Index: alpha/clock.c
===================================================================
RCS file: /cvs/src/sys/arch/alpha/alpha/clock.c,v
retrieving revision 1.21
diff -u -p -r1.21 clock.c
--- alpha/clock.c	23 Mar 2012 15:51:25 -0000	1.21
+++ alpha/clock.c	24 Jun 2015 00:21:51 -0000
@@ -70,6 +70,12 @@ struct timecounter rpcc_timecounter = {
 	rpcc_get_timecount, NULL, ~0u, 0, "rpcc", 0, NULL
 };
 
+unsigned long
+__rpcc_per_second(void)
+{
+	return (rpcc_timecounter.tc_frequency);
+}
+
 void
 clockattach(dev, fns)
 	struct device *dev;
Index: alpha/lock_machdep.c
===================================================================
RCS file: /cvs/src/sys/arch/alpha/alpha/lock_machdep.c,v
retrieving revision 1.3
diff -u -p -r1.3 lock_machdep.c
--- alpha/lock_machdep.c	11 Feb 2015 03:56:00 -0000	1.3
+++ alpha/lock_machdep.c	24 Jun 2015 00:21:51 -0000
@@ -19,6 +19,7 @@
 
 #include <sys/param.h>
 #include <sys/systm.h>
+#include <sys/atomic.h>
 
 #include <machine/atomic.h>
 #include <machine/cpu.h>
@@ -34,29 +35,6 @@
 extern int __mp_lock_spinout;
 #endif
 
-static inline int
-__cpu_cas(volatile unsigned long *addr, unsigned long old, unsigned long new)
-{
-	unsigned long t0, v0;
-
-	__asm volatile(
-		"1:	ldq_l	%1, 0(%2)	\n"	/* v0 = *addr */
-		"	cmpeq	%1, %3, %0	\n"	/* t0 = v0 == old */
-		"	beq	%0, 2f		\n"
-		"	mov	%4, %0		\n"	/* t0 = new */
-		"	stq_c	%0, 0(%2)	\n"	/* *addr = new */
-		"	beq	%0, 3f		\n"
-		"	mb			\n"
-		"2:	br	4f		\n"
-		"3:	br	1b		\n"	/* update failed */
-		"4:				\n"
-		: "=&r" (t0), "=&r" (v0)
-		: "r" (addr), "r" (old), "r" (new)
-		: "memory");
-
-	return (v0 != old);
-}
-
 void
 __mp_lock_init(struct __mp_lock *lock)
 {
@@ -67,22 +45,20 @@ __mp_lock_init(struct __mp_lock *lock)
 static inline void
 __mp_lock_spin(struct __mp_lock *mpl)
 {
-#ifndef MP_LOCKDEBUG
-	while (mpl->mpl_count != 0)
-		SPINLOCK_SPIN_HOOK;
-#else
-	int ticks = __mp_lock_spinout;
-	if (!CPU_IS_PRIMARY(curcpu()))				/* XXX */
-		ticks += ticks;					/* XXX */
+#if defined(MP_LOCKDEBUG)
+	long target = (long)(alpha_rpcc() + __rpcc_per_second() * 8);
+#endif
 
-	while (mpl->mpl_count != 0 && --ticks > 0)
+	while (mpl->mpl_count != 0) {
 		SPINLOCK_SPIN_HOOK;
 
-	if (ticks == 0) {
-		db_printf("__mp_lock(%p): lock spun out", mpl);
-		Debugger();
-	}
+#if defined(MP_LOCKDEBUG)
+		if ((long)alpha_rpcc() - target > 0) {
+			db_printf("%s: %p spun out", __func__, mpl);
+			Debugger();
+		}
 #endif
+	}
 }
 
 void
@@ -104,7 +80,7 @@ __mp_lock(struct __mp_lock *mpl)
 	 */
 	while (1) {
 		s = splhigh();
-		if (__cpu_cas(&mpl->mpl_count, 0, 1) == 0) {
+		if (atomic_cas_ulong(&mpl->mpl_count, 0, 1) == 0) {
 			alpha_mb();
 			mpl->mpl_cpu = ci;
 		}
Index: alpha/mutex.c
===================================================================
RCS file: /cvs/src/sys/arch/alpha/alpha/mutex.c,v
retrieving revision 1.14
diff -u -p -r1.14 mutex.c
--- alpha/mutex.c	17 Apr 2015 12:38:54 -0000	1.14
+++ alpha/mutex.c	24 Jun 2015 00:21:51 -0000
@@ -47,8 +47,20 @@ __mtx_init(struct mutex *mtx, int wantip
 void
 mtx_enter(struct mutex *mtx)
 {
-	while (mtx_enter_try(mtx) == 0)
+#if defined(MP_LOCKDEBUG)
+	long target = (long)(alpha_rpcc() + __rpcc_per_second() * 8);
+#endif
+
+	while (mtx_enter_try(mtx) == 0) {
 		SPINLOCK_SPIN_HOOK;
+
+#if defined(MP_LOCKDEBUG)
+		if ((long)alpha_rpcc() - target > 0) {
+			db_printf("%s: %p spun out", __func__, mtx);
+			Debugger();
+		}
+#endif
+	}
 }
 
 int
Index: include/lock.h
===================================================================
RCS file: /cvs/src/sys/arch/alpha/include/lock.h,v
retrieving revision 1.9
diff -u -p -r1.9 lock.h
--- include/lock.h	11 Feb 2015 03:56:00 -0000	1.9
+++ include/lock.h	24 Jun 2015 00:21:51 -0000
@@ -59,6 +59,9 @@ do {									\
 		splx(__s);						\
 	}								\
 } while (0)
+
+unsigned long __rpcc_per_second(void);
+
 #endif /* MULTIPROCESSOR */
 
 #endif /* _MACHINE_LOCK_H_ */