diff --git a/lib/libthr/thread/thr_mutex.c b/lib/libthr/thread/thr_mutex.c
--- a/lib/libthr/thread/thr_mutex.c
+++ b/lib/libthr/thread/thr_mutex.c
@@ -81,7 +81,6 @@
 static int	mutex_lock_sleep(struct pthread *, pthread_mutex_t,
 				const struct timespec *);
 static void	mutex_init_robust(struct pthread *curthread);
-static int	mutex_qidx(struct pthread_mutex *m);
 static bool	is_robust_mutex(struct pthread_mutex *m);
 static bool	is_pshared_mutex(struct pthread_mutex *m);
 
@@ -242,6 +241,7 @@
 {
 
 	pmutex->m_flags = attr->m_type;
+	pmutex->m_qidx = TMQ_NORM;
 	pmutex->m_count = 0;
 	pmutex->m_spinloops = 0;
 	pmutex->m_yieldloops = 0;
@@ -272,6 +272,8 @@
 		    _thr_spinloops ? _thr_spinloops: MUTEX_ADAPTIVE_SPINS;
 		pmutex->m_yieldloops = _thr_yieldloops;
 	}
+	if ((pmutex->m_lock.m_flags & UMUTEX_PRIO_PROTECT) != 0)
+		pmutex->m_qidx = (is_robust_mutex(pmutex) ? TMQ_ROBUST_PP : TMQ_NORM_PP);
 }
 
 static int
@@ -324,7 +326,7 @@
 {
 	struct pthread_mutex *m2;
 
-	m2 = TAILQ_LAST(&curthread->mq[mutex_qidx(m)], mutex_queue);
+	m2 = TAILQ_LAST(&curthread->mq[m->m_qidx], mutex_queue);
 	if (m2 != NULL)
 		m->m_lock.m_ceilings[1] = m2->m_lock.m_ceilings[0];
 	else
@@ -500,15 +502,6 @@
 	return (ret);
 }
 
-static int
-mutex_qidx(struct pthread_mutex *m)
-{
-
-	if ((m->m_lock.m_flags & UMUTEX_PRIO_PROTECT) == 0)
-		return (TMQ_NORM);
-	return (is_robust_mutex(m) ? TMQ_ROBUST_PP : TMQ_NORM_PP);
-}
-
 /*
  * Both enqueue_mutex() and dequeue_mutex() operate on the
  * thread-private linkage of the locked mutexes and on the robust
@@ -527,15 +520,13 @@
 {
 	struct pthread_mutex *m1;
 	uintptr_t *rl;
-	int qidx;
 
 	/* Add to the list of owned mutexes: */
 	if (error != EOWNERDEAD)
 		mutex_assert_not_owned(curthread, m);
-	qidx = mutex_qidx(m);
-	TAILQ_INSERT_TAIL(&curthread->mq[qidx], m, m_qe);
+	TAILQ_INSERT_TAIL(&curthread->mq[m->m_qidx], m, m_qe);
 	if (!is_pshared_mutex(m))
-		TAILQ_INSERT_TAIL(&curthread->mq[qidx + 1], m, m_pqe);
+		TAILQ_INSERT_TAIL(&curthread->mq[m->m_qidx + 1], m, m_pqe);
 	if (is_robust_mutex(m)) {
 		rl = is_pshared_mutex(m) ? &curthread->robust_list :
 		    &curthread->priv_robust_list;
@@ -557,10 +548,8 @@
 dequeue_mutex(struct pthread *curthread, struct pthread_mutex *m)
 {
 	struct pthread_mutex *mp, *mn;
-	int qidx;
 
 	mutex_assert_is_owned(m);
-	qidx = mutex_qidx(m);
 	if (is_robust_mutex(m)) {
 		mp = m->m_rb_prev;
 		if (mp == NULL) {
@@ -581,9 +570,9 @@
 		m->m_lock.m_rb_lnk = 0;
 		m->m_rb_prev = NULL;
 	}
-	TAILQ_REMOVE(&curthread->mq[qidx], m, m_qe);
+	TAILQ_REMOVE(&curthread->mq[m->m_qidx], m, m_qe);
 	if (!is_pshared_mutex(m))
-		TAILQ_REMOVE(&curthread->mq[qidx + 1], m, m_pqe);
+		TAILQ_REMOVE(&curthread->mq[m->m_qidx + 1], m, m_pqe);
 	if ((m->m_lock.m_flags & UMUTEX_PRIO_PROTECT) != 0)
 		set_inherited_priority(curthread, m);
 	mutex_init_link(m);
@@ -596,7 +585,7 @@
 
 	*m = *mutex;
 	ret = 0;
-	if (*m == THR_PSHARED_PTR) {
+	if (__predict_false(*m == THR_PSHARED_PTR)) {
 		*m = __thr_pshared_offpage(mutex, 0);
 		if (*m == NULL)
 			ret = EINVAL;
@@ -714,7 +703,7 @@
 	return (ret);
 }
 
-static inline int
+static __always_inline int
 mutex_lock_common(struct pthread_mutex *m, const struct timespec *abstime,
     bool cvattach, bool rb_onlist)
 {
@@ -728,7 +717,7 @@
 	if (!rb_onlist)
 		robust = _mutex_enter_robust(curthread, m);
 	ret = _thr_umutex_trylock2(&m->m_lock, TID(curthread));
-	if (ret == 0 || ret == EOWNERDEAD) {
+	if (__predict_true(ret == 0) || ret == EOWNERDEAD) {
 		enqueue_mutex(curthread, m, ret);
 		if (ret == EOWNERDEAD)
 			m->m_lock.m_flags |= UMUTEX_NONCONSISTENT;
@@ -737,7 +726,7 @@
 	}
 	if (!rb_onlist && robust)
 		_mutex_leave_robust(curthread, m);
-	if (ret != 0 && ret != EOWNERDEAD &&
+	if (__predict_false(ret != 0) && ret != EOWNERDEAD &&
 	    (m->m_flags & PMUTEX_FLAG_PRIVATE) != 0 && !cvattach)
 		THR_CRITICAL_LEAVE(curthread);
 	return (ret);
@@ -951,7 +940,7 @@
 	return (ret);
 }
 
-static int
+static __always_inline int
 mutex_unlock_common(struct pthread_mutex *m, bool cv, int *mtx_defer)
 {
 	struct pthread *curthread;
@@ -979,11 +968,9 @@
 	    PTHREAD_MUTEX_RECURSIVE && m->m_count > 0)) {
 		m->m_count--;
 	} else {
-		if ((m->m_flags & PMUTEX_FLAG_DEFERRED) != 0) {
-			deferred = 1;
+		deferred = ((m->m_flags & PMUTEX_FLAG_DEFERRED) != 0);
+		if (deferred)
 			m->m_flags &= ~PMUTEX_FLAG_DEFERRED;
-        	} else
-			deferred = 0;
 
 		robust = _mutex_enter_robust(curthread, m);
 		dequeue_mutex(curthread, m);
@@ -1033,7 +1020,7 @@
 	struct pthread *curthread;
 	struct pthread_mutex *m, *m1, *m2;
 	struct mutex_queue *q, *qp;
-	int qidx, ret;
+	int ret;
 
 	if (*mutex == THR_PSHARED_PTR) {
 		m = __thr_pshared_offpage(mutex, 0);
@@ -1059,9 +1046,8 @@
 		m2 = TAILQ_NEXT(m, m_qe);
 		if ((m1 != NULL && m1->m_lock.m_ceilings[0] > (u_int)ceiling) ||
 		    (m2 != NULL && m2->m_lock.m_ceilings[0] < (u_int)ceiling)) {
-			qidx = mutex_qidx(m);
-			q = &curthread->mq[qidx];
-			qp = &curthread->mq[qidx + 1];
+			q = &curthread->mq[m->m_qidx];
+			qp = &curthread->mq[m->m_qidx + 1];
 			TAILQ_REMOVE(q, m, m_qe);
 			if (!is_pshared_mutex(m))
 				TAILQ_REMOVE(qp, m, m_pqe);
diff --git a/lib/libthr/thread/thr_private.h b/lib/libthr/thread/thr_private.h
--- a/lib/libthr/thread/thr_private.h
+++ b/lib/libthr/thread/thr_private.h
@@ -169,6 +169,7 @@
 	 */
 	struct umutex			m_lock;
 	int				m_flags;
+	int				m_qidx;
 	int				m_count;
 	int				m_spinloops;
 	int				m_yieldloops;