_shared_counter % 100));
    }
  }

 private:
  uint m_thread_id;
  Partitioned_rwlock *m_rwlock;
  volatile uint *m_shared_counter;
};

class Writer_thread : public Thread {
 public:
  Writer_thread(Partitioned_rwlock *rwlock, volatile uint *shared_counter)
      : m_rwlock(rwlock), m_shared_counter(shared_counter) {}
  virtual void run() {
    for (uint i = 0; i < 1000; ++i) {
      Partitioned_rwlock_write_guard lock(m_rwlock);
      /*
        Add 100 to counter value using 100 single increments. We rely
        on counter being "volatile" to prevent compiler optimizations.
      */
      for (uint j = 0; j < 100; ++j) {
        ++*m_shared_counter;
      }
    }
  }

 private:
  Partitioned_rwlock *m_rwlock;
  volatile uint *m_shared_counter;
};

/**
  Concurrent test which easily breaks if rwlock implementation is wrong
  (e.g. if wrlock() operation doesn't lock all partitions).
*/

TEST(PartitionedRwlock, Concurrent) {
  const uint PARTS_NUM = 32;

  Partitioned_rwlock rwlock;
  volatile uint shared_counter = 0;
  rwlock.init(PARTS_NUM
#ifdef HAVE_PSI_INTERFACE
              ,
              PSI_NOT_INSTRUMENTED
#endif
  );

  Reader_thread readers[PARTS_NUM];
  Writer_thread writer(&rwlock, &shared_counter);
  for (uint i = 0; i < PARTS_NUM; ++i)
    readers[i].init(i, &rwlock, &shared_counter);

  writer.start();
  for (uint i = 0; i < PARTS_NUM; ++i) readers[i].start();

  for (uint i = 0; i < PARTS_NUM; ++i) readers[i].join();
  writer.join();

  rwlock.destroy();
}

}  // namespace partitioned_rwlock_unittest