ck_rwlock: Add basic RTM interface to rwlock.

It is possible this will be moved to a self-contained file.
For a majority of architectures, RTM is an unnecessary
implementation-specific optimization.

include/ck_rwlock.h

@@ -58,6 +58,21 @@ ck_rwlock_write_unlock(ck_rwlock_t *rw)
 	return;
 }
 
+#ifdef CK_F_PR_RTM
+CK_CC_INLINE static void
+ck_rwlock_write_unlock_rtm(ck_rwlock_t *rw)
+{
+
+	if (ck_pr_load_uint(&rw->writer) == 0) {
+		ck_pr_rtm_end();
+		return;
+	}
+
+	ck_rwlock_write_unlock(rw);
+	return;
+}
+#endif /* CK_F_PR_RTM */
+
 CK_CC_INLINE static void
 ck_rwlock_write_downgrade(ck_rwlock_t *rw)
 {
@@ -67,6 +82,25 @@ ck_rwlock_write_downgrade(ck_rwlock_t *rw)
 	return;
 }
 
+#ifdef CK_F_PR_RTM
+CK_CC_INLINE static void
+ck_rwlock_write_downgrade_rtm(ck_rwlock_t *rw)
+{
+
+	if (ck_pr_load_uint(&rw->writer) != 0) {
+		ck_rwlock_write_downgrade(rw);
+		return;
+	}
+
+	/*
+	 * Both reader and writer counters are in read-set. A transactional
+	 * abort will occur in the presence of another writer. Inner-most
+	 * read_unlock call will attempt a transactional commit.
+	 */
+	return;
+}
+#endif /* CK_F_PR_RTM */
+
 CK_CC_INLINE static bool
 ck_rwlock_write_trylock(ck_rwlock_t *rw)
 {
@@ -84,6 +118,27 @@ ck_rwlock_write_trylock(ck_rwlock_t *rw)
 	return true;
 }
 
+#ifdef CK_F_PR_RTM
+CK_CC_INLINE static bool
+ck_rwlock_write_trylock_rtm(ck_rwlock_t *rw)
+{
+	bool r;
+
+	if (ck_pr_rtm_begin() != CK_PR_RTM_STARTED) {
+		return ck_rwlock_write_trylock(rw);
+	}
+
+	r = ck_pr_load_uint(&rw->writer) != 0;
+
+	ck_pr_fence_load();
+
+	if (r | (ck_pr_load_uint(&rw->n_readers) != 0))
+		ck_pr_rtm_abort(0);
+
+	return true;
+}
+#endif /* CK_F_PR_RTM */
+
 CK_CC_INLINE static void
 ck_rwlock_write_lock(ck_rwlock_t *rw)
 {
@@ -99,6 +154,28 @@ ck_rwlock_write_lock(ck_rwlock_t *rw)
 	return;
 }
 
+#ifdef CK_F_PR_RTM
+CK_CC_INLINE static void
+ck_rwlock_write_lock_rtm(ck_rwlock_t *rw)
+{
+	bool r;
+
+	if (ck_pr_rtm_begin() != CK_PR_RTM_STARTED) {
+		ck_rwlock_write_lock(rw);
+		return;
+	}
+
+	r = ck_pr_load_uint(&rw->writer) != 0;
+
+	ck_pr_fence_load();
+
+	if (r | (ck_pr_load_uint(&rw->n_readers) != 0))
+		ck_pr_rtm_abort(0);
+
+	return;
+}
+#endif /* CK_F_PR_RTM */
+
 CK_CC_INLINE static bool
 ck_rwlock_read_trylock(ck_rwlock_t *rw)
 {
@@ -141,6 +218,7 @@ ck_rwlock_read_lock(ck_rwlock_t *rw)
 
 		if (ck_pr_load_uint(&rw->writer) == 0)
 			break;
+
 		ck_pr_dec_uint(&rw->n_readers);
 	}
 
@@ -149,6 +227,23 @@ ck_rwlock_read_lock(ck_rwlock_t *rw)
 	return;
 }
 
+#ifdef CK_F_PR_RTM
+CK_CC_INLINE static void
+ck_rwlock_read_lock_rtm(ck_rwlock_t *rw)
+{
+
+	if (ck_pr_rtm_begin() == CK_PR_RTM_STARTED) {
+		if (ck_pr_load_uint(&rw->writer) != 0)
+			ck_pr_rtm_abort(0);
+
+		return;
+	}
+
+	ck_rwlock_read_lock(rw);
+	return;
+}
+#endif /* CK_F_PR_RTM */
+
 CK_CC_INLINE static void
 ck_rwlock_read_unlock(ck_rwlock_t *rw)
 {
@@ -158,6 +253,21 @@ ck_rwlock_read_unlock(ck_rwlock_t *rw)
 	return;
 }
 
+#ifdef CK_F_PR_RTM
+CK_CC_INLINE static void
+ck_rwlock_read_unlock_rtm(ck_rwlock_t *rw)
+{
+
+	if (ck_pr_load_uint(&rw->n_readers) == 0) {
+		ck_pr_rtm_end();
+	} else {
+		ck_rwlock_read_unlock(rw);
+	}
+
+	return;
+}
+#endif /* CK_F_PR_RTM */
+
 /*
  * Recursive writer reader-writer lock implementation.
  */
@@ -251,3 +361,4 @@ ck_rwlock_recursive_read_unlock(ck_rwlock_recursive_t *rw)
 }
 
 #endif /* _CK_RWLOCK_H */
+

regressions/ck_rwlock/benchmark/latency.c

@@ -51,7 +51,22 @@ main(void)
 		ck_rwlock_write_unlock(&rwlock);
 	}
 	e_b = rdtsc();
-	printf("WRITE: rwlock   %15" PRIu64 "\n", (e_b - s_b) / STEPS);
+	printf("       WRITE: rwlock   %15" PRIu64 "\n", (e_b - s_b) / STEPS);
+
+#ifdef CK_F_PR_RTM
+	for (i = 0; i < STEPS; i++) {
+		ck_rwlock_write_lock_rtm(&rwlock);
+		ck_rwlock_write_unlock_rtm(&rwlock);
+	}
+
+	s_b = rdtsc();
+	for (i = 0; i < STEPS; i++) {
+		ck_rwlock_write_lock_rtm(&rwlock);
+		ck_rwlock_write_unlock_rtm(&rwlock);
+	}
+	e_b = rdtsc();
+	printf(" (rtm) WRITE: rwlock   %15" PRIu64 "\n", (e_b - s_b) / STEPS);
+#endif /* CK_F_PR_RTM */
 
 	for (i = 0; i < STEPS; i++) {
 		ck_rwlock_read_lock(&rwlock);
@@ -64,8 +79,23 @@ main(void)
 		ck_rwlock_read_unlock(&rwlock);
 	}
 	e_b = rdtsc();
-	printf("READ:  rwlock   %15" PRIu64 "\n", (e_b - s_b) / STEPS);
+	printf("       READ:  rwlock   %15" PRIu64 "\n", (e_b - s_b) / STEPS);
+
+#ifdef CK_F_PR_RTM
+	for (i = 0; i < STEPS; i++) {
+		ck_rwlock_read_lock_rtm(&rwlock);
+		ck_rwlock_read_unlock_rtm(&rwlock);
+	}
+
+	s_b = rdtsc();
+	for (i = 0; i < STEPS; i++) {
+		ck_rwlock_read_lock_rtm(&rwlock);
+		ck_rwlock_read_unlock_rtm(&rwlock);
+	}
+	e_b = rdtsc();
+	printf(" (rtm) READ:  rwlock   %15" PRIu64 "\n", (e_b - s_b) / STEPS);
+#endif /* CK_F_PR_RTM */
 
-	return (0);
+	return 0;
 }
 

regressions/ck_rwlock/benchmark/throughput.c

@@ -41,11 +41,17 @@
 static int barrier;
 static int threads;
 static unsigned int flag CK_CC_CACHELINE;
-static ck_rwlock_t rwlock = CK_RWLOCK_INITIALIZER;
+static struct {
+	ck_rwlock_t lock;
+} rw CK_CC_CACHELINE = {
+	.lock = CK_RWLOCK_INITIALIZER
+};
+
 static struct affinity affinity;
 
+#ifdef CK_F_PR_RTM
 static void *
-thread_rwlock(void *pun)
+thread_lock_rtm(void *pun)
 {
 	uint64_t s_b, e_b, a, i;
 	uint64_t *value = pun;
@@ -61,38 +67,38 @@ thread_rwlock(void *pun)
 
 	for (i = 1, a = 0;; i++) {
 		s_b = rdtsc();
-		ck_rwlock_read_lock(&rwlock);
+		ck_rwlock_read_lock_rtm(&rw.lock);
-		ck_rwlock_read_unlock(&rwlock);
+		ck_rwlock_read_unlock_rtm(&rw.lock);
-		ck_rwlock_read_lock(&rwlock);
+		ck_rwlock_read_lock_rtm(&rw.lock);
-		ck_rwlock_read_unlock(&rwlock);
+		ck_rwlock_read_unlock_rtm(&rw.lock);
-		ck_rwlock_read_lock(&rwlock);
+		ck_rwlock_read_lock_rtm(&rw.lock);
-		ck_rwlock_read_unlock(&rwlock);
+		ck_rwlock_read_unlock_rtm(&rw.lock);
-		ck_rwlock_read_lock(&rwlock);
+		ck_rwlock_read_lock_rtm(&rw.lock);
-		ck_rwlock_read_unlock(&rwlock);
+		ck_rwlock_read_unlock_rtm(&rw.lock);
-		ck_rwlock_read_lock(&rwlock);
+		ck_rwlock_read_lock_rtm(&rw.lock);
-		ck_rwlock_read_unlock(&rwlock);
+		ck_rwlock_read_unlock_rtm(&rw.lock);
-		ck_rwlock_read_lock(&rwlock);
+		ck_rwlock_read_lock_rtm(&rw.lock);
-		ck_rwlock_read_unlock(&rwlock);
+		ck_rwlock_read_unlock_rtm(&rw.lock);
-		ck_rwlock_read_lock(&rwlock);
+		ck_rwlock_read_lock_rtm(&rw.lock);
-		ck_rwlock_read_unlock(&rwlock);
+		ck_rwlock_read_unlock_rtm(&rw.lock);
-		ck_rwlock_read_lock(&rwlock);
+		ck_rwlock_read_lock_rtm(&rw.lock);
-		ck_rwlock_read_unlock(&rwlock);
+		ck_rwlock_read_unlock_rtm(&rw.lock);
-		ck_rwlock_read_lock(&rwlock);
+		ck_rwlock_read_lock_rtm(&rw.lock);
-		ck_rwlock_read_unlock(&rwlock);
+		ck_rwlock_read_unlock_rtm(&rw.lock);
-		ck_rwlock_read_lock(&rwlock);
+		ck_rwlock_read_lock_rtm(&rw.lock);
-		ck_rwlock_read_unlock(&rwlock);
+		ck_rwlock_read_unlock_rtm(&rw.lock);
-		ck_rwlock_read_lock(&rwlock);
+		ck_rwlock_read_lock_rtm(&rw.lock);
-		ck_rwlock_read_unlock(&rwlock);
+		ck_rwlock_read_unlock_rtm(&rw.lock);
-		ck_rwlock_read_lock(&rwlock);
+		ck_rwlock_read_lock_rtm(&rw.lock);
-		ck_rwlock_read_unlock(&rwlock);
+		ck_rwlock_read_unlock_rtm(&rw.lock);
-		ck_rwlock_read_lock(&rwlock);
+		ck_rwlock_read_lock_rtm(&rw.lock);
-		ck_rwlock_read_unlock(&rwlock);
+		ck_rwlock_read_unlock_rtm(&rw.lock);
-		ck_rwlock_read_lock(&rwlock);
+		ck_rwlock_read_lock_rtm(&rw.lock);
-		ck_rwlock_read_unlock(&rwlock);
+		ck_rwlock_read_unlock_rtm(&rw.lock);
-		ck_rwlock_read_lock(&rwlock);
+		ck_rwlock_read_lock_rtm(&rw.lock);
-		ck_rwlock_read_unlock(&rwlock);
+		ck_rwlock_read_unlock_rtm(&rw.lock);
-		ck_rwlock_read_lock(&rwlock);
+		ck_rwlock_read_lock_rtm(&rw.lock);
-		ck_rwlock_read_unlock(&rwlock);
+		ck_rwlock_read_unlock_rtm(&rw.lock);
 		e_b = rdtsc();
 
 		a += (e_b - s_b) >> 4;
@@ -108,39 +114,87 @@ thread_rwlock(void *pun)
 	*value = (a / i);
 	return NULL;
 }
+#endif /* CK_F_PR_RTM */
 
-int
+static void *
-main(int argc, char *argv[])
+thread_lock(void *pun)
 {
-	int t;
+	uint64_t s_b, e_b, a, i;
-	pthread_t *p;
+	uint64_t *value = pun;
-	uint64_t *latency;
 
-	if (argc != 3) {
+	if (aff_iterate(&affinity) != 0) {
-		ck_error("Usage: throughput <delta> <threads>\n");
+		perror("ERROR: Could not affine thread");
+		exit(EXIT_FAILURE);
 	}
 
-	threads = atoi(argv[2]);
+	ck_pr_inc_int(&barrier);
-	if (threads <= 0) {
+	while (ck_pr_load_int(&barrier) != threads)
-		ck_error("ERROR: Threads must be a value > 0.\n");
+		ck_pr_stall();
-	}
 
-	p = malloc(sizeof(pthread_t) * threads);
+	for (i = 1, a = 0;; i++) {
-	if (p == NULL) {
+		s_b = rdtsc();
-		ck_error("ERROR: Failed to initialize thread.\n");
+		ck_rwlock_read_lock(&rw.lock);
-	}
+		ck_rwlock_read_unlock(&rw.lock);
+		ck_rwlock_read_lock(&rw.lock);
+		ck_rwlock_read_unlock(&rw.lock);
+		ck_rwlock_read_lock(&rw.lock);
+		ck_rwlock_read_unlock(&rw.lock);
+		ck_rwlock_read_lock(&rw.lock);
+		ck_rwlock_read_unlock(&rw.lock);
+		ck_rwlock_read_lock(&rw.lock);
+		ck_rwlock_read_unlock(&rw.lock);
+		ck_rwlock_read_lock(&rw.lock);
+		ck_rwlock_read_unlock(&rw.lock);
+		ck_rwlock_read_lock(&rw.lock);
+		ck_rwlock_read_unlock(&rw.lock);
+		ck_rwlock_read_lock(&rw.lock);
+		ck_rwlock_read_unlock(&rw.lock);
+		ck_rwlock_read_lock(&rw.lock);
+		ck_rwlock_read_unlock(&rw.lock);
+		ck_rwlock_read_lock(&rw.lock);
+		ck_rwlock_read_unlock(&rw.lock);
+		ck_rwlock_read_lock(&rw.lock);
+		ck_rwlock_read_unlock(&rw.lock);
+		ck_rwlock_read_lock(&rw.lock);
+		ck_rwlock_read_unlock(&rw.lock);
+		ck_rwlock_read_lock(&rw.lock);
+		ck_rwlock_read_unlock(&rw.lock);
+		ck_rwlock_read_lock(&rw.lock);
+		ck_rwlock_read_unlock(&rw.lock);
+		ck_rwlock_read_lock(&rw.lock);
+		ck_rwlock_read_unlock(&rw.lock);
+		ck_rwlock_read_lock(&rw.lock);
+		ck_rwlock_read_unlock(&rw.lock);
+		e_b = rdtsc();
 
-	latency = malloc(sizeof(uint64_t) * threads);
+		a += (e_b - s_b) >> 4;
-	if (latency == NULL) {
+
-		ck_error("ERROR: Failed to create latency buffer.\n");
+		if (ck_pr_load_uint(&flag) == 1)
+			break;
 	}
 
-	affinity.delta = atoi(argv[1]);
+	ck_pr_inc_int(&barrier);
+	while (ck_pr_load_int(&barrier) != threads * 2)
+		ck_pr_stall();
+
+	*value = (a / i);
+	return NULL;
+}
+
+static void
+rwlock_test(pthread_t *p, int d, uint64_t *latency, void *(*f)(void *), const char *label)
+{
+	int t;
+
+	ck_pr_store_int(&barrier, 0);
+	ck_pr_store_uint(&flag, 0);
+
+	affinity.delta = d;
 	affinity.request = 0;
 
-	fprintf(stderr, "Creating threads (rwlock)...");
+	fprintf(stderr, "Creating threads (%s)...", label);
 	for (t = 0; t < threads; t++) {
-		if (pthread_create(&p[t], NULL, thread_rwlock, latency + t) != 0) {
+		if (pthread_create(&p[t], NULL, f, latency + t) != 0) {
 			ck_error("ERROR: Could not create thread %d\n", t);
 		}
 	}
@@ -157,6 +211,44 @@ main(int argc, char *argv[])
 	for (t = 1; t <= threads; t++)
 		printf("%10u %20" PRIu64 "\n", t, latency[t - 1]);
 
-	return (0);
+	fprintf(stderr, "\n");
+	return;
+}
+
+
+int
+main(int argc, char *argv[])
+{
+	int d;
+	pthread_t *p;
+	uint64_t *latency;
+
+	if (argc != 3) {
+		ck_error("Usage: throughput <delta> <threads>\n");
+	}
+
+	threads = atoi(argv[2]);
+	if (threads <= 0) {
+		ck_error("ERROR: Threads must be a value > 0.\n");
+	}
+
+	p = malloc(sizeof(pthread_t) * threads);
+	if (p == NULL) {
+		ck_error("ERROR: Failed to initialize thread.\n");
+	}
+
+	latency = malloc(sizeof(uint64_t) * threads);
+	if (latency == NULL) {
+		ck_error("ERROR: Failed to create latency buffer.\n");
+	}
+
+	d = atoi(argv[1]);
+	rwlock_test(p, d, latency, thread_lock, "rwlock");
+
+#ifdef CK_F_PR_RTM
+	rwlock_test(p, d, latency, thread_lock_rtm, "rwlock, rtm");
+#endif /* CK_F_PR_RTM */
+
+	return 0;
 }
 

regressions/ck_rwlock/validate/validate.c

@@ -123,10 +123,156 @@ thread_recursive(void *null CK_CC_UNUSED)
 	return (NULL);
 }
 
+#ifdef CK_F_PR_RTM
+static void *
+thread_rtm_mix(void *null CK_CC_UNUSED)
+{
+	unsigned int i = ITERATE;
+	unsigned int l;
+
+        if (aff_iterate(&a)) {
+                perror("ERROR: Could not affine thread");
+                exit(EXIT_FAILURE);
+        }
+
+	while (i--) {
+		if (i & 1) {
+			ck_rwlock_write_lock_rtm(&lock);
+		} else {
+			ck_rwlock_write_lock(&lock);
+		}
+
+		{
+			l = ck_pr_load_uint(&locked);
+			if (l != 0) {
+				ck_error("ERROR [WR:%d]: %u != 0\n", __LINE__, l);
+			}
+
+			ck_pr_inc_uint(&locked);
+			ck_pr_inc_uint(&locked);
+			ck_pr_inc_uint(&locked);
+			ck_pr_inc_uint(&locked);
+			ck_pr_inc_uint(&locked);
+			ck_pr_inc_uint(&locked);
+			ck_pr_inc_uint(&locked);
+			ck_pr_inc_uint(&locked);
+
+			l = ck_pr_load_uint(&locked);
+			if (l != 8) {
+				ck_error("ERROR [WR:%d]: %u != 2\n", __LINE__, l);
+			}
+
+			ck_pr_dec_uint(&locked);
+			ck_pr_dec_uint(&locked);
+			ck_pr_dec_uint(&locked);
+			ck_pr_dec_uint(&locked);
+			ck_pr_dec_uint(&locked);
+			ck_pr_dec_uint(&locked);
+			ck_pr_dec_uint(&locked);
+			ck_pr_dec_uint(&locked);
+
+			l = ck_pr_load_uint(&locked);
+			if (l != 0) {
+				ck_error("ERROR [WR:%d]: %u != 0\n", __LINE__, l);
+			}
+		}
+
+		if (i & 1) {
+			ck_rwlock_write_unlock_rtm(&lock);
+		} else {
+			ck_rwlock_write_unlock(&lock);
+		}
+
+		if (i & 1) {
+			ck_rwlock_read_lock_rtm(&lock);
+		} else {
+			ck_rwlock_read_lock(&lock);
+		}
+
+		{
+			l = ck_pr_load_uint(&locked);
+			if (l != 0) {
+				ck_error("ERROR [RD:%d]: %u != 0\n", __LINE__, l);
+			}
+		}
+
+		if (i & 1) {
+			ck_rwlock_read_unlock_rtm(&lock);
+		} else {
+			ck_rwlock_read_unlock(&lock);
+		}
+	}
+
+	return (NULL);
+}
+
+static void *
+thread_rtm(void *null CK_CC_UNUSED)
+{
+	unsigned int i = ITERATE;
+	unsigned int l;
+
+        if (aff_iterate(&a)) {
+                perror("ERROR: Could not affine thread");
+                exit(EXIT_FAILURE);
+        }
+
+	while (i--) {
+		ck_rwlock_write_lock_rtm(&lock);
+		{
+			l = ck_pr_load_uint(&locked);
+			if (l != 0) {
+				ck_error("ERROR [WR:%d]: %u != 0\n", __LINE__, l);
+			}
+
+			ck_pr_inc_uint(&locked);
+			ck_pr_inc_uint(&locked);
+			ck_pr_inc_uint(&locked);
+			ck_pr_inc_uint(&locked);
+			ck_pr_inc_uint(&locked);
+			ck_pr_inc_uint(&locked);
+			ck_pr_inc_uint(&locked);
+			ck_pr_inc_uint(&locked);
+
+			l = ck_pr_load_uint(&locked);
+			if (l != 8) {
+				ck_error("ERROR [WR:%d]: %u != 2\n", __LINE__, l);
+			}
+
+			ck_pr_dec_uint(&locked);
+			ck_pr_dec_uint(&locked);
+			ck_pr_dec_uint(&locked);
+			ck_pr_dec_uint(&locked);
+			ck_pr_dec_uint(&locked);
+			ck_pr_dec_uint(&locked);
+			ck_pr_dec_uint(&locked);
+			ck_pr_dec_uint(&locked);
+
+			l = ck_pr_load_uint(&locked);
+			if (l != 0) {
+				ck_error("ERROR [WR:%d]: %u != 0\n", __LINE__, l);
+			}
+		}
+		ck_rwlock_write_unlock_rtm(&lock);
+
+		ck_rwlock_read_lock_rtm(&lock);
+		{
+			l = ck_pr_load_uint(&locked);
+			if (l != 0) {
+				ck_error("ERROR [RD:%d]: %u != 0\n", __LINE__, l);
+			}
+		}
+		ck_rwlock_read_unlock_rtm(&lock);
+	}
+
+	return (NULL);
+}
+#endif /* CK_F_PR_RTM */
+
 static void *
 thread(void *null CK_CC_UNUSED)
 {
-	int i = ITERATE;
+	unsigned int i = ITERATE;
 	unsigned int l;
 
         if (aff_iterate(&a)) {
@@ -185,11 +331,29 @@ thread(void *null CK_CC_UNUSED)
 	return (NULL);
 }
 
+static void
+rwlock_test(pthread_t *threads, void *(*f)(void *), const char *test)
+{
+	int i;
+
+	fprintf(stderr, "Creating threads (%s)...", test);
+	for (i = 0; i < nthr; i++) {
+		if (pthread_create(&threads[i], NULL, f, NULL)) {
+			ck_error("ERROR: Could not create thread %d\n", i);
+		}
+	}
+	fprintf(stderr, ".");
+
+	for (i = 0; i < nthr; i++)
+		pthread_join(threads[i], NULL);
+	fprintf(stderr, "done (passed)\n");
+	return;
+}
+
 int
 main(int argc, char *argv[])
 {
 	pthread_t *threads;
-	int i;
 
 	if (argc != 3) {
 		ck_error("Usage: validate <number of threads> <affinity delta>\n");
@@ -207,32 +371,12 @@ main(int argc, char *argv[])
 
 	a.delta = atoi(argv[2]);
 
-	fprintf(stderr, "Creating threads (mutual exclusion)...");
+	rwlock_test(threads, thread, "regular");
-	for (i = 0; i < nthr; i++) {
+#ifdef CK_F_PR_RTM
-		if (pthread_create(&threads[i], NULL, thread, NULL)) {
+	rwlock_test(threads, thread_rtm, "rtm");
-			ck_error("ERROR: Could not create thread %d\n", i);
+	rwlock_test(threads, thread_rtm_mix, "rtm-mix");
-		}
+#endif
-	}
+	rwlock_test(threads, thread_recursive, "recursive");
-	fprintf(stderr, "done\n");
+	return 0;
-
-	fprintf(stderr, "Waiting for threads to finish correctness regression...");
-	for (i = 0; i < nthr; i++)
-		pthread_join(threads[i], NULL);
-	fprintf(stderr, "done (passed)\n");
-
-	fprintf(stderr, "Creating threads (mutual exclusion, recursive)...");
-	for (i = 0; i < nthr; i++) {
-		if (pthread_create(&threads[i], NULL, thread_recursive, NULL)) {
-			ck_error("ERROR: Could not create thread %d\n", i);
-		}
-	}
-	fprintf(stderr, "done\n");
-
-	fprintf(stderr, "Waiting for threads to finish correctness regression...");
-	for (i = 0; i < nthr; i++)
-		pthread_join(threads[i], NULL);
-	fprintf(stderr, "done (passed)\n");
-
-	return (0);
 }