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// $Id$
// ============================================================================
//
// = LIBRARY
// tests
//
// = FILENAME
// Reader_Writer_Test.cpp
//
// = DESCRIPTION
// This test program verifies the functionality of the ACE_OS
// implementation of readers/writer locks on Win32 and Posix
// pthreads.
//
// = AUTHOR
// Prashant Jain and Doug C. Schmidt
//
// ============================================================================
#include "test_config.h"
#include "ace/Synch.h"
#include "ace/Thread.h"
#include "ace/Thread_Manager.h"
#include "ace/Get_Opt.h"
#if defined (ACE_HAS_THREADS)
// Default number of iterations.
static size_t n_iterations = 100;
// Default number of loops.
static size_t n_loops = 100;
// Default number of readers.
static size_t n_readers = 6;
// Default number of writers.
static size_t n_writers = 4;
// Thread id of last writer.
static ACE_thread_t shared_data;
// Lock for shared_data.
static ACE_RW_Mutex rw_mutex;
// Count of the number of readers and writers.
static ACE_Atomic_Op<ACE_Thread_Mutex, int> current_readers;
static ACE_Atomic_Op<ACE_Thread_Mutex, int> current_writers;
// Explain usage and exit.
static void
print_usage_and_die (void)
{
ACE_DEBUG ((LM_DEBUG,
ASYS_TEXT ("usage: %n [-r n_readers] [-w n_writers] [-n iteration_count]\n")));
ACE_OS::exit (1);
}
static void
parse_args (int argc, ASYS_TCHAR *argv[])
{
ACE_Get_Opt get_opt (argc, argv, ASYS_TEXT ("r:w:n:"));
int c;
while ((c = get_opt ()) != -1)
switch (c)
{
case 'r':
n_readers = ACE_OS::atoi (get_opt.optarg);
break;
case 'w':
n_writers = ACE_OS::atoi (get_opt.optarg);
break;
case 'n':
n_iterations = ACE_OS::atoi (get_opt.optarg);
break;
default:
print_usage_and_die ();
break;
}
}
// Iterate <n_iterations> each time checking that nobody modifies the data
// while we have a read lock.
static void *
reader (void *)
{
ACE_DEBUG ((LM_DEBUG, ASYS_TEXT (" (%t) reader starting\n")));
// We use a random pause, around 2msec with 1msec jittering.
int usecs = 1000 + ACE_OS::rand() % 2000;
ACE_Time_Value pause(0, usecs);
for (size_t iterations = 1; iterations <= n_iterations; iterations++)
{
ACE_OS::sleep(pause);
ACE_Read_Guard<ACE_RW_Mutex> g (rw_mutex);
// int n = ++current_readers;
// ACE_DEBUG ((LM_DEBUG, ASYS_TEXT (" (%t) I'm reader number %d\n"), n));
if (current_writers > 0)
ACE_DEBUG ((LM_DEBUG, ASYS_TEXT (" (%t) writers found!!!\n")));
ACE_thread_t data = shared_data;
for (size_t loop = 1; loop <= n_loops; loop++)
{
ACE_Thread::yield ();
if (!ACE_OS::thr_equal (shared_data, data))
ACE_DEBUG ((LM_DEBUG,
ASYS_TEXT (" (%t) somebody changed %d to %d\n"),
data, shared_data));
}
--current_readers;
//ACE_DEBUG ((LM_DEBUG, ASYS_TEXT (" (%t) done with reading guarded data\n")));
ACE_DEBUG((LM_DEBUG, ASYS_TEXT (" (%t) read %d done at %T\n"), iterations));
// ACE_Thread::yield ();
}
return 0;
}
// Iterate <n_iterations> each time modifying the global data
// and checking that nobody steps on it while we can write it.
static void *
writer (void *)
{
ACE_DEBUG ((LM_DEBUG, ASYS_TEXT (" (%t) writer starting\n")));
// We use a random pause, around 2msec with 1msec jittering.
int usecs = 1000 + ACE_OS::rand() % 2000;
ACE_Time_Value pause(0, usecs);
for (size_t iterations = 1; iterations <= n_iterations; iterations++)
{
ACE_OS::sleep(pause);
ACE_Write_Guard<ACE_RW_Mutex> g (rw_mutex);
++current_writers;
//ACE_DEBUG ((LM_DEBUG, ASYS_TEXT (" (%t) writing to guarded data\n")));
if (current_writers > 1)
ACE_DEBUG ((LM_DEBUG, ASYS_TEXT (" (%t) other writers found!!!\n")));
if (current_readers > 0)
ACE_DEBUG ((LM_DEBUG, ASYS_TEXT (" (%t) readers found!!!\n")));
ACE_thread_t self = ACE_Thread::self ();
shared_data = self;
for (size_t loop = 1; loop <= n_loops; loop++)
{
ACE_Thread::yield ();
if (!ACE_OS::thr_equal (shared_data, self))
ACE_DEBUG ((LM_DEBUG,
ASYS_TEXT (" (%t) somebody wrote on my data %d\n"),
shared_data));
}
--current_writers;
//ACE_DEBUG ((LM_DEBUG, ASYS_TEXT (" (%t) done with guarded data\n")));
ACE_DEBUG((LM_DEBUG, ASYS_TEXT (" (%t) write %d done at %T\n"), iterations));
// ACE_Thread::yield ();
}
return 0;
}
#if defined (ACE_HAS_EXPLICIT_TEMPLATE_INSTANTIATION)
template class ACE_Atomic_Op<ACE_Thread_Mutex, int>;
template class ACE_Read_Guard<ACE_RW_Mutex>;
template class ACE_Write_Guard<ACE_RW_Mutex>;
template class ACE_Guard<ACE_RW_Mutex>;
#elif defined (ACE_HAS_TEMPLATE_INSTANTIATION_PRAGMA)
#pragma instantiate ACE_Atomic_Op<ACE_Thread_Mutex, int>
#pragma instantiate ACE_Read_Guard<ACE_RW_Mutex>
#pragma instantiate ACE_Write_Guard<ACE_RW_Mutex>
#pragma instantiate ACE_Guard<ACE_RW_Mutex>
#endif /* ACE_HAS_EXPLICIT_TEMPLATE_INSTANTIATION */
#endif /* ACE_HAS_THREADS */
// Spawn off threads.
int main (int argc, ASYS_TCHAR *argv[])
{
ACE_START_TEST (ASYS_TEXT ("Reader_Writer_Test"));
#if defined (ACE_HAS_THREADS)
parse_args (argc, argv);
current_readers = 0; // Possibly already done
current_writers = 0; // Possibly already done
ACE_DEBUG ((LM_DEBUG, ASYS_TEXT (" (%t) main thread starting\n")));
if (ACE_Thread_Manager::instance ()->spawn_n (n_readers,
ACE_THR_FUNC (reader),
0,
THR_NEW_LWP) == -1)
ACE_ERROR_RETURN ((LM_ERROR, ASYS_TEXT ("%p\n"), ASYS_TEXT ("spawn_n")), 1);
else if (ACE_Thread_Manager::instance ()->spawn_n (n_writers,
ACE_THR_FUNC (writer),
0,
THR_NEW_LWP) == -1)
ACE_ERROR_RETURN ((LM_ERROR, ASYS_TEXT ("%p\n"), ASYS_TEXT ("spawn_n")), 1);
ACE_Thread_Manager::instance ()->wait ();
ACE_DEBUG ((LM_DEBUG, ASYS_TEXT (" (%t) exiting main thread\n")));
#else
ACE_UNUSED_ARG (argc);
ACE_UNUSED_ARG (argv);
ACE_ERROR ((LM_ERROR, ASYS_TEXT ("threads not supported on this platform\n")));
#endif /* ACE_HAS_THREADS */
ACE_END_TEST;
return 0;
}
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