time-bind and lower power in lock spinning and a couple of other ipi loops by using pause insn; brad@ ok tedu@ ok and feedback krw@ testing

4 files changed, 25 insertions, 27 deletions

diff --git a/sys/arch/i386/i386/lapic.c b/sys/arch/i386/i386/lapic.c
index 4053df12805..77bb270c8b6 100644
--- a/sys/arch/i386/i386/lapic.c
+++ b/sys/arch/i386/i386/lapic.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: lapic.c,v 1.6 2006/03/10 21:09:22 mickey Exp $	*/
+/*	$OpenBSD: lapic.c,v 1.7 2006/03/13 18:42:16 mickey Exp $	*/
 /* $NetBSD: lapic.c,v 1.1.2.8 2000/02/23 06:10:50 sommerfeld Exp $ */
 
 /*-
@@ -441,25 +441,28 @@ i386_ipi_init(target)
 {
 	unsigned j;
 
-	if ((target & LAPIC_DEST_MASK) == 0) {
+	if ((target & LAPIC_DEST_MASK) == 0)
 		i82489_writereg(LAPIC_ICRHI, target << LAPIC_ID_SHIFT);
-	}
 
 	i82489_writereg(LAPIC_ICRLO, (target & LAPIC_DEST_MASK) |
 	    LAPIC_DLMODE_INIT | LAPIC_LVL_ASSERT );
 
-	for (j = 100000; j > 0; j--)
+	for (j = 100000; j > 0; j--) {
+		__asm __volatile("pause": : :"memory");
 		if ((i82489_readreg(LAPIC_ICRLO) & LAPIC_DLSTAT_BUSY) == 0)
 			break;
+	}
 
 	delay(10000);
 
 	i82489_writereg(LAPIC_ICRLO, (target & LAPIC_DEST_MASK) |
 	     LAPIC_DLMODE_INIT | LAPIC_LVL_TRIG | LAPIC_LVL_DEASSERT);
 
-	for (j = 100000; j > 0; j--)
+	for (j = 100000; j > 0; j--) {
+		__asm __volatile("pause": : :"memory");
 		if ((i82489_readreg(LAPIC_ICRLO) & LAPIC_DLSTAT_BUSY) == 0)
 			break;
+	}
 
 	return (i82489_readreg(LAPIC_ICRLO) & LAPIC_DLSTAT_BUSY)?EBUSY:0;
 }
@@ -479,7 +482,7 @@ i386_ipi(vec,target,dl)
 	for (j = 100000;
 	     j > 0 && (i82489_readreg(LAPIC_ICRLO) & LAPIC_DLSTAT_BUSY);
 	     j--)
-		;
+		SPINLOCK_SPIN_HOOK;
 
 	return (i82489_readreg(LAPIC_ICRLO) & LAPIC_DLSTAT_BUSY) ? EBUSY : 0;
 }
diff --git a/sys/arch/i386/i386/pmap.c b/sys/arch/i386/i386/pmap.c
index 425926da4d5..765b2b9d233 100644
--- a/sys/arch/i386/i386/pmap.c
+++ b/sys/arch/i386/i386/pmap.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: pmap.c,v 1.90 2006/03/12 21:28:54 tom Exp $	*/
+/*	$OpenBSD: pmap.c,v 1.91 2006/03/13 18:42:16 mickey Exp $	*/
 /*	$NetBSD: pmap.c,v 1.91 2000/06/02 17:46:37 thorpej Exp $	*/
 
 /*
@@ -3595,15 +3595,14 @@ pmap_tlb_shootnow(int32_t cpumask)
 				    (1U << ci->ci_cpuid));
 	}
 
-	while (self->ci_tlb_ipi_mask != 0)
+	while (self->ci_tlb_ipi_mask != 0) {
+		SPINLOCK_SPIN_HOOK;
 #ifdef DIAGNOSTIC
 		if (count++ > 100000000)
 			panic("%s: TLB IPI rendezvous failed (mask 0x%x)",
 			    self->ci_dev.dv_xname, self->ci_tlb_ipi_mask);
-#else
-		/* XXX insert pause instruction */
-		;
 #endif
+	}
 #endif
 }
 
diff --git a/sys/arch/i386/include/lock.h b/sys/arch/i386/include/lock.h
index a647999a532..fe0578a3139 100644
--- a/sys/arch/i386/include/lock.h
+++ b/sys/arch/i386/include/lock.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: lock.h,v 1.2 2004/06/13 21:49:16 niklas Exp $	*/
+/*	$OpenBSD: lock.h,v 1.3 2006/03/13 18:42:16 mickey Exp $	*/
 /*	$NetBSD: lock.h,v 1.1.2.2 2000/05/03 14:40:55 sommerfeld Exp $	*/
 
 /*-
@@ -59,6 +59,8 @@ typedef	__volatile int		__cpu_simple_lock_t;
 
 #define __lockbarrier() __asm __volatile("": : :"memory")
 
+#define SPINLOCK_SPIN_HOOK	__asm __volatile("pause": : :"memory")
+
 #ifdef LOCKDEBUG
 
 extern void __cpu_simple_lock_init(__cpu_simple_lock_t *);
@@ -90,9 +92,8 @@ static __inline void
 __cpu_simple_lock(__cpu_simple_lock_t *lockp)
 {
 	while (i386_atomic_testset_i(lockp, __SIMPLELOCK_LOCKED)
-	    == __SIMPLELOCK_LOCKED) {
-		continue;	/* spin */
-	}
+	    == __SIMPLELOCK_LOCKED)
+		SPINLOCK_SPIN_HOOK;
 	__lockbarrier();
 }
 
diff --git a/sys/arch/i386/isa/npx.c b/sys/arch/i386/isa/npx.c
index 9b26e2ba4af..3fd0102dcbf 100644
--- a/sys/arch/i386/isa/npx.c
+++ b/sys/arch/i386/isa/npx.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: npx.c,v 1.37 2005/06/06 14:25:20 mickey Exp $	*/
+/*	$OpenBSD: npx.c,v 1.38 2006/03/13 18:42:16 mickey Exp $	*/
 /*	$NetBSD: npx.c,v 1.57 1996/05/12 23:12:24 mycroft Exp $	*/
 
 #if 0
@@ -823,22 +823,17 @@ npxsave_proc(struct proc *p, int save)
 #ifdef DIAGNOSTIC
 		spincount = 0;
 #endif
-		while (p->p_addr->u_pcb.pcb_fpcpu != NULL)
+		while (p->p_addr->u_pcb.pcb_fpcpu != NULL) {
+			SPINLOCK_SPIN_HOOK;
 #ifdef DIAGNOSTIC
-		{
-			spincount++;
-			if (spincount > 100000000) {
-				panic("fp_save ipi didn't");
-			}
-		}
-#else
-		__splbarrier();		/* XXX replace by generic barrier */
-		;
+			if (spincount++ > 100000000)
+				panic("%s: fp_save ipi didn't (%s)",
+				    ci->ci_dev.dv_xname, oci->ci_dev.dv_xname);
 #endif
+		}
 	}
 #else
 	KASSERT(ci->ci_fpcurproc == p);
 	npxsave_cpu(ci, save);
 #endif
 }
-