diff --git a/sys/kern/kern_intr.c b/sys/kern/kern_intr.c
--- a/sys/kern/kern_intr.c
+++ b/sys/kern/kern_intr.c
@@ -3,6 +3,7 @@
  *
  * Copyright (c) 1997, Stefan Esser <se@freebsd.org>
  * All rights reserved.
+ * Copyright © 2022-2023 Elliott Mitchell
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -286,10 +287,11 @@
 	struct intr_event *ie;
 	va_list ap;
 
-	/* The only valid flag during creation is IE_SOFT. */
-	if ((flags & ~IE_SOFT) != 0)
+	/* The flags valid during creation are IE_SOFT and IE_MULTIPROC. */
+	if ((flags & ~(IE_SOFT | IE_MULTIPROC)) != 0)
 		return (EINVAL);
-	ie = malloc(sizeof(struct intr_event), M_ITHREAD, M_WAITOK | M_ZERO);
+	ie = malloc(sizeof(struct intr_event) + (flags & IE_MULTIPROC ?
+	    sizeof(u_long) * (mp_ncpus - 1) : 0), M_ITHREAD, M_WAITOK | M_ZERO);
 	ie->ie_source = source;
 	ie->ie_pre_ithread = pre_ithread;
 	ie->ie_post_ithread = post_ithread;
@@ -298,6 +300,7 @@
 	ie->ie_flags = flags;
 	ie->ie_irq = irq;
 	ie->ie_cpu = NOCPU;
+	/* ->ie_stray and ->ie_intrcnt[] handled by M_ZERO */
 	CK_SLIST_INIT(&ie->ie_handlers);
 	mtx_init(&ie->ie_lock, "intr event", NULL, MTX_DEF);
 
@@ -1370,10 +1373,30 @@
 	intr_prof_stack_use(td, frame);
 #endif
 
-	/* An interrupt with no event or handlers is a stray interrupt. */
-	if (ie == NULL || CK_SLIST_EMPTY(&ie->ie_handlers))
+	/* An interrupt with no event is a stray interrupt. */
+	if (ie == NULL)
 		return (EINVAL);
 
+	/*
+	 * Note about interrupt counters.  Having per-processor counters avoids
+	 * the need for atomic increment of counters.  Whereas other interrupt
+	 * types will be bound to a single processor and not need atomics.
+	 * Per-processor interrupts are *never* flagged as stray, so stray
+	 * counters don't need atomic increment.
+	 */
+
+	/* Increment the interrupt counter. */
+	if (__predict_false(ie->ie_flags & IE_MULTIPROC))
+		++ie->ie_intrcnt[curcpu];
+	else
+		++ie->ie_intrcnt[0];
+
+	/* An interrupt with no handlers is a stray interrupt. */
+	if (CK_SLIST_EMPTY(&ie->ie_handlers)) {
+		++ie->ie_stray;
+		return (EINVAL);
+	}
+
 	/*
 	 * Execute fast interrupt handlers directly.
 	 * To support clock handlers, if a handler registers
@@ -1473,8 +1496,10 @@
 	td->td_intr_nesting_level--;
 #ifdef notyet
 	/* The interrupt is not aknowledged by any filter and has no ithread. */
-	if (!thread && !filter)
+	if (!thread && !filter) {
+		++ie->ie_stray;
 		return (EINVAL);
+	}
 #endif
 	return (0);
 }
@@ -1625,9 +1650,12 @@
 start_softintr(void *dummy)
 {
 
-	if (swi_add(&clk_intr_event, "clk", NULL, NULL, SWI_CLOCK,
-	    INTR_MPSAFE, NULL))
-		panic("died while creating clk swi ithread");
+	KASSERT(clk_intr_event == NULL, ("clk_intr_event non-NULL at %s()",
+	    __func__));
+
+	if (intr_event_create(&clk_intr_event, NULL, IE_SOFT | IE_MULTIPROC,
+	    0, NULL, NULL, NULL, swi_assign_cpu, "clk swi%d:", SWI_CLOCK))
+		panic("died while creating clk swi event");
 }
 SYSINIT(start_softintr, SI_SUB_SOFTINTR, SI_ORDER_FIRST, start_softintr,
     NULL);
diff --git a/sys/kern/subr_intr.c b/sys/kern/subr_intr.c
--- a/sys/kern/subr_intr.c
+++ b/sys/kern/subr_intr.c
@@ -2,7 +2,7 @@
  * Copyright (c) 2015-2016 Svatopluk Kraus
  * Copyright (c) 2015-2016 Michal Meloun
  * All rights reserved.
- * Copyright © 2022 Elliott Mitchell
+ * Copyright © 2022-2023 Elliott Mitchell
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -625,12 +625,15 @@
 isrc_event_create(struct intr_irqsrc *isrc)
 {
 	struct intr_event *ie;
+	u_int flags = 0;
 	int error;
 
 	if (isrc->isrc_event != NULL)
 		return (0);
 
-	error = intr_event_create(&ie, isrc, 0, isrc->isrc_irq,
+	if (isrc->isrc_flags & (INTR_ISRCF_IPI|INTR_ISRCF_PPI))
+		flags |= IE_MULTIPROC;
+	error = intr_event_create(&ie, isrc, flags, isrc->isrc_irq,
 	    intr_isrc_pre_ithread, intr_isrc_post_ithread, intr_isrc_post_filter,
 	    intr_isrc_assign_cpu, "%s:", isrc->isrc_name);
 	if (error)
diff --git a/sys/sys/interrupt.h b/sys/sys/interrupt.h
--- a/sys/sys/interrupt.h
+++ b/sys/sys/interrupt.h
@@ -127,11 +127,14 @@
 	int		ie_cpu;		/* CPU this event is bound to. */
 	volatile int	ie_phase;	/* Switched to establish a barrier. */
 	volatile int	ie_active[2];	/* Filters in ISR context. */
+	u_long		ie_stray;	/* Stray interrupt counter */
+	u_long		ie_intrcnt[1];	/* Interrupt counter(s) */
 };
 
 /* Interrupt event flags kept in ie_flags. */
 #define	IE_SOFT		0x000001	/* Software interrupt. */
 #define	IE_ADDING_THREAD 0x000004	/* Currently building an ithread. */
+#define	IE_MULTIPROC	0x000008	/* Interrupt occurs on multiple procs */
 
 /* Flags to pass to swi_sched. */
 #define	SWI_FROMNMI	0x1