Index: sys/amd64/amd64/cpu_switch.S
===================================================================
--- sys/amd64/amd64/cpu_switch.S
+++ sys/amd64/amd64/cpu_switch.S
@@ -138,7 +138,10 @@
 	movq	%rdx,%r15
 	movq	%rsi,%rdi
 	callq	pmap_activate_sw
-	movq	%r15,TD_LOCK(%r13)		/* Release the old thread */
+
+	/* Evict non-temporal stores, and release the old thread. */
+	sfence
+	movq	%r15,TD_LOCK(%r13)
 sw1:
 	movq	TD_PCB(%r12),%r8
 #if defined(SCHED_ULE) && defined(SMP)