--- //depot/user/jhb/intr/amd64/amd64/intr_machdep.c
+++ /home/jhb/work/p4/intr/amd64/amd64/intr_machdep.c
@@ -476,6 +476,23 @@
 	return (intr_event_bind(isrc->is_event, cpu));
 }
 
+/* Tag an active interrupt handler. */
+int
+intr_tag(u_int vector, void *ih, const char *tag)
+{
+	struct intsrc *isrc;
+	int error;
+
+	isrc = intr_lookup_source(vector);
+	if (isrc == NULL)
+		return (EINVAL);
+	error = intr_event_tag_handler(isrc->is_event, ih, tag);
+	if (error)
+		return (error);
+	intrcnt_updatename(isrc);
+	return (0);
+}
+
 /*
  * Add a CPU to our mask of valid CPUs that can be destinations of
  * interrupts.
--- //depot/user/jhb/intr/amd64/amd64/nexus.c
+++ /home/jhb/work/p4/intr/amd64/amd64/nexus.c
@@ -101,6 +101,8 @@
 static	int nexus_setup_intr(device_t, device_t, struct resource *, int flags,
 			     driver_filter_t filter, void (*)(void *), void *, 
 			     void **);
+static	int nexus_tag_intr(device_t dev, device_t child, struct resource *irq,
+			   void *cookie, const char *tag);
 static	int nexus_teardown_intr(device_t, device_t, struct resource *,
 				void *);
 static struct resource_list *nexus_get_reslist(device_t dev, device_t child);
@@ -135,6 +137,7 @@
 	DEVMETHOD(bus_bind_intr,	nexus_bind_intr),
 #endif
 	DEVMETHOD(bus_config_intr,	nexus_config_intr),
+	DEVMETHOD(bus_tag_intr,		nexus_tag_intr),
 	DEVMETHOD(bus_get_resource_list, nexus_get_reslist),
 	DEVMETHOD(bus_set_resource,	nexus_set_resource),
 	DEVMETHOD(bus_get_resource,	nexus_get_resource),
@@ -479,6 +482,14 @@
 	return (intr_config_intr(irq, trig, pol));
 }
 
+static int
+nexus_tag_intr(device_t dev, device_t child, struct resource *irq,
+    void *cookie, const char *tag)
+{
+
+	return (intr_tag(rman_get_start(irq), cookie, tag));
+}
+
 static struct resource_list *
 nexus_get_reslist(device_t dev, device_t child)
 {
--- //depot/user/jhb/intr/amd64/include/intr_machdep.h
+++ /home/jhb/work/p4/intr/amd64/include/intr_machdep.h
@@ -160,6 +160,7 @@
 int	intr_remove_handler(void *cookie);
 void	intr_resume(void);
 void	intr_suspend(void);
+int	intr_tag(u_int vector, void *ih, const char *tag);
 void	intrcnt_add(const char *name, u_long **countp);
 void	nexus_add_irq(u_long irq);
 int	msi_alloc(device_t dev, int count, int maxcount, int *irqs);
--- //depot/user/jhb/intr/dev/e1000/if_igb.c
+++ /home/jhb/work/p4/intr/dev/e1000/if_igb.c
@@ -2160,6 +2160,7 @@
 	struct tx_ring *txr = adapter->tx_rings;
 	struct rx_ring *rxr = adapter->rx_rings;
 	int error, rid, vector = 0;
+	char buf[MAXCOMLEN];
 
 	/*
 	 * Setup the interrupt handlers
@@ -2181,9 +2182,13 @@
 		    igb_msix_tx, txr, &txr->tag);
 		if (error) {
 			txr->res = NULL;
-			device_printf(dev, "Failed to register TX handler");
+			device_printf(dev, "Failed to register TX handler\n");
 			return (error);
 		}
+		snprintf(buf, sizeof(buf), "tx %d", i);
+		error = bus_tag_intr(dev, txr->res, txr->tag, buf);
+		if (error)
+			device_printf(dev, "Failed to tag TX handler\n");
 		/* Make tasklet for deferred handling - one per queue */
 		TASK_INIT(&txr->tx_task, 0, igb_handle_tx, txr);
 		txr->msix = vector;
@@ -2215,9 +2220,13 @@
 		    igb_msix_rx, rxr, &rxr->tag);
 		if (error) {
 			rxr->res = NULL;
-			device_printf(dev, "Failed to register RX handler");
+			device_printf(dev, "Failed to register RX handler\n");
 			return (error);
 		}
+		snprintf(buf, sizeof(buf), "rx %d", i);
+		error = bus_tag_intr(dev, rxr->res, rxr->tag, buf);
+		if (error)
+			device_printf(dev, "Failed to tag RX handler\n");
 		/* Make tasklet for deferred handling - one per queue */
 		TASK_INIT(&rxr->rx_task, 0, igb_handle_rx, rxr);
 		rxr->msix = vector;
@@ -2251,9 +2260,12 @@
 	if ((error = bus_setup_intr(dev, adapter->res,
 	    INTR_TYPE_NET | INTR_MPSAFE, NULL,
 	    igb_msix_link, adapter, &adapter->tag)) != 0) {
-		device_printf(dev, "Failed to register Link handler");
+		device_printf(dev, "Failed to register Link handler\n");
 		return (error);
 	}
+	error = bus_tag_intr(dev, adapter->res, adapter->tag, "link");
+	if (error)
+		device_printf(dev, "Failed to tag link handler\n");
 	adapter->linkvec = vector;
 	adapter->tq = taskqueue_create_fast("igb_taskq", M_NOWAIT,
 	    taskqueue_thread_enqueue, &adapter->tq);
--- //depot/user/jhb/intr/kern/bus_if.m
+++ /home/jhb/work/p4/intr/kern/bus_if.m
@@ -509,6 +509,23 @@
 	int		_cpu;
 } DEFAULT bus_generic_bind_intr;
 
+/**
+ * @brief Allow drivers to associate a tag with an active interrupt handler.
+ *
+ * @param _dev		the parent device of @p _child
+ * @param _child	the device which allocated the resource
+ * @param _irq		the resource representing the interrupt
+ * @param _cookie	the cookie value returned when the interrupt
+ *			was originally registered
+ * @param _tag		the tag string to associate with the interrupt
+ */
+METHOD int tag_intr {
+	device_t	_dev;
+	device_t	_child;
+	struct resource *_irq;
+	void		*_cookie;
+	const char	*_tag;
+} DEFAULT bus_generic_tag_intr;
 
 /**
  * @brief Allow (bus) drivers to specify the trigger mode and polarity
--- //depot/user/jhb/intr/kern/kern_intr.c
+++ /home/jhb/work/p4/intr/kern/kern_intr.c
@@ -524,7 +524,7 @@
 	ih->ih_filter = filter;
 	ih->ih_handler = handler;
 	ih->ih_argument = arg;
-	ih->ih_name = name;
+	strncpy(ih->ih_name, name, sizeof(ih->ih_name - 1));
 	ih->ih_event = ie;
 	ih->ih_pri = pri;
 	if (flags & INTR_EXCL)
@@ -597,7 +597,7 @@
 	ih->ih_filter = filter;
 	ih->ih_handler = handler;
 	ih->ih_argument = arg;
-	ih->ih_name = name;
+	strncpy(ih->ih_name, name, sizeof(ih->ih_name - 1));
 	ih->ih_event = ie;
 	ih->ih_pri = pri;
 	if (flags & INTR_EXCL)
@@ -665,6 +665,60 @@
 #endif
 
 /*
+ * Append a tag preceded by a ':' to the name of the specified
+ * interrupt handler.
+ */
+int
+intr_event_tag_handler(struct intr_event *ie, void *cookie, const char *tag)
+{
+	struct intr_handler *ih;
+	size_t space;
+	char *start;
+
+	mtx_lock(&ie->ie_lock);
+#ifdef INVARIANTS
+	TAILQ_FOREACH(ih, &ie->ie_handlers, ih_next) {
+		if (ih == cookie)
+			break;
+	}
+	if (ih == NULL) {
+		mtx_unlock(&ie->ie_lock);
+		panic("handler %p not find in interrupt event %p", cookie, ie);
+	}
+#endif
+	ih = cookie;
+
+	/*
+	 * Look for an existing tag by checking for an existing ":".
+	 * This assumes device names do not include colons.  If one is
+	 * found, prepare to insert the new tag at that point.  If one
+	 * is not found, find the end of the name to use as the
+	 * insertion point.
+	 */
+	start = index(ih->ih_name, ':');
+	if (start == NULL)
+		start = index(ih->ih_name, 0);
+
+	/*
+	 * See if there is enough remaining room in the string for the
+	 * tag + ":".  The "- 1" leaves room for the trailing '\0'.
+	 * The "+ 1" accounts for the colon.
+	 */
+	space = sizeof(ih->ih_name) - (start - ih->ih_name) - 1;
+	if (strlen(tag) + 1 > space) {
+		mtx_unlock(&ie->ie_lock);
+		return (ENOSPC);
+	}
+
+	/* Append a colon followed by the tag. */
+	*start = ':';
+	strcpy(start + 1, tag);
+	intr_event_update(ie);
+	mtx_unlock(&ie->ie_lock);
+	return (0);
+}
+
+/*
  * Return the ie_source field from the intr_event an intr_handler is
  * associated with.
  */
--- //depot/user/jhb/intr/kern/subr_bus.c
+++ /home/jhb/work/p4/intr/kern/subr_bus.c
@@ -3519,6 +3519,23 @@
 }
 
 /**
+ * @brief Helper function for implementing BUS_TAG_INTR().
+ *
+ * This simple implementation of BUS_TAG_INTR() simply calls the
+ * BUS_TAG_INTR() method of the parent of @p dev.
+ */
+int
+bus_generic_tag_intr(device_t dev, device_t child, struct resource *irq,
+    void *cookie, const char *tag)
+{
+
+	/* Propagate up the bus hierarchy until someone handles it. */
+	if (dev->parent)
+		return (BUS_TAG_INTR(dev->parent, child, irq, cookie, tag));
+	return (EINVAL);
+}
+
+/**
  * @brief Helper function for implementing BUS_CONFIG_INTR().
  *
  * This simple implementation of BUS_CONFIG_INTR() simply calls the
@@ -3840,6 +3857,20 @@
 }
 
 /**
+ * @brief Wrapper function for BUS_TAG_INTR().
+ *
+ * This function simply calls the BUS_TAG_INTR() method of the parent
+ * of @p dev.
+ */
+int
+bus_tag_intr(device_t dev, struct resource *irq, void *cookie, const char *tag)
+{
+	if (dev->parent == NULL)
+		return (EINVAL);
+	return (BUS_TAG_INTR(dev->parent, dev, irq, cookie, tag));
+}
+
+/**
  * @brief Wrapper function for BUS_SET_RESOURCE().
  *
  * This function simply calls the BUS_SET_RESOURCE() method of the
--- //depot/user/jhb/intr/sys/bus.h
+++ /home/jhb/work/p4/intr/sys/bus.h
@@ -331,6 +331,8 @@
 
 int	bus_generic_shutdown(device_t dev);
 int	bus_generic_suspend(device_t dev);
+int	bus_generic_tag_intr(device_t dev, device_t child, struct resource *irq,
+			     void *cookie, const char *tag);
 int	bus_generic_teardown_intr(device_t dev, device_t child,
 				  struct resource *irq, void *cookie);
 int	bus_generic_write_ivar(device_t dev, device_t child, int which,
@@ -347,8 +349,10 @@
 	int	flags;
 };
 
-int bus_alloc_resources(device_t dev, struct resource_spec *rs, struct resource **res);
-void bus_release_resources(device_t dev, const struct resource_spec *rs, struct resource **res);
+int	bus_alloc_resources(device_t dev, struct resource_spec *rs,
+			    struct resource **res);
+void	bus_release_resources(device_t dev, const struct resource_spec *rs,
+			      struct resource **res);
 
 struct	resource *bus_alloc_resource(device_t dev, int type, int *rid,
 				     u_long start, u_long end, u_long count,
@@ -364,6 +368,8 @@
 int	bus_setup_intr(device_t dev, struct resource *r, int flags,
 		       driver_filter_t filter, driver_intr_t handler, 
 		       void *arg, void **cookiep);
+int	bus_tag_intr(device_t dev, struct resource *irq, void *cookie,
+		     const char *tag);
 int	bus_teardown_intr(device_t dev, struct resource *r, void *cookie);
 int	bus_bind_intr(device_t dev, struct resource *r, int cpu);
 int	bus_set_resource(device_t dev, int type, int rid,
--- //depot/user/jhb/intr/sys/interrupt.h
+++ /home/jhb/work/p4/intr/sys/interrupt.h
@@ -47,7 +47,7 @@
 	driver_intr_t	*ih_handler;	/* Threaded handler function. */
 	void		*ih_argument;	/* Argument to pass to handlers. */
 	int		 ih_flags;
-	const char	*ih_name;	/* Name of handler. */
+	char		 ih_name[MAXCOMLEN]; /* Name of handler. */
 	struct intr_event *ih_event;	/* Event we are connected to. */
 	int		 ih_need;	/* Needs service. */
 	TAILQ_ENTRY(intr_handler) ih_next; /* Next handler for this event. */
@@ -172,6 +172,8 @@
 void	intr_event_execute_handlers(struct proc *p, struct intr_event *ie);
 int	intr_event_handle(struct intr_event *ie, struct trapframe *frame);
 int	intr_event_remove_handler(void *cookie);
+int	intr_event_tag_handler(struct intr_event *ie, void *cookie,
+	    const char *tag);
 int	intr_getaffinity(int irq, void *mask);
 void	*intr_handler_source(void *cookie);
 int	intr_setaffinity(int irq, void *mask);