[PATCH v4 25/27] selftests: ntsync: Add a stress test for contended waits.

Elizabeth Figura
2024-04-16T01:10:31Z

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: Elizabeth Figura <zfigura@codeweavers.com>
---
.../testing/selftests/drivers/ntsync/ntsync.c | 74 +++++++++++++++++++
1 file changed, 74 insertions(+)

diff --git a/tools/testing/selftests/drivers/ntsync/ntsync.c b/tools/testing/selftests/drivers/ntsync/ntsync.c
index 968874d7e325..5fa2c9a0768c 100644
--- a/tools/testing/selftests/drivers/ntsync/ntsync.c
+++ b/tools/testing/selftests/drivers/ntsync/ntsync.c
@@ -1330,4 +1330,78 @@ 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;
+ ret = ioctl(stress_device, NTSYNC_IOC_CREATE_MUTEX, &mutex_args);
+ EXPECT_EQ(0, ret);
+ stress_mutex = mutex_args.mutex;
+
+ event_args.manual = 1;
+ event_args.signaled = 0;
+ ret = ioctl(stress_device, NTSYNC_IOC_CREATE_EVENT, &event_args);
+ EXPECT_EQ(0, ret);
+ stress_start_event = event_args.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
--
2.43.0