Commit a22860e5 authored by Elizabeth Figura's avatar Elizabeth Figura Committed by Greg Kroah-Hartman
Browse files

selftests: ntsync: Add a stress test for contended waits. 



Test a more realistic usage pattern, and one with heavy contention, in order to
actually exercise ntsync's internal synchronization.

This test has several threads in a tight loop acquiring a mutex, modifying some
shared data, and then releasing the mutex. At the end we check if the data is
consistent.

Signed-off-by: default avatarElizabeth Figura <zfigura@codeweavers.com>
Link: https://lore.kernel.org/r/20241213193511.457338-28-zfigura@codeweavers.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent c52b9cb1

tools/testing/selftests/drivers/ntsync/ntsync.c

+72 −0
Original line number Diff line number Diff line
@@ -1268,4 +1268,76 @@ TEST(alert_all) 
	close(fd);

}



#define STRESS_LOOPS 10000

#define STRESS_THREADS 4



static unsigned int stress_counter;

static int stress_device, stress_start_event, stress_mutex;



static void *stress_thread(void *arg)

{

	struct ntsync_wait_args wait_args = {0};

	__u32 index, count, i;

	int ret;



	wait_args.timeout = UINT64_MAX;

	wait_args.count = 1;

	wait_args.objs = (uintptr_t)&stress_start_event;

	wait_args.owner = gettid();

	wait_args.index = 0xdeadbeef;



	ioctl(stress_device, NTSYNC_IOC_WAIT_ANY, &wait_args);



	wait_args.objs = (uintptr_t)&stress_mutex;



	for (i = 0; i < STRESS_LOOPS; ++i) {

		ioctl(stress_device, NTSYNC_IOC_WAIT_ANY, &wait_args);



		++stress_counter;



		unlock_mutex(stress_mutex, wait_args.owner, &count);

	}



	return NULL;

}



TEST(stress_wait)

{

	struct ntsync_event_args event_args;

	struct ntsync_mutex_args mutex_args;

	pthread_t threads[STRESS_THREADS];

	__u32 signaled, i;

	int ret;



	stress_device = open("/dev/ntsync", O_CLOEXEC | O_RDONLY);

	ASSERT_LE(0, stress_device);



	mutex_args.owner = 0;

	mutex_args.count = 0;

	stress_mutex = ioctl(stress_device, NTSYNC_IOC_CREATE_MUTEX, &mutex_args);

	EXPECT_LE(0, stress_mutex);



	event_args.manual = 1;

	event_args.signaled = 0;

	stress_start_event = ioctl(stress_device, NTSYNC_IOC_CREATE_EVENT, &event_args);

	EXPECT_LE(0, stress_start_event);



	for (i = 0; i < STRESS_THREADS; ++i)

		pthread_create(&threads[i], NULL, stress_thread, NULL);



	ret = ioctl(stress_start_event, NTSYNC_IOC_EVENT_SET, &signaled);

	EXPECT_EQ(0, ret);



	for (i = 0; i < STRESS_THREADS; ++i) {

		ret = pthread_join(threads[i], NULL);

		EXPECT_EQ(0, ret);

	}



	EXPECT_EQ(STRESS_LOOPS * STRESS_THREADS, stress_counter);



	close(stress_start_event);

	close(stress_mutex);

	close(stress_device);

}



TEST_HARNESS_MAIN