diff --git a/sched/irq/irq.h b/sched/irq/irq.h
index 5df258366f3..124f26bf3ba 100644
--- a/sched/irq/irq.h
+++ b/sched/irq/irq.h
@@ -82,6 +82,9 @@ struct irq_info_s
   uint32_t mscount;  /* Number of interrupts on this IRQ (MS) */
   uint32_t lscount;  /* Number of interrupts on this IRQ (LS) */
 #endif
+#ifdef CONFIG_SCHED_TICKLESS
+  uint32_t time;     /* Maximum execution time on this IRQ */
+#endif
 #endif
 };
 
diff --git a/sched/irq/irq_dispatch.c b/sched/irq/irq_dispatch.c
index 7cf810f6a66..edda4849cc2 100644
--- a/sched/irq/irq_dispatch.c
+++ b/sched/irq/irq_dispatch.c
@@ -45,11 +45,14 @@
 #include <nuttx/random.h>
 
 #include "irq/irq.h"
+#include "clock/clock.h"
 
 /****************************************************************************
  * Pre-processor Definitions
  ****************************************************************************/
 
+/* INCR_COUNT - Increment the count of interrupts taken on this IRQ number */
+
 #ifdef CONFIG_SCHED_IRQMONITOR
 #  ifdef CONFIG_HAVE_LONG_LONG
 #    define INCR_COUNT(ndx) \
@@ -73,6 +76,32 @@
 #  define INCR_COUNT(ndx)
 #endif
 
+/* CALL_VECTOR - Call the interrupt service routine attached to this interrupt
+ * request
+ */
+
+#if defined(CONFIG_SCHED_IRQMONITOR) && defined(CONFIG_SCHED_TICKLESS)
+#  define CALL_VECTOR(ndx, vector, irq, context, arg) \
+     do \
+       { \
+         struct timespec start; \
+         struct timespec end; \
+         struct timespec delta; \
+         clock_systimespec(&start); \
+         vector(irq, context, arg); \
+         clock_systimespec(&end); \
+         clock_timespec_subtract(&end, &start, &delta); \
+         if (delta.tv_nsec > g_irqvector[ndx].time) \
+           { \
+             g_irqvector[ndx].time = delta.tv_nsec; \
+           } \
+       } \
+     while (0)
+#else
+#  define CALL_VECTOR(ndx, vector, irq, context, arg) \
+     vector(irq, context, arg)
+#endif
+
 /****************************************************************************
  * Public Functions
  ****************************************************************************/
@@ -127,5 +156,5 @@ void irq_dispatch(int irq, FAR void *context)
 
   /* Then dispatch to the interrupt handler */
 
-  vector(irq, context, arg);
+  CALL_VECTOR(ndx, vector, irq, context, arg);
 }
diff --git a/sched/irq/irq_initialize.c b/sched/irq/irq_initialize.c
index ef3f60554a8..c02467299ce 100644
--- a/sched/irq/irq_initialize.c
+++ b/sched/irq/irq_initialize.c
@@ -97,6 +97,9 @@ void irq_initialize(void)
       g_irqvector[i].mscount = 0;
       g_irqvector[i].lscount = 0;
 #endif
+#ifdef CONFIG_SCHED_TICKLESS
+      g_irqvector[i].time    = 0;
+#endif
 #endif
     }
 
diff --git a/sched/irq/irq_procfs.c b/sched/irq/irq_procfs.c
index c4cdcb4c9f4..d890a2d1d26 100644
--- a/sched/irq/irq_procfs.c
+++ b/sched/irq/irq_procfs.c
@@ -60,26 +60,45 @@
  ****************************************************************************/
 /* Output format:
  *
- *          11111111112222222222333333333344
- * 12345678901234567890123456789012345678901
+ * In Tickless mode (where IRQ timing is available):
  *
- * IRQ HANDLER  ARGUMENT    COUNT    RATE
- * DDD XXXXXXXX XXXXXXXX DDDDDDDDDD DDDD.DDD
+ *            1111111111222222222233333333334444444444
+ *   1234567890123456789012345678901234567890123456789
+ *
+ *   IRQ HANDLER  ARGUMENT    COUNT    RATE    TIME
+ *   DDD XXXXXXXX XXXXXXXX DDDDDDDDDD DDDD.DDD DDDD
+ *
+ * In other modes:
+ *
+ *            11111111112222222222333333333344
+ *   12345678901234567890123456789012345678901
+ *
+ *   IRQ HANDLER  ARGUMENT    COUNT    RATE
+ *   DDD XXXXXXXX XXXXXXXX DDDDDDDDDD DDDD.DDD
  *
  * NOTE:  This assumes that an address can be represented in 32-bits.  In
  * the typical configuration where CONFIG_HAVE_LONG_LONG=y, the COUNT field
  * may not be wide enough.
  */
 
-#define HDR_FMT "IRQ HANDLER  ARGUMENT    COUNT    RATE\n"
-#define IRQ_FMT "%3u %08lx %08lx %10lu %4lu.%03lu\n"
+#ifdef CONFIG_SCHED_TICKLESS
+#  define HDR_FMT "IRQ HANDLER  ARGUMENT    COUNT    RATE    TIME\n"
+#  define IRQ_FMT "%3u %08lx %08lx %10lu %4lu.%03lu %4lu\n"
+#else
+#  define HDR_FMT "IRQ HANDLER  ARGUMENT    COUNT    RATE\n"
+#  define IRQ_FMT "%3u %08lx %08lx %10lu %4lu.%03lu\n"
+#endif
 
 /* Determines the size of an intermediate buffer that must be large enough
  * to handle the longest line generated by this logic (plus a couple of
  * bytes).
  */
 
-#define IRQ_LINELEN 44
+#ifdef CONFIG_SCHED_TICKLESS
+#  define IRQ_LINELEN 50
+#else
+#  define IRQ_LINELEN 44
+#endif
 
 /****************************************************************************
  * Private Types
@@ -178,6 +197,9 @@ static int irq_callback(int irq, FAR struct irq_info_s *info,
 #else
   info->mscount = 0;
   info->lscount = 0;
+#endif
+#ifdef CONFIG_SCHED_TICKLESS
+  info->time    = 0;
 #endif
   leave_critical_section(flags);
 
@@ -251,7 +273,11 @@ static int irq_callback(int irq, FAR struct irq_info_s *info,
                       (unsigned int)irq,
                       (unsigned long)((uintptr_t)copy.handler),
                       (unsigned long)((uintptr_t)copy.arg),
+#ifdef CONFIG_SCHED_TICKLESS
+                      count, intpart, fracpart, copy.time / 1000);
+#else
                       count, intpart, fracpart);
+#endif
 
   copysize  = procfs_memcpy(irqfile->line, linesize, irqfile->buffer,
                             irqfile->remaining, &irqfile->offset);