diff --git a/sys/kern/kern_lockstat.c b/sys/kern/kern_lockstat.c
index eb7e177..b948d15 100644
--- a/sys/kern/kern_lockstat.c
+++ b/sys/kern/kern_lockstat.c
@@ -34,9 +34,10 @@
 
 #ifdef KDTRACE_HOOKS
 
-#include <sys/time.h>
 #include <sys/types.h>
+#include <sys/lock.h>
 #include <sys/lockstat.h>
+#include <sys/time.h>
 
 /*
  * The following must match the type definition of dtrace_probe.  It is  
@@ -48,13 +49,15 @@ void (*lockstat_probe_func)(uint32_t, uintptr_t, uintptr_t,
 int lockstat_enabled = 0;
 
 uint64_t 
-lockstat_nsecs(void)
+lockstat_nsecs(struct lock_object *lo)
 {
 	struct bintime bt;
 	uint64_t ns;
 
 	if (!lockstat_enabled)
 		return (0);
+	if ((lo->lo_flags & LO_NOPROFILE) != 0)
+		return (0);
 
 	binuptime(&bt);
 	ns = bt.sec * (uint64_t)1000000000;
diff --git a/sys/kern/kern_mutex.c b/sys/kern/kern_mutex.c
index 72fc434..dac97f6 100644
--- a/sys/kern/kern_mutex.c
+++ b/sys/kern/kern_mutex.c
@@ -416,7 +416,7 @@ __mtx_lock_sleep(volatile uintptr_t *c, uintptr_t tid, int opts,
 		    "_mtx_lock_sleep: %s contested (lock=%p) at %s:%d",
 		    m->lock_object.lo_name, (void *)m->mtx_lock, file, line);
 #ifdef KDTRACE_HOOKS
-	all_time -= lockstat_nsecs();
+	all_time -= lockstat_nsecs(&m->lock_object);
 #endif
 
 	while (!_mtx_obtain_lock(m, tid)) {
@@ -513,16 +513,16 @@ __mtx_lock_sleep(volatile uintptr_t *c, uintptr_t tid, int opts,
 		 * Block on the turnstile.
 		 */
 #ifdef KDTRACE_HOOKS
-		sleep_time -= lockstat_nsecs();
+		sleep_time -= lockstat_nsecs(&m->lock_object);
 #endif
 		turnstile_wait(ts, mtx_owner(m), TS_EXCLUSIVE_QUEUE);
 #ifdef KDTRACE_HOOKS
-		sleep_time += lockstat_nsecs();
+		sleep_time += lockstat_nsecs(&m->lock_object);
 		sleep_cnt++;
 #endif
 	}
 #ifdef KDTRACE_HOOKS
-	all_time += lockstat_nsecs();
+	all_time += lockstat_nsecs(&m->lock_object);
 #endif
 #ifdef KTR
 	if (cont_logged) {
@@ -600,7 +600,7 @@ _mtx_lock_spin_cookie(volatile uintptr_t *c, uintptr_t tid, int opts,
 #endif
 	lock_profile_obtain_lock_failed(&m->lock_object, &contested, &waittime);
 #ifdef KDTRACE_HOOKS
-	spin_time -= lockstat_nsecs();
+	spin_time -= lockstat_nsecs(&m->lock_object);
 #endif
 	while (!_mtx_obtain_lock(m, tid)) {
 
@@ -620,7 +620,7 @@ _mtx_lock_spin_cookie(volatile uintptr_t *c, uintptr_t tid, int opts,
 		spinlock_enter();
 	}
 #ifdef KDTRACE_HOOKS
-	spin_time += lockstat_nsecs();
+	spin_time += lockstat_nsecs(&m->lock_object);
 #endif
 
 	if (LOCK_LOG_TEST(&m->lock_object, opts))
@@ -630,7 +630,8 @@ _mtx_lock_spin_cookie(volatile uintptr_t *c, uintptr_t tid, int opts,
 
 	LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(LS_MTX_SPIN_LOCK_ACQUIRE, m,
 	    contested, waittime, (file), (line));
-	LOCKSTAT_RECORD1(LS_MTX_SPIN_LOCK_SPIN, m, spin_time);
+	if (spin_time != 0)
+		LOCKSTAT_RECORD1(LS_MTX_SPIN_LOCK_SPIN, m, spin_time);
 }
 #endif /* SMP */
 
@@ -655,7 +656,7 @@ thread_lock_flags_(struct thread *td, int opts, const char *file, int line)
 		return;
 
 #ifdef KDTRACE_HOOKS
-	spin_time -= lockstat_nsecs();
+	spin_time -= lockstat_nsecs(&td->td_lock->lock_object);
 #endif
 	for (;;) {
 retry:
@@ -703,7 +704,7 @@ retry:
 		__mtx_unlock_spin(m);	/* does spinlock_exit() */
 	}
 #ifdef KDTRACE_HOOKS
-	spin_time += lockstat_nsecs();
+	spin_time += lockstat_nsecs(&m->lock_object);
 #endif
 	if (m->mtx_recurse == 0)
 		LOCKSTAT_PROFILE_OBTAIN_LOCK_SUCCESS(LS_MTX_SPIN_LOCK_ACQUIRE,
diff --git a/sys/kern/kern_rwlock.c b/sys/kern/kern_rwlock.c
index f75912b..7553b07 100644
--- a/sys/kern/kern_rwlock.c
+++ b/sys/kern/kern_rwlock.c
@@ -378,7 +378,7 @@ __rw_rlock(volatile uintptr_t *c, const char *file, int line)
 	WITNESS_CHECKORDER(&rw->lock_object, LOP_NEWORDER, file, line, NULL);
 
 #ifdef KDTRACE_HOOKS
-	all_time -= lockstat_nsecs();
+	all_time -= lockstat_nsecs(&rw->lock_object);
 	state = rw->rw_lock;
 #endif
 	for (;;) {
@@ -532,11 +532,11 @@ __rw_rlock(volatile uintptr_t *c, const char *file, int line)
 			CTR2(KTR_LOCK, "%s: %p blocking on turnstile", __func__,
 			    rw);
 #ifdef KDTRACE_HOOKS
-		sleep_time -= lockstat_nsecs();
+		sleep_time -= lockstat_nsecs(&rw->lock_object);
 #endif
 		turnstile_wait(ts, rw_owner(rw), TS_SHARED_QUEUE);
 #ifdef KDTRACE_HOOKS
-		sleep_time += lockstat_nsecs();
+		sleep_time += lockstat_nsecs(&rw->lock_object);
 		sleep_cnt++;
 #endif
 		if (LOCK_LOG_TEST(&rw->lock_object, 0))
@@ -544,7 +544,7 @@ __rw_rlock(volatile uintptr_t *c, const char *file, int line)
 			    __func__, rw);
 	}
 #ifdef KDTRACE_HOOKS
-	all_time += lockstat_nsecs();
+	all_time += lockstat_nsecs(&rw->lock_object);
 	if (sleep_time)
 		LOCKSTAT_RECORD4(LS_RW_RLOCK_BLOCK, rw, sleep_time,
 		    LOCKSTAT_READER, (state & RW_LOCK_READ) == 0,
@@ -767,7 +767,7 @@ __rw_wlock_hard(volatile uintptr_t *c, uintptr_t tid, const char *file,
 		    rw->lock_object.lo_name, (void *)rw->rw_lock, file, line);
 
 #ifdef KDTRACE_HOOKS
-	all_time -= lockstat_nsecs();
+	all_time -= lockstat_nsecs(&rw->lock_object);
 	state = rw->rw_lock;
 #endif
 	while (!_rw_write_lock(rw, tid)) {
@@ -893,11 +893,11 @@ __rw_wlock_hard(volatile uintptr_t *c, uintptr_t tid, const char *file,
 			CTR2(KTR_LOCK, "%s: %p blocking on turnstile", __func__,
 			    rw);
 #ifdef KDTRACE_HOOKS
-		sleep_time -= lockstat_nsecs();
+		sleep_time -= lockstat_nsecs(&rw->lock_object);
 #endif
 		turnstile_wait(ts, rw_owner(rw), TS_EXCLUSIVE_QUEUE);
 #ifdef KDTRACE_HOOKS
-		sleep_time += lockstat_nsecs();
+		sleep_time += lockstat_nsecs(&rw->lock_object);
 		sleep_cnt++;
 #endif
 		if (LOCK_LOG_TEST(&rw->lock_object, 0))
@@ -908,7 +908,7 @@ __rw_wlock_hard(volatile uintptr_t *c, uintptr_t tid, const char *file,
 #endif
 	}
 #ifdef KDTRACE_HOOKS
-	all_time += lockstat_nsecs();
+	all_time += lockstat_nsecs(&rw->lock_object);
 	if (sleep_time)
 		LOCKSTAT_RECORD4(LS_RW_WLOCK_BLOCK, rw, sleep_time,
 		    LOCKSTAT_WRITER, (state & RW_LOCK_READ) == 0,
diff --git a/sys/kern/kern_sx.c b/sys/kern/kern_sx.c
index 91e8c60..7af1f32 100644
--- a/sys/kern/kern_sx.c
+++ b/sys/kern/kern_sx.c
@@ -541,7 +541,7 @@ _sx_xlock_hard(struct sx *sx, uintptr_t tid, int opts, const char *file,
 		    sx->lock_object.lo_name, (void *)sx->sx_lock, file, line);
 
 #ifdef KDTRACE_HOOKS
-	all_time -= lockstat_nsecs();
+	all_time -= lockstat_nsecs(&sx->lock_object);
 	state = sx->sx_lock;
 #endif
 	while (!atomic_cmpset_acq_ptr(&sx->sx_lock, SX_LOCK_UNLOCKED, tid)) {
@@ -691,7 +691,7 @@ _sx_xlock_hard(struct sx *sx, uintptr_t tid, int opts, const char *file,
 			    __func__, sx);
 
 #ifdef KDTRACE_HOOKS
-		sleep_time -= lockstat_nsecs();
+		sleep_time -= lockstat_nsecs(&sx->lock_object);
 #endif
 		GIANT_SAVE();
 		sleepq_add(&sx->lock_object, NULL, sx->lock_object.lo_name,
@@ -702,7 +702,7 @@ _sx_xlock_hard(struct sx *sx, uintptr_t tid, int opts, const char *file,
 		else
 			error = sleepq_wait_sig(&sx->lock_object, 0);
 #ifdef KDTRACE_HOOKS
-		sleep_time += lockstat_nsecs();
+		sleep_time += lockstat_nsecs(&sx->lock_object);
 		sleep_cnt++;
 #endif
 		if (error) {
@@ -717,7 +717,7 @@ _sx_xlock_hard(struct sx *sx, uintptr_t tid, int opts, const char *file,
 			    __func__, sx);
 	}
 #ifdef KDTRACE_HOOKS
-	all_time += lockstat_nsecs();
+	all_time += lockstat_nsecs(&sx->lock_object);
 	if (sleep_time)
 		LOCKSTAT_RECORD4(LS_SX_XLOCK_BLOCK, sx, sleep_time,
 		    LOCKSTAT_WRITER, (state & SX_LOCK_SHARED) == 0,
@@ -828,7 +828,7 @@ _sx_slock_hard(struct sx *sx, int opts, const char *file, int line)
 
 #ifdef KDTRACE_HOOKS
 	state = sx->sx_lock;
-	all_time -= lockstat_nsecs();
+	all_time -= lockstat_nsecs(&sx->lock_object);
 #endif
 
 	/*
@@ -955,7 +955,7 @@ _sx_slock_hard(struct sx *sx, int opts, const char *file, int line)
 			    __func__, sx);
 
 #ifdef KDTRACE_HOOKS
-		sleep_time -= lockstat_nsecs();
+		sleep_time -= lockstat_nsecs(&sx->lock_object);
 #endif
 		GIANT_SAVE();
 		sleepq_add(&sx->lock_object, NULL, sx->lock_object.lo_name,
@@ -966,7 +966,7 @@ _sx_slock_hard(struct sx *sx, int opts, const char *file, int line)
 		else
 			error = sleepq_wait_sig(&sx->lock_object, 0);
 #ifdef KDTRACE_HOOKS
-		sleep_time += lockstat_nsecs();
+		sleep_time += lockstat_nsecs(&sx->lock_object);
 		sleep_cnt++;
 #endif
 		if (error) {
@@ -981,7 +981,7 @@ _sx_slock_hard(struct sx *sx, int opts, const char *file, int line)
 			    __func__, sx);
 	}
 #ifdef KDTRACE_HOOKS
-	all_time += lockstat_nsecs();
+	all_time += lockstat_nsecs(&sx->lock_object);
 	if (sleep_time)
 		LOCKSTAT_RECORD4(LS_SX_SLOCK_BLOCK, sx, sleep_time,
 		    LOCKSTAT_READER, (state & SX_LOCK_SHARED) == 0,
diff --git a/sys/sys/lockstat.h b/sys/sys/lockstat.h
index b550e8d..b9a900d 100644
--- a/sys/sys/lockstat.h
+++ b/sys/sys/lockstat.h
@@ -149,11 +149,12 @@
  * The following must match the type definition of dtrace_probe.  It is
  * defined this way to avoid having to rely on CDDL code.
  */
+struct lock_object;
 extern uint32_t lockstat_probemap[LS_NPROBES];
 typedef void (*lockstat_probe_func_t)(uint32_t, uintptr_t arg0, uintptr_t arg1,
     uintptr_t arg2, uintptr_t arg3, uintptr_t arg4);
 extern lockstat_probe_func_t lockstat_probe_func;
-extern uint64_t lockstat_nsecs(void);
+extern uint64_t lockstat_nsecs(struct lock_object *);
 extern int lockstat_enabled;
 
 #ifdef	KDTRACE_HOOKS