Index: subr_taskqueue.c
===================================================================
RCS file: /usr/ncvs/src/sys/kern/subr_taskqueue.c,v
retrieving revision 1.26
diff -u -r1.26 subr_taskqueue.c
--- subr_taskqueue.c	24 Apr 2005 16:52:45 -0000	1.26
+++ subr_taskqueue.c	25 Apr 2005 15:58:28 -0000
@@ -25,7 +25,7 @@
  */
 
 #include <sys/cdefs.h>
-__FBSDID("$FreeBSD: src/sys/kern/subr_taskqueue.c,v 1.26 2005/04/24 16:52:45 sam Exp $");
+__FBSDID("$FreeBSD: src/sys/kern/subr_taskqueue.c,v 1.25 2004/10/05 04:16:00 imp Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -56,6 +56,9 @@
 };
 
 static void	init_taskqueue_list(void *data);
+#ifdef DIAGNOSTIC
+struct mtx dont_sleep_in_taskqueue;
+#endif
 
 static void
 init_taskqueue_list(void *data __unused)
@@ -63,6 +66,10 @@
 
 	mtx_init(&taskqueue_queues_mutex, "taskqueue list", NULL, MTX_DEF);
 	STAILQ_INIT(&taskqueue_queues);
+#ifdef DIAGNOSTIC
+	mtx_init(&dont_sleep_in_taskqueue, "dont_sleep_in_taskqueue",
+		NULL, MTX_DEF);
+#endif
 }
 SYSINIT(taskqueue_list, SI_SUB_INTRINSIC, SI_ORDER_ANY, init_taskqueue_list,
     NULL);
@@ -174,6 +181,14 @@
 {
 	struct task *task;
 	int owned, pending;
+#ifdef DIAGNOSTIC
+	struct bintime bt1, bt2;
+	struct timespec ts2;
+	static uint64_t maxdt = 36893488147419102LL;	/* 2 msec */
+	static task_fn_t *lastfunc;
+	task_fn_t *t_func;
+	void *t_arg;
+#endif
 
 	owned = mtx_owned(&queue->tq_mutex);
 	if (!owned)
@@ -189,9 +204,34 @@
 		task->ta_pending = 0;
 		queue->tq_running = task;
 		mtx_unlock(&queue->tq_mutex);
+#ifdef DIAGNOSTIC
+		binuptime(&bt1);
+		mtx_lock(&dont_sleep_in_taskqueue);
+		t_func = task->ta_func;
+		t_arg = task->ta_context;
+#endif
 
 		task->ta_func(task->ta_context, pending);
 
+#ifdef DIAGNOSTIC
+		mtx_unlock(&dont_sleep_in_taskqueue);
+		binuptime(&bt2);
+		bintime_sub(&bt2, &bt1);
+		if (bt2.frac > maxdt) {
+			if (lastfunc != t_func ||
+			    bt2.frac > maxdt * 2) {
+				bintime2timespec(&bt2, &ts2);
+				printf("Expensive taskqueue(9) function: "
+				    "%p(%p) %jd.%09ld s\n",
+				    t_func, t_arg,
+				    (intmax_t)ts2.tv_sec,
+				    ts2.tv_nsec);
+			}
+			maxdt = bt2.frac;
+			lastfunc = t_func;
+		}
+#endif
+
 		mtx_lock(&queue->tq_mutex);
 		queue->tq_running = NULL;
 		wakeup(task);