Make refcounting threadsafe by using atomic operations. (#166020, Wim

2005-07-15  Matthias Clasen  <mclasen@redhat.com>

	Make refcounting threadsafe by using atomic
	operations.  (#166020, Wim Taymans)

	* gobject.c: Use a recursive lock to protect the
	notify queue.
	(g_object_unref): Get rid of g_object_last_unref and
	do the last unref handling in g_object_unref.
	(g_object_ref, g_object_unref): Use atomic operations.

	* gsignal.c (struct _HandlerMatch): Use a full integer
	for the ref_count field.
	(handler_ref, handler_unref_R): Use atomic operations.

	* gparam.c (g_param_spec_ref, g_param_spec_unref):
	Use atomic operations instead of a lock to make the
	refcounting threadsafe.

	* gclosure.c (g_closure_ref, g_closure_unref): Use atomic
	operations. This is more complicated here, since the
	refcount is stored in a bitfield, so we also have
	to access all other bitfield members atomically.

	* gsignal.c (handlers_find): Read the meta_marshal flag
	of the closure atomically.

	* tests/Makefile.am (SUBDIRS): Add tests/refcount

	* configure.in: Add tests/refcount

	* tests/refcount/properties.c: Test property changes
	from multiple threads.

	* tests/refcount/signals.c: Test signal emission from
	multiple threads.

	* tests/refcount/objects.c: Test refcounting from
	multiple threads.

	* tests/refcount/objects2.c:
	* tests/refcount/properties2.c: Tests to measure the
	overhead of threadsafe refcounting.

	* glib/giochannel.c (g_io_channel_ref, g_io_channel_unref):
	Use atomic operations to make refcounting
	threadsafe.  (#166020, Wim Taymans)

tests/refcount/Makefile.am

@@ -0,0 +1,34 @@
+INCLUDES =					\
+	-I$(top_srcdir)				\
+	-I$(top_srcdir)/glib			\
+	-I$(top_srcdir)/gmodule			\
+	$(GLIB_DEBUG_FLAGS)
+
+libglib = $(top_builddir)/glib/libglib-2.0.la
+libgthread = $(top_builddir)/gthread/libgthread-2.0.la
+libgmodule = $(top_builddir)/gmodule/libgmodule-2.0.la
+libgobject = $(top_builddir)/gobject/libgobject-2.0.la
+
+LDADD = $(libgobject) $(libgthread)
+
+test_programs =					\
+	signal1					\
+	signal2					\
+	signal3					\
+	objects					\
+	objects2				\
+	properties				\
+	properties2
+
+signal1_SOURCES = signals.c
+signal1_CFLAGS = -DTESTNUM=1 $(AM_CFLAGS)
+signal2_SOURCES = signals.c
+signal2_CFLAGS = -DTESTNUM=2 $(AM_CFLAGS)
+signal3_SOURCES = signals.c
+signal3_CFLAGS = -DTESTNUM=3 $(AM_CFLAGS)
+
+check_PROGRAMS = $(test_programs)
+
+TESTS = $(test_programs)
+TESTS_ENVIRONMENT = srcdir=$(srcdir) \
+	LIBCHARSET_ALIAS_DIR=$(top_builddir)/glib/libcharset

tests/refcount/objects.c

@@ -0,0 +1,155 @@
+#include <unistd.h>
+#include <glib.h>
+#include <glib-object.h>
+
+#define G_TYPE_TEST               (g_test_get_type ())
+#define G_TEST(test)              (G_TYPE_CHECK_INSTANCE_CAST ((test), G_TYPE_TEST, GTest))
+#define G_IS_TEST(test)           (G_TYPE_CHECK_INSTANCE_TYPE ((test), G_TYPE_TEST))
+#define G_TEST_CLASS(tclass)      (G_TYPE_CHECK_CLASS_CAST ((tclass), G_TYPE_TEST, GTestClass))
+#define G_IS_TEST_CLASS(tclass)   (G_TYPE_CHECK_CLASS_TYPE ((tclass), G_TYPE_TEST))
+#define G_TEST_GET_CLASS(test)    (G_TYPE_INSTANCE_GET_CLASS ((test), G_TYPE_TEST, GTestClass))
+
+typedef struct _GTest GTest;
+typedef struct _GTestClass GTestClass;
+
+struct _GTest
+{
+  GObject object;
+};
+
+struct _GTestClass
+{
+  GObjectClass parent_class;
+};
+
+static GType g_test_get_type (void);
+static gboolean stopping;
+
+static void g_test_class_init (GTestClass * klass);
+static void g_test_init (GTest * test);
+static void g_test_dispose (GObject * object);
+
+static GObjectClass *parent_class = NULL;
+
+static GType
+g_test_get_type (void)
+{
+  static GType test_type = 0;
+
+  if (!test_type) {
+    static const GTypeInfo test_info = {
+      sizeof (GTestClass),
+      NULL,
+      NULL,
+      (GClassInitFunc) g_test_class_init,
+      NULL,
+      NULL,
+      sizeof (GTest),
+      0,
+      (GInstanceInitFunc) g_test_init,
+      NULL
+    };
+
+    test_type = g_type_register_static (G_TYPE_OBJECT, "GTest",
+        &test_info, 0);
+  }
+  return test_type;
+}
+
+static void
+g_test_class_init (GTestClass * klass)
+{
+  GObjectClass *gobject_class;
+
+  gobject_class = (GObjectClass *) klass;
+
+  parent_class = g_type_class_ref (G_TYPE_OBJECT);
+
+  gobject_class->dispose = g_test_dispose;
+}
+
+static void
+g_test_init (GTest * test)
+{
+  g_print ("init %p\n", test);
+}
+
+static void
+g_test_dispose (GObject * object)
+{
+  GTest *test;
+
+  test = G_TEST (object);
+
+  g_print ("dispose %p!\n", object);
+
+  G_OBJECT_CLASS (parent_class)->dispose (object);
+}
+
+static void
+g_test_do_refcount (GTest * test)
+{
+  g_object_ref (test); 
+  g_object_unref (test); 
+}
+
+static gpointer
+run_thread (GTest * test)
+{
+  gint i = 0;
+
+  while (!stopping) {
+    g_test_do_refcount (test);
+    if ((i++ % 100000) == 0) {
+      g_print (".");
+      g_usleep (1);             /* context switch */
+    }
+  }
+
+  return NULL;
+}
+
+int
+main (int argc, char **argv)
+{
+  gint i;
+  GTest *test1, *test2;
+  GArray *test_threads;
+
+  g_thread_init (NULL);
+  g_type_init ();
+
+  test1 = g_object_new (G_TYPE_TEST, NULL);
+  test2 = g_object_new (G_TYPE_TEST, NULL);
+
+  test_threads = g_array_new (FALSE, FALSE, sizeof (GThread *));
+
+  stopping = FALSE;
+
+  for (i = 0; i < 20; i++) {
+    GThread *thread;
+
+    thread = g_thread_create ((GThreadFunc) run_thread, test1, TRUE, NULL);
+    g_array_append_val (test_threads, thread);
+
+    thread = g_thread_create ((GThreadFunc) run_thread, test2, TRUE, NULL);
+    g_array_append_val (test_threads, thread);
+  }
+  sleep (5);
+
+  stopping = TRUE;
+
+  g_print ("\nstopping\n");
+
+  /* join all threads */
+  for (i = 0; i < 40; i++) {
+    GThread *thread;
+
+    thread = g_array_index (test_threads, GThread *, i);
+    g_thread_join (thread);
+  }
+
+  g_print ("stopped\n");
+
+  return 0;
+}

tests/refcount/objects2.c

@@ -0,0 +1,111 @@
+#include <unistd.h>
+#include <glib.h>
+#include <glib-object.h>
+
+#define G_TYPE_TEST               (g_test_get_type ())
+#define G_TEST(test)              (G_TYPE_CHECK_INSTANCE_CAST ((test), G_TYPE_TEST, GTest))
+#define G_IS_TEST(test)           (G_TYPE_CHECK_INSTANCE_TYPE ((test), G_TYPE_TEST))
+#define G_TEST_CLASS(tclass)      (G_TYPE_CHECK_CLASS_CAST ((tclass), G_TYPE_TEST, GTestClass))
+#define G_IS_TEST_CLASS(tclass)   (G_TYPE_CHECK_CLASS_TYPE ((tclass), G_TYPE_TEST))
+#define G_TEST_GET_CLASS(test)    (G_TYPE_INSTANCE_GET_CLASS ((test), G_TYPE_TEST, GTestClass))
+
+typedef struct _GTest GTest;
+typedef struct _GTestClass GTestClass;
+
+struct _GTest
+{
+  GObject object;
+};
+
+struct _GTestClass
+{
+  GObjectClass parent_class;
+};
+
+static GType g_test_get_type (void);
+
+static void g_test_class_init (GTestClass * klass);
+static void g_test_init (GTest * test);
+static void g_test_dispose (GObject * object);
+
+static GObjectClass *parent_class = NULL;
+
+static GType
+g_test_get_type (void)
+{
+  static GType test_type = 0;
+
+  if (!test_type) {
+    static const GTypeInfo test_info = {
+      sizeof (GTestClass),
+      NULL,
+      NULL,
+      (GClassInitFunc) g_test_class_init,
+      NULL,
+      NULL,
+      sizeof (GTest),
+      0,
+      (GInstanceInitFunc) g_test_init,
+      NULL
+    };
+
+    test_type = g_type_register_static (G_TYPE_OBJECT, "GTest",
+        &test_info, 0);
+  }
+  return test_type;
+}
+
+static void
+g_test_class_init (GTestClass * klass)
+{
+  GObjectClass *gobject_class;
+
+  gobject_class = (GObjectClass *) klass;
+
+  parent_class = g_type_class_ref (G_TYPE_OBJECT);
+
+  gobject_class->dispose = g_test_dispose;
+}
+
+static void
+g_test_init (GTest * test)
+{
+  g_print ("init %p\n", test);
+}
+
+static void
+g_test_dispose (GObject * object)
+{
+  GTest *test;
+
+  test = G_TEST (object);
+
+  g_print ("dispose %p!\n", object);
+
+  G_OBJECT_CLASS (parent_class)->dispose (object);
+}
+
+static void
+g_test_do_refcount (GTest * test)
+{
+  g_object_ref (test); 
+  g_object_unref (test); 
+}
+
+int
+main (int argc, char **argv)
+{
+  gint i;
+  GTest *test;
+
+  g_thread_init (NULL);
+  g_type_init ();
+
+  test = g_object_new (G_TYPE_TEST, NULL);
+
+  for (i=0; i<100000000; i++) {
+    g_test_do_refcount (test);
+  }
+
+  return 0;
+}

tests/refcount/properties.c

@@ -0,0 +1,254 @@
+#include <unistd.h>
+#include <glib.h>
+#include <glib-object.h>
+
+#define G_TYPE_TEST               (g_test_get_type ())
+#define G_TEST(test)              (G_TYPE_CHECK_INSTANCE_CAST ((test), G_TYPE_TEST, GTest))
+#define G_IS_TEST(test)           (G_TYPE_CHECK_INSTANCE_TYPE ((test), G_TYPE_TEST))
+#define G_TEST_CLASS(tclass)      (G_TYPE_CHECK_CLASS_CAST ((tclass), G_TYPE_TEST, GTestClass))
+#define G_IS_TEST_CLASS(tclass)   (G_TYPE_CHECK_CLASS_TYPE ((tclass), G_TYPE_TEST))
+#define G_TEST_GET_CLASS(test)    (G_TYPE_INSTANCE_GET_CLASS ((test), G_TYPE_TEST, GTestClass))
+
+enum {
+  PROP_0,
+  PROP_DUMMY
+};
+
+typedef struct _GTest GTest;
+typedef struct _GTestClass GTestClass;
+
+struct _GTest
+{
+  GObject object;
+
+  gint dummy;
+
+  gint count;
+};
+
+struct _GTestClass
+{
+  GObjectClass parent_class;
+};
+
+static GType g_test_get_type (void);
+static gboolean stopping;
+
+static void g_test_class_init (GTestClass * klass);
+static void g_test_init (GTest * test);
+static void g_test_dispose (GObject * object);
+static void g_test_get_property (GObject    *object,
+				 guint       prop_id,
+				 GValue     *value,
+				 GParamSpec *pspec);
+static void g_test_set_property (GObject      *object,
+				 guint         prop_id,
+				 const GValue *value,
+				 GParamSpec   *pspec);
+
+static GObjectClass *parent_class = NULL;
+
+static GType
+g_test_get_type (void)
+{
+  static GType test_type = 0;
+
+  if (!test_type) {
+    static const GTypeInfo test_info = {
+      sizeof (GTestClass),
+      NULL,
+      NULL,
+      (GClassInitFunc) g_test_class_init,
+      NULL,
+      NULL,
+      sizeof (GTest),
+      0,
+      (GInstanceInitFunc) g_test_init,
+      NULL
+    };
+
+    test_type = g_type_register_static (G_TYPE_OBJECT, "GTest",
+        &test_info, 0);
+  }
+  return test_type;
+}
+
+static void
+g_test_class_init (GTestClass * klass)
+{
+  GObjectClass *gobject_class;
+
+  gobject_class = (GObjectClass *) klass;
+
+  parent_class = g_type_class_ref (G_TYPE_OBJECT);
+
+  gobject_class->dispose = g_test_dispose;
+  gobject_class->get_property = g_test_get_property;
+  gobject_class->set_property = g_test_set_property;
+
+  g_object_class_install_property (gobject_class,
+				   PROP_DUMMY,
+				   g_param_spec_int ("dummy",
+						     NULL, 
+						     NULL,
+						     0, G_MAXINT, 0,
+						     G_PARAM_READWRITE));
+}
+
+static void
+g_test_init (GTest * test)
+{
+  g_print ("init %p\n", test);
+}
+
+static void
+g_test_dispose (GObject * object)
+{
+  GTest *test;
+
+  test = G_TEST (object);
+
+  g_print ("dispose %p!\n", object);
+
+  G_OBJECT_CLASS (parent_class)->dispose (object);
+}
+
+static void 
+g_test_get_property (GObject    *object,
+		     guint       prop_id,
+		     GValue     *value,
+		     GParamSpec *pspec)
+{
+  GTest *test;
+
+  test = G_TEST (object);
+
+  switch (prop_id)
+    {
+    case PROP_DUMMY:
+      g_value_set_int (value, test->dummy);
+      break;
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+    }
+}
+
+static void 
+g_test_set_property (GObject      *object,
+		     guint         prop_id,
+		     const GValue *value,
+		     GParamSpec   *pspec)
+{
+  GTest *test;
+
+  test = G_TEST (object);
+
+  switch (prop_id)
+    {
+    case PROP_DUMMY:
+      test->dummy = g_value_get_int (value);
+      break;
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+    }
+}
+
+static void
+dummy_notify (GObject    *object,
+              GParamSpec *pspec)
+{
+  GTest *test;
+
+  test = G_TEST (object);
+
+  test->count++;  
+}
+
+static void
+g_test_do_property (GTest * test)
+{
+  gint dummy;
+
+  g_object_get (test, "dummy", &dummy, NULL);
+  g_object_set (test, "dummy", dummy + 1, NULL);
+}
+
+static gpointer
+run_thread (GTest * test)
+{
+  gint i = 0;
+
+  while (!stopping) {
+    g_test_do_property (test);
+    if ((i++ % 100000) == 0) {
+      g_print (".");
+      g_usleep (1);             /* context switch */
+    }
+  }
+
+  return NULL;
+}
+
+int
+main (int argc, char **argv)
+{
+  gint i;
+  GArray *test_objects;
+  GArray *test_threads;
+
+  g_thread_init (NULL);
+  g_type_init ();
+
+  test_objects = g_array_new (FALSE, FALSE, sizeof (GTest *));
+
+  for (i = 0; i < 20; i++) {
+    GTest *test;
+    
+    test = g_object_new (G_TYPE_TEST, NULL);
+    g_array_append_val (test_objects, test);
+
+    g_assert (test->count == test->dummy);
+    g_signal_connect (test, "notify::dummy", G_CALLBACK (dummy_notify), NULL);
+  }
+    
+  test_threads = g_array_new (FALSE, FALSE, sizeof (GThread *));
+
+  stopping = FALSE;
+
+  for (i = 0; i < 20; i++) {
+    GThread *thread;
+    GTest *test;
+
+    test = g_array_index (test_objects, GTest *, i);
+
+    thread = g_thread_create ((GThreadFunc) run_thread, test, TRUE, NULL);
+    g_array_append_val (test_threads, thread);
+  }
+  sleep (5);
+
+  stopping = TRUE;
+
+  g_print ("\nstopping\n");
+
+  /* join all threads */
+  for (i = 0; i < 20; i++) {
+    GThread *thread;
+
+    thread = g_array_index (test_threads, GThread *, i);
+    g_thread_join (thread);
+  }
+
+  g_print ("stopped\n");
+
+  for (i = 0; i < 20; i++) {
+    GTest *test;
+
+    test = g_array_index (test_objects, GTest *, i);
+
+    g_assert (test->count == test->dummy);
+  }
+
+  return 0;
+}

tests/refcount/properties2.c

@@ -0,0 +1,195 @@
+#include <unistd.h>
+#include <glib.h>
+#include <glib-object.h>
+
+#define G_TYPE_TEST               (g_test_get_type ())
+#define G_TEST(test)              (G_TYPE_CHECK_INSTANCE_CAST ((test), G_TYPE_TEST, GTest))
+#define G_IS_TEST(test)           (G_TYPE_CHECK_INSTANCE_TYPE ((test), G_TYPE_TEST))
+#define G_TEST_CLASS(tclass)      (G_TYPE_CHECK_CLASS_CAST ((tclass), G_TYPE_TEST, GTestClass))
+#define G_IS_TEST_CLASS(tclass)   (G_TYPE_CHECK_CLASS_TYPE ((tclass), G_TYPE_TEST))
+#define G_TEST_GET_CLASS(test)    (G_TYPE_INSTANCE_GET_CLASS ((test), G_TYPE_TEST, GTestClass))
+
+enum {
+  PROP_0,
+  PROP_DUMMY
+};
+
+typedef struct _GTest GTest;
+typedef struct _GTestClass GTestClass;
+
+struct _GTest
+{
+  GObject object;
+
+  gint dummy;
+};
+
+struct _GTestClass
+{
+  GObjectClass parent_class;
+};
+
+static GType g_test_get_type (void);
+
+static void g_test_class_init (GTestClass * klass);
+static void g_test_init (GTest * test);
+static void g_test_dispose (GObject * object);
+static void g_test_get_property (GObject    *object,
+				 guint       prop_id,
+				 GValue     *value,
+				 GParamSpec *pspec);
+static void g_test_set_property (GObject      *object,
+				 guint         prop_id,
+				 const GValue *value,
+				 GParamSpec   *pspec);
+
+static GObjectClass *parent_class = NULL;
+
+static GType
+g_test_get_type (void)
+{
+  static GType test_type = 0;
+
+  if (!test_type) {
+    static const GTypeInfo test_info = {
+      sizeof (GTestClass),
+      NULL,
+      NULL,
+      (GClassInitFunc) g_test_class_init,
+      NULL,
+      NULL,
+      sizeof (GTest),
+      0,
+      (GInstanceInitFunc) g_test_init,
+      NULL
+    };
+
+    test_type = g_type_register_static (G_TYPE_OBJECT, "GTest",
+        &test_info, 0);
+  }
+  return test_type;
+}
+
+static void
+g_test_class_init (GTestClass * klass)
+{
+  GObjectClass *gobject_class;
+
+  gobject_class = (GObjectClass *) klass;
+
+  parent_class = g_type_class_ref (G_TYPE_OBJECT);
+
+  gobject_class->dispose = g_test_dispose;
+  gobject_class->get_property = g_test_get_property;
+  gobject_class->set_property = g_test_set_property;
+
+  g_object_class_install_property (gobject_class,
+				   PROP_DUMMY,
+				   g_param_spec_int ("dummy",
+						     NULL, 
+						     NULL,
+						     0, G_MAXINT, 0,
+						     G_PARAM_READWRITE));
+}
+
+static void
+g_test_init (GTest * test)
+{
+  g_print ("init %p\n", test);
+}
+
+static void
+g_test_dispose (GObject * object)
+{
+  GTest *test;
+
+  test = G_TEST (object);
+
+  g_print ("dispose %p!\n", object);
+
+  G_OBJECT_CLASS (parent_class)->dispose (object);
+}
+
+static void 
+g_test_get_property (GObject    *object,
+		     guint       prop_id,
+		     GValue     *value,
+		     GParamSpec *pspec)
+{
+  GTest *test;
+
+  test = G_TEST (object);
+
+  switch (prop_id)
+    {
+    case PROP_DUMMY:
+      g_value_set_int (value, test->dummy);
+      break;
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+    }
+}
+
+static void 
+g_test_set_property (GObject      *object,
+		     guint         prop_id,
+		     const GValue *value,
+		     GParamSpec   *pspec)
+{
+  GTest *test;
+
+  test = G_TEST (object);
+
+  switch (prop_id)
+    {
+    case PROP_DUMMY:
+      test->dummy = g_value_get_int (value);
+      break;
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+    }
+}
+
+static gint count = 0;
+
+static void
+dummy_notify (GObject    *object,
+              GParamSpec *pspec)
+{
+  count++;  
+}
+
+static void
+g_test_do_property (GTest * test)
+{
+  gint dummy;
+
+  g_object_get (test, "dummy", &dummy, NULL);
+  g_object_set (test, "dummy", dummy + 1, NULL);
+}
+
+int
+main (int argc, char **argv)
+{
+  gint i;
+  GTest *test;
+
+  g_thread_init (NULL);
+  g_type_init ();
+
+  test = g_object_new (G_TYPE_TEST, NULL);
+
+  g_signal_connect (test, "notify::dummy", G_CALLBACK (dummy_notify), NULL);
+
+  g_assert (count == test->dummy);
+
+  for (i=0; i<1000000; i++) {
+    g_test_do_property (test);
+  }
+
+  g_assert (count == test->dummy);
+
+  return 0;
+}

tests/refcount/signals.c

@@ -0,0 +1,281 @@
+#include <unistd.h>
+#include <glib.h>
+#include <glib-object.h>
+
+#define G_TYPE_TEST               (g_test_get_type ())
+#define G_TEST(test)              (G_TYPE_CHECK_INSTANCE_CAST ((test), G_TYPE_TEST, GTest))
+#define G_IS_TEST(test)           (G_TYPE_CHECK_INSTANCE_TYPE ((test), G_TYPE_TEST))
+#define G_TEST_CLASS(tclass)      (G_TYPE_CHECK_CLASS_CAST ((tclass), G_TYPE_TEST, GTestClass))
+#define G_IS_TEST_CLASS(tclass)   (G_TYPE_CHECK_CLASS_TYPE ((tclass), G_TYPE_TEST))
+#define G_TEST_GET_CLASS(test)    (G_TYPE_INSTANCE_GET_CLASS ((test), G_TYPE_TEST, GTestClass))
+
+static GRand *rand;
+
+typedef struct _GTest GTest;
+typedef struct _GTestClass GTestClass;
+
+struct _GTest
+{
+  GObject object;
+
+  gint value;
+};
+
+struct _GTestClass
+{
+  GObjectClass parent_class;
+
+  void (*test_signal1) (GTest * test, gint an_int);
+  void (*test_signal2) (GTest * test, gint an_int);
+};
+
+static GType g_test_get_type (void);
+static gboolean stopping;
+
+/* Element signals and args */
+enum
+{
+  TEST_SIGNAL1,
+  TEST_SIGNAL2,
+  /* add more above */
+  LAST_SIGNAL
+};
+
+enum
+{
+  ARG_0,
+  ARG_TEST_PROP
+};
+
+static void g_test_class_init (GTestClass * klass);
+static void g_test_init (GTest * test);
+static void g_test_dispose (GObject * object);
+
+static void signal2_handler (GTest * test, gint anint);
+
+static void g_test_set_property (GObject * object, guint prop_id,
+    const GValue * value, GParamSpec * pspec);
+static void g_test_get_property (GObject * object, guint prop_id,
+    GValue * value, GParamSpec * pspec);
+
+static GObjectClass *parent_class = NULL;
+
+static guint g_test_signals[LAST_SIGNAL] = { 0 };
+
+static GType
+g_test_get_type (void)
+{
+  static GType test_type = 0;
+
+  if (!test_type) {
+    static const GTypeInfo test_info = {
+      sizeof (GTestClass),
+      NULL,
+      NULL,
+      (GClassInitFunc) g_test_class_init,
+      NULL,
+      NULL,
+      sizeof (GTest),
+      0,
+      (GInstanceInitFunc) g_test_init,
+      NULL
+    };
+
+    rand = g_rand_new();
+
+    test_type = g_type_register_static (G_TYPE_OBJECT, "GTest",
+        &test_info, 0);
+  }
+  return test_type;
+}
+
+static void
+g_test_class_init (GTestClass * klass)
+{
+  GObjectClass *gobject_class;
+
+  gobject_class = (GObjectClass *) klass;
+
+  parent_class = g_type_class_ref (G_TYPE_OBJECT);
+
+  if (!g_thread_supported ())
+    g_thread_init (NULL);
+
+  gobject_class->dispose = g_test_dispose;
+  gobject_class->set_property = g_test_set_property;
+  gobject_class->get_property = g_test_get_property;
+
+  g_test_signals[TEST_SIGNAL1] =
+      g_signal_new ("test-signal1", G_TYPE_FROM_CLASS (klass),
+      G_SIGNAL_RUN_LAST, G_STRUCT_OFFSET (GTestClass, test_signal1), NULL,
+      NULL, g_cclosure_marshal_VOID__INT, G_TYPE_NONE, 1, G_TYPE_INT);
+  g_test_signals[TEST_SIGNAL2] =
+      g_signal_new ("test-signal2", G_TYPE_FROM_CLASS (klass),
+      G_SIGNAL_RUN_LAST, G_STRUCT_OFFSET (GTestClass, test_signal2), NULL,
+      NULL, g_cclosure_marshal_VOID__INT, G_TYPE_NONE, 1, G_TYPE_INT);
+
+  g_object_class_install_property (G_OBJECT_CLASS (klass), ARG_TEST_PROP,
+      g_param_spec_int ("test-prop", "Test Prop", "Test property",
+          0, 1, 0, G_PARAM_READWRITE));
+
+  klass->test_signal2 = signal2_handler;
+}
+
+static void
+g_test_init (GTest * test)
+{
+  g_print ("init %p\n", test);
+
+  test->value = 0;
+}
+
+static void
+g_test_dispose (GObject * object)
+{
+  GTest *test;
+
+  test = G_TEST (object);
+
+  g_print ("dispose %p!\n", object);
+
+  G_OBJECT_CLASS (parent_class)->dispose (object);
+}
+
+static void
+g_test_set_property (GObject * object, guint prop_id,
+    const GValue * value, GParamSpec * pspec)
+{
+  GTest *test;
+
+  test = G_TEST (object);
+
+  switch (prop_id) {
+    case ARG_TEST_PROP:
+      test->value = g_value_get_int (value);
+      break;
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+  }
+}
+
+static void
+g_test_get_property (GObject * object, guint prop_id,
+    GValue * value, GParamSpec * pspec)
+{
+  GTest *test;
+
+  test = G_TEST (object);
+
+  switch (prop_id) {
+    case ARG_TEST_PROP:
+      g_value_set_int (value, test->value);
+      break;
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+  }
+}
+
+static void
+g_test_do_signal1 (GTest * test)
+{
+  g_signal_emit (G_OBJECT (test), g_test_signals[TEST_SIGNAL1], 0, 0);
+}
+
+static void
+signal2_handler (GTest * test, gint anint)
+{
+}
+
+static void
+g_test_do_signal2 (GTest * test)
+{
+  g_signal_emit (G_OBJECT (test), g_test_signals[TEST_SIGNAL2], 0, 0);
+}
+
+static void
+g_test_do_prop (GTest * test)
+{
+  test->value = g_rand_int (rand);
+  g_object_notify (G_OBJECT (test), "test-prop");
+}
+
+static gpointer
+run_thread (GTest * test)
+{
+  gint i = 0;
+
+  while (!stopping) {
+    if (TESTNUM == 1)
+      g_test_do_signal1 (test);
+    if (TESTNUM == 2)
+      g_test_do_signal2 (test);
+    if (TESTNUM == 3)
+      g_test_do_prop (test);
+    if ((i++ % 100000) == 0) {
+      g_print (".");
+      g_usleep (1);             /* context switch */
+    }
+  }
+
+  return NULL;
+}
+
+static void
+notify (GObject *object, GParamSpec *spec, gpointer user_data)
+{
+  gint value;
+
+  g_object_get (object, "test-prop", &value, NULL);
+  //g_print ("+ %d", value);
+}
+
+int
+main (int argc, char **argv)
+{
+  gint i;
+  GTest *test1, *test2;
+  GArray *test_threads;
+
+  g_thread_init (NULL);
+  g_type_init ();
+
+  test1 = g_object_new (G_TYPE_TEST, NULL);
+  test2 = g_object_new (G_TYPE_TEST, NULL);
+
+  g_signal_connect (test1, "notify::test-prop", notify, NULL);
+  g_signal_connect (test1, "test-signal1", notify, NULL);
+  g_signal_connect (test1, "test-signal2", notify, NULL);
+
+  test_threads = g_array_new (FALSE, FALSE, sizeof (GThread *));
+
+  stopping = FALSE;
+
+  for (i = 0; i < 20; i++) {
+    GThread *thread;
+
+    thread = g_thread_create ((GThreadFunc) run_thread, test1, TRUE, NULL);
+    g_array_append_val (test_threads, thread);
+
+    thread = g_thread_create ((GThreadFunc) run_thread, test2, TRUE, NULL);
+    g_array_append_val (test_threads, thread);
+  }
+  sleep (5);
+
+  stopping = TRUE;
+
+  g_print ("\nstopping\n");
+
+  /* join all threads */
+  for (i = 0; i < 40; i++) {
+    GThread *thread;
+
+    thread = g_array_index (test_threads, GThread *, i);
+    g_thread_join (thread);
+  }
+
+  g_print ("stopped\n");
+
+  return 0;
+}