glib/tests/refcount/closures.c
Simon McVittie cb98e37357 closures test: Avoid timeout on ARM64 CPUs
Closures use a 16-bit atomic reference count, which is really slow
on certain ARM64 CPUs such as the Cortex-A57 (glib#1316). This is
non-trivial to solve, since the public struct field cannot be enlarged
to 32-bit while preserving ABI, and 16-bit atomic operations would be new
(and rather niche) API.

Until this can be solved properly (hopefully in GLib 2.59.x), cut down
the number of signal emission cycles and bump up the timeout in the
Meson build system, so that builds won't time out. We can't just take
another zero off the number of signal emission cycles, as was done in the
original version of this patch in Debian, because if we do that it can
result in test failures when the main thread starves the other threads.

ARM64 CPUs are backwards-compatible with 32-bit ARM, and the same
slowdown can be seen when building and testing 32-bit code on these
CPUs, so check for both 32- and 64-bit ARM.

Bug-Debian: https://bugs.debian.org/880883
Co-authored-by: Iain Lane <laney@debian.org>
Signed-off-by: Simon McVittie <smcv@debian.org>
2018-11-06 13:48:34 +00:00

306 lines
8.5 KiB
C

/* Copyright (C) 2005 Imendio AB
*
* This software is provided "as is"; redistribution and modification
* is permitted, provided that the following disclaimer is retained.
*
* This software 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.
* In no event shall the authors or contributors be liable for any
* direct, indirect, incidental, special, exemplary, or consequential
* damages (including, but not limited to, procurement of substitute
* goods or services; loss of use, data, or profits; or business
* interruption) however caused and on any theory of liability, whether
* in contract, strict liability, or tort (including negligence or
* otherwise) arising in any way out of the use of this software, even
* if advised of the possibility of such damage.
*/
#include <glib-object.h>
#ifdef G_OS_UNIX
#include <unistd.h>
#endif
#define TEST_POINTER1 ((gpointer) 47)
#define TEST_POINTER2 ((gpointer) 49)
#define TEST_INT1 (-77)
#define TEST_INT2 (78)
/* --- GTest class --- */
typedef struct {
GObject object;
gint value;
gpointer test_pointer1;
gpointer test_pointer2;
} GTest;
typedef struct {
GObjectClass parent_class;
void (*test_signal1) (GTest * test, gint an_int);
void (*test_signal2) (GTest * test, gint an_int);
} GTestClass;
#define G_TYPE_TEST (my_test_get_type ())
#define MY_TEST(test) (G_TYPE_CHECK_INSTANCE_CAST ((test), G_TYPE_TEST, GTest))
#define MY_IS_TEST(test) (G_TYPE_CHECK_INSTANCE_TYPE ((test), G_TYPE_TEST))
#define MY_TEST_CLASS(tclass) (G_TYPE_CHECK_CLASS_CAST ((tclass), G_TYPE_TEST, GTestClass))
#define MY_IS_TEST_CLASS(tclass) (G_TYPE_CHECK_CLASS_TYPE ((tclass), G_TYPE_TEST))
#define MY_TEST_GET_CLASS(test) (G_TYPE_INSTANCE_GET_CLASS ((test), G_TYPE_TEST, GTestClass))
static GType my_test_get_type (void);
G_DEFINE_TYPE (GTest, my_test, G_TYPE_OBJECT)
/* --- variables --- */
static volatile gboolean stopping = FALSE;
static guint test_signal1 = 0;
static guint test_signal2 = 0;
static gboolean seen_signal_handler = FALSE;
static gboolean seen_cleanup = FALSE;
static gboolean seen_test_int1 = FALSE;
static gboolean seen_test_int2 = FALSE;
static gboolean seen_thread1 = FALSE;
static gboolean seen_thread2 = FALSE;
/* --- functions --- */
static void
my_test_init (GTest * test)
{
g_print ("init %p\n", test);
test->value = 0;
test->test_pointer1 = TEST_POINTER1;
test->test_pointer2 = TEST_POINTER2;
}
enum {
ARG_0,
ARG_TEST_PROP
};
static void
my_test_set_property (GObject *object,
guint prop_id,
const GValue *value,
GParamSpec *pspec)
{
GTest *test = MY_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
my_test_get_property (GObject *object,
guint prop_id,
GValue *value,
GParamSpec *pspec)
{
GTest *test = MY_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
my_test_test_signal2 (GTest *test,
gint an_int)
{
}
static void
my_test_emit_test_signal1 (GTest *test,
gint vint)
{
g_signal_emit (G_OBJECT (test), test_signal1, 0, vint);
}
static void
my_test_emit_test_signal2 (GTest *test,
gint vint)
{
g_signal_emit (G_OBJECT (test), test_signal2, 0, vint);
}
static void
my_test_class_init (GTestClass *klass)
{
GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
gobject_class->set_property = my_test_set_property;
gobject_class->get_property = my_test_get_property;
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);
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 = my_test_test_signal2;
}
static inline guint32
quick_rand32 (void)
{
static guint32 accu = 2147483563;
accu = 1664525 * accu + 1013904223;
return accu;
}
static void
test_closure (GClosure *closure)
{
/* try to produce high contention in closure->ref_count */
guint i = 0, n = quick_rand32() % 199;
for (i = 0; i < n; i++)
g_closure_ref (closure);
g_closure_sink (closure); /* NOP */
for (i = 0; i < n; i++)
g_closure_unref (closure);
}
static gpointer
thread1_main (gpointer data)
{
GClosure *closure = data;
while (!stopping)
{
static guint count = 0;
test_closure (closure);
if (++count % 10000 == 0)
{
g_printerr ("c");
g_thread_yield(); /* force context switch */
seen_thread1 = TRUE;
}
}
return NULL;
}
static gpointer
thread2_main (gpointer data)
{
GClosure *closure = data;
while (!stopping)
{
static guint count = 0;
test_closure (closure);
if (++count % 10000 == 0)
{
g_printerr ("C");
g_thread_yield(); /* force context switch */
seen_thread2 = TRUE;
}
}
return NULL;
}
static void
test_signal_handler (GTest *test,
gint vint,
gpointer data)
{
g_assert (data == TEST_POINTER2);
g_assert (test->test_pointer1 == TEST_POINTER1);
seen_signal_handler = TRUE;
seen_test_int1 |= vint == TEST_INT1;
seen_test_int2 |= vint == TEST_INT2;
}
static void
destroy_data (gpointer data,
GClosure *closure)
{
seen_cleanup = data == TEST_POINTER2;
g_assert (closure->ref_count == 0);
}
static void
test_emissions (GTest *test)
{
my_test_emit_test_signal1 (test, TEST_INT1);
my_test_emit_test_signal2 (test, TEST_INT2);
}
int
main (int argc,
char **argv)
{
GThread *thread1, *thread2;
GClosure *closure;
GTest *object;
guint i;
g_print ("START: %s\n", argv[0]);
g_log_set_always_fatal (G_LOG_LEVEL_WARNING | G_LOG_LEVEL_CRITICAL | g_log_set_always_fatal (G_LOG_FATAL_MASK));
object = g_object_new (G_TYPE_TEST, NULL);
closure = g_cclosure_new (G_CALLBACK (test_signal_handler), TEST_POINTER2, destroy_data);
g_signal_connect_closure (object, "test-signal1", closure, FALSE);
g_signal_connect_closure (object, "test-signal2", closure, FALSE);
stopping = FALSE;
thread1 = g_thread_create (thread1_main, closure, TRUE, NULL);
thread2 = g_thread_create (thread2_main, closure, TRUE, NULL);
/* The 16-bit compare-and-swap operations currently used for closure
* refcounts are really slow on some ARM CPUs, notably Cortex-A57.
* Reduce the number of iterations so that the test completes in a
* finite time, but don't reduce it so much that the main thread
* starves the other threads and causes a test failure.
*
* https://gitlab.gnome.org/GNOME/glib/issues/1316
* aka https://bugs.debian.org/880883 */
#if defined(__aarch64__) || defined(__arm__)
for (i = 0; i < 100000; i++)
#else
for (i = 0; i < 1000000; i++)
#endif
{
static guint count = 0;
test_emissions (object);
if (++count % 10000 == 0)
{
g_printerr (".\n");
g_thread_yield(); /* force context switch */
}
}
stopping = TRUE;
g_print ("\nstopping\n");
/* wait for thread shutdown */
g_thread_join (thread1);
g_thread_join (thread2);
/* finalize object, destroy signals, run cleanup code */
g_object_unref (object);
g_print ("stopped\n");
g_assert (seen_thread1 != FALSE);
g_assert (seen_thread2 != FALSE);
g_assert (seen_test_int1 != FALSE);
g_assert (seen_test_int2 != FALSE);
g_assert (seen_signal_handler != FALSE);
g_assert (seen_cleanup != FALSE);
return 0;
}