diff --git a/lib/thread.c b/lib/thread.c
index 9c3ee82..cb51332 100644
--- a/lib/thread.c
+++ b/lib/thread.c
@@ -102,7 +102,7 @@
 	  ? a.tv_usec - b.tv_usec : a.tv_sec - b.tv_sec);
 }
 
-static unsigned long
+unsigned long
 timeval_elapsed (struct timeval a, struct timeval b)
 {
   return (((a.tv_sec - b.tv_sec) * TIMER_SECOND_MICRO)
diff --git a/lib/thread.h b/lib/thread.h
index 9743a22..4856dec 100644
--- a/lib/thread.h
+++ b/lib/thread.h
@@ -211,6 +211,7 @@
 extern void thread_call (struct thread *);
 extern unsigned long thread_timer_remain_second (struct thread *);
 extern int thread_should_yield (struct thread *);
+extern unsigned long timeval_elapsed (struct timeval a, struct timeval b);
 
 /* Internal libzebra exports */
 extern void thread_getrusage (RUSAGE_T *);
diff --git a/ospfd/ospf_abr.c b/ospfd/ospf_abr.c
index 4bb70b6..ca1af2c 100644
--- a/ospfd/ospf_abr.c
+++ b/ospfd/ospf_abr.c
@@ -556,6 +556,7 @@
 
   if (new_flags != ospf->flags)
     {
+      ospf_flag_spf_reason (SPF_FLAG_ABR_STATUS_CHANGE);
       ospf_spf_calculate_schedule (ospf);
       if (IS_DEBUG_OSPF_EVENT)
 	zlog_debug ("ospf_check_abr_status(): new router flags: %x",new_flags);
diff --git a/ospfd/ospf_asbr.c b/ospfd/ospf_asbr.c
index 7e9412c..dbf7f11 100644
--- a/ospfd/ospf_asbr.c
+++ b/ospfd/ospf_asbr.c
@@ -264,6 +264,7 @@
     }
 
   /* Transition from/to status ASBR, schedule timer. */
+  ospf_flag_spf_reason (SPF_FLAG_ASBR_STATUS_CHANGE);
   ospf_spf_calculate_schedule (ospf);
   ospf_router_lsa_update (ospf);
 }
diff --git a/ospfd/ospf_ase.c b/ospfd/ospf_ase.c
index 6a72e31..9038b3a 100644
--- a/ospfd/ospf_ase.c
+++ b/ospfd/ospf_ase.c
@@ -636,6 +636,7 @@
   struct route_node *rn;
   struct listnode *node;
   struct ospf_area *area;
+  struct timeval start_time, stop_time;
 
   ospf = THREAD_ARG (t);
   ospf->t_ase_calc = NULL;
@@ -644,6 +645,8 @@
     {
       ospf->ase_calc = 0;
 
+      quagga_gettime(QUAGGA_CLK_MONOTONIC, &start_time);
+
       /* Calculate external route for each AS-external-LSA */
       LSDB_LOOP (EXTERNAL_LSDB (ospf), rn, lsa)
 	ospf_ase_calculate_route (ospf, lsa);
@@ -673,6 +676,12 @@
       ospf_route_table_free (ospf->old_external_route);
       ospf->old_external_route = ospf->new_external_route;
       ospf->new_external_route = route_table_init ();
+
+      quagga_gettime(QUAGGA_CLK_MONOTONIC, &stop_time);
+
+      zlog_info ("SPF Processing Time(usecs): External Routes: %d\n",
+		 (stop_time.tv_sec - start_time.tv_sec)*1000000L+
+		 (stop_time.tv_usec - start_time.tv_usec));
     }
   return 0;
 }
diff --git a/ospfd/ospf_dump.c b/ospfd/ospf_dump.c
index ef02336..ebcc717 100644
--- a/ospfd/ospf_dump.c
+++ b/ospfd/ospf_dump.c
@@ -247,16 +247,21 @@
 #define HOUR_IN_SECONDS		(60*MINUTE_IN_SECONDS)
 #define DAY_IN_SECONDS		(24*HOUR_IN_SECONDS)
 #define WEEK_IN_SECONDS		(7*DAY_IN_SECONDS)
-  unsigned long w, d, h, m, s, ms;
+  unsigned long w, d, h, m, s, ms, us;
   
   if (!t)
     return "inactive";
   
-  w = d = h = m = s = ms = 0;
+  w = d = h = m = s = ms = us = 0;
   memset (buf, 0, size);
-  
-  ms = t->tv_usec / 1000;
-  
+
+  us = t->tv_usec;
+  if (us >= 1000)
+    {
+      ms = us / 1000;
+      us %= 1000;
+    }
+
   if (ms >= 1000)
     {
       t->tv_sec += ms / 1000;
@@ -297,9 +302,11 @@
     snprintf (buf, size, "%ldh%02ldm%02lds", h, m, t->tv_sec);
   else if (m)
     snprintf (buf, size, "%ldm%02lds", m, t->tv_sec);
-  else
+  else if (ms)
     snprintf (buf, size, "%ld.%03lds", t->tv_sec, ms);
-  
+  else
+    snprintf (buf, size, "%ld usecs", t->tv_usec);
+
   return buf;
 }
 
diff --git a/ospfd/ospf_lsa.c b/ospfd/ospf_lsa.c
index fef6b16..31cbaae 100644
--- a/ospfd/ospf_lsa.c
+++ b/ospfd/ospf_lsa.c
@@ -2409,8 +2409,10 @@
       ospf_refresher_register_lsa (ospf, new);
     }
   if (rt_recalc)
-    ospf_spf_calculate_schedule (ospf);
-
+    {
+      ospf_flag_spf_reason (SPF_FLAG_ROUTER_LSA_INSTALL);
+      ospf_spf_calculate_schedule (ospf);
+    }
   return new;
 }
 
@@ -2444,7 +2446,10 @@
       ospf_refresher_register_lsa (ospf, new);
     }
   if (rt_recalc)
-    ospf_spf_calculate_schedule (ospf);
+    {
+      ospf_flag_spf_reason (SPF_FLAG_NETWORK_LSA_INSTALL);
+      ospf_spf_calculate_schedule (ospf);
+    }
 
   return new;
 }
@@ -2467,11 +2472,10 @@
       /* This doesn't exist yet... */
       ospf_summary_incremental_update(new); */
 #else /* #if 0 */
+      ospf_flag_spf_reason (SPF_FLAG_SUMMARY_LSA_INSTALL);
       ospf_spf_calculate_schedule (ospf);
 #endif /* #if 0 */
  
-      if (IS_DEBUG_OSPF (lsa, LSA_INSTALL))
-	zlog_debug ("ospf_summary_lsa_install(): SPF scheduled");
     }
 
   if (IS_LSA_SELF (new))
@@ -2500,6 +2504,7 @@
 	 - RFC 2328 Section 16.5 implies it should be */
       /* ospf_ase_calculate_schedule(); */
 #else  /* #if 0 */
+      ospf_flag_spf_reason (SPF_FLAG_ASBR_SUMMARY_LSA_INSTALL);
       ospf_spf_calculate_schedule (ospf);
 #endif /* #if 0 */
     }
@@ -3022,6 +3027,7 @@
 	    ospf_ase_incremental_update (ospf, lsa);
             break;
           default:
+	    ospf_flag_spf_reason (SPF_FLAG_MAXAGE);
 	    ospf_spf_calculate_schedule (ospf);
             break;
           }
diff --git a/ospfd/ospf_spf.c b/ospfd/ospf_spf.c
index c40fc33..a7155bc 100644
--- a/ospfd/ospf_spf.c
+++ b/ospfd/ospf_spf.c
@@ -46,6 +46,50 @@
 #include "ospfd/ospf_abr.h"
 #include "ospfd/ospf_dump.h"
 
+/* Variables to ensure a SPF scheduled log message is printed only once */
+
+static unsigned int spf_reason_flags = 0;
+
+static void ospf_clear_spf_reason_flags ()
+{
+  spf_reason_flags = 0;
+}
+
+void ospf_flag_spf_reason (unsigned int reason)
+{
+  if (reason <= SPF_FLAG_MAX_VALUE)
+    spf_reason_flags |= reason;
+  else
+    spf_reason_flags |= SPF_FLAG_MISC;
+}
+
+static void
+ospf_get_spf_reason_str (char *buf)
+{
+  if (buf)
+    {
+      buf[0] = '\0';
+      if (spf_reason_flags)
+	{
+	  if (spf_reason_flags & SPF_FLAG_ROUTER_LSA_INSTALL)
+	    strcat (buf, "R, ");
+	  if (spf_reason_flags & SPF_FLAG_NETWORK_LSA_INSTALL)
+	    strcat (buf, "N, ");
+	  if (spf_reason_flags & SPF_FLAG_SUMMARY_LSA_INSTALL)
+	    strcat (buf, "S, ");
+	  if (spf_reason_flags & SPF_FLAG_ASBR_SUMMARY_LSA_INSTALL)
+	    strcat (buf, "AS, ");
+	  if (spf_reason_flags & SPF_FLAG_ABR_STATUS_CHANGE)
+	    strcat (buf, "ABR, ");
+	  if (spf_reason_flags & SPF_FLAG_ASBR_STATUS_CHANGE)
+	    strcat (buf, "ASBR, ");
+	  if (spf_reason_flags & SPF_FLAG_MAXAGE)
+	    strcat (buf, "M, ");
+      }
+      buf[strlen(buf)-2] = '\0'; /* skip the last ", " */
+    }
+}
+
 static void ospf_vertex_free (void *);
 /* List of allocated vertices, to simplify cleanup of SPF.
  * Not thread-safe obviously. If it ever needs to be, it'd have to be
@@ -1232,27 +1276,28 @@
 
   /* Free candidate queue. */
   pqueue_delete (candidate);
-  
+
   ospf_vertex_dump (__func__, area->spf, 0, 1);
   /* Free nexthop information, canonical versions of which are attached
    * the first level of router vertices attached to the root vertex, see
    * ospf_nexthop_calculation.
    */
   ospf_canonical_nexthops_free (area->spf);
-  
-  /* Free SPF vertices, but not the list. List has ospf_vertex_free
-   * as deconstructor.
-   */
-  list_delete_all_node (&vertex_list);
-  
+
   /* Increment SPF Calculation Counter. */
   area->spf_calculation++;
 
   quagga_gettime (QUAGGA_CLK_MONOTONIC, &area->ospf->ts_spf);
+  area->ts_spf = area->ospf->ts_spf;
 
   if (IS_DEBUG_OSPF_EVENT)
     zlog_debug ("ospf_spf_calculate: Stop. %ld vertices",
                 mtype_stats_alloc(MTYPE_OSPF_VERTEX));
+
+  /* Free SPF vertices, but not the list. List has ospf_vertex_free
+   * as deconstructor.
+   */
+  list_delete_all_node (&vertex_list);
 }
 
 /* Timer for SPF calculation. */
@@ -1263,12 +1308,18 @@
   struct route_table *new_table, *new_rtrs;
   struct ospf_area *area;
   struct listnode *node, *nnode;
+  struct timeval start_time, stop_time, spf_start_time;
+  int areas_processed = 0;
+  unsigned long ia_time, prune_time, rt_time;
+  unsigned long abr_time, total_spf_time, spf_time;
+  char rbuf[32];		/* reason_buf */
 
   if (IS_DEBUG_OSPF_EVENT)
     zlog_debug ("SPF: Timer (SPF calculation expire)");
 
   ospf->t_spf_calc = NULL;
 
+  quagga_gettime (QUAGGA_CLK_MONOTONIC, &spf_start_time);
   /* Allocate new table tree. */
   new_table = route_table_init ();
   new_rtrs = route_table_init ();
@@ -1283,21 +1334,36 @@
        */
       if (ospf->backbone && ospf->backbone == area)
         continue;
-      
+
       ospf_spf_calculate (area, new_table, new_rtrs);
+      areas_processed++;
     }
-  
+
   /* SPF for backbone, if required */
   if (ospf->backbone)
-    ospf_spf_calculate (ospf->backbone, new_table, new_rtrs);
-  
+    {
+      ospf_spf_calculate (ospf->backbone, new_table, new_rtrs);
+      areas_processed++;
+    }
+
+  quagga_gettime (QUAGGA_CLK_MONOTONIC, &stop_time);
+  spf_time = timeval_elapsed (stop_time, spf_start_time);
+
   ospf_vl_shut_unapproved (ospf);
 
+  start_time = stop_time;	/* saving a call */
+
   ospf_ia_routing (ospf, new_table, new_rtrs);
 
+  quagga_gettime (QUAGGA_CLK_MONOTONIC, &stop_time);
+  ia_time = timeval_elapsed (stop_time, start_time);
+
+  quagga_gettime (QUAGGA_CLK_MONOTONIC, &start_time);
   ospf_prune_unreachable_networks (new_table);
   ospf_prune_unreachable_routers (new_rtrs);
 
+  quagga_gettime (QUAGGA_CLK_MONOTONIC, &stop_time);
+  prune_time = timeval_elapsed (stop_time, start_time);
   /* AS-external-LSA calculation should not be performed here. */
 
   /* If new Router Route is installed,
@@ -1307,9 +1373,13 @@
 
   ospf_ase_calculate_timer_add (ospf);
 
+  quagga_gettime (QUAGGA_CLK_MONOTONIC, &start_time);
+
   /* Update routing table. */
   ospf_route_install (ospf, new_table);
 
+  quagga_gettime (QUAGGA_CLK_MONOTONIC, &stop_time);
+  rt_time = timeval_elapsed (stop_time, start_time);
   /* Update ABR/ASBR routing table */
   if (ospf->old_rtrs)
     {
@@ -1321,11 +1391,28 @@
   ospf->old_rtrs = ospf->new_rtrs;
   ospf->new_rtrs = new_rtrs;
 
+  quagga_gettime (QUAGGA_CLK_MONOTONIC, &start_time);
   if (IS_OSPF_ABR (ospf))
     ospf_abr_task (ospf);
 
-  if (IS_DEBUG_OSPF_EVENT)
-    zlog_debug ("SPF: calculation complete");
+  quagga_gettime (QUAGGA_CLK_MONOTONIC, &stop_time);
+  abr_time = timeval_elapsed (stop_time, start_time);
+
+  quagga_gettime (QUAGGA_CLK_MONOTONIC, &stop_time);
+  total_spf_time = timeval_elapsed (stop_time, spf_start_time);
+  ospf->ts_spf_duration.tv_sec = total_spf_time/1000000;
+  ospf->ts_spf_duration.tv_usec = total_spf_time % 1000000;
+
+  ospf_get_spf_reason_str (rbuf);
+
+  if (IS_OSPF_ABR (ospf))
+    zlog_info ("SPF Processing Time(usecs): # Areas: %d, SPF Time: %ld, InterArea: %ld, Prune: %ld, RouteInstall: %ld, ABR: %ld, Total: %ld, Reason: %s\n",
+	       areas_processed, spf_time, ia_time, prune_time, rt_time, abr_time, total_spf_time, rbuf);
+  else
+    zlog_info ("SPF Processing Time(usecs): SPF Time: %ld, InterArea: %ld, Prune: %ld, RouteInstall: %ld, Total: %ld, Reason: %s\n",
+	       spf_time, ia_time, prune_time, rt_time, total_spf_time, rbuf);
+
+  ospf_clear_spf_reason_flags ();
 
   return 0;
 }
@@ -1389,6 +1476,8 @@
   if (IS_DEBUG_OSPF_EVENT)
     zlog_debug ("SPF: calculation timer delay = %ld", delay);
 
+  zlog_info ("SPF: Scheduled in %ld msec", delay);
+
   ospf->t_spf_calc =
     thread_add_timer_msec (master, ospf_spf_calculate_timer, ospf, delay);
 }
diff --git a/ospfd/ospf_spf.h b/ospfd/ospf_spf.h
index c1316e4..c9c539a 100644
--- a/ospfd/ospf_spf.h
+++ b/ospfd/ospf_spf.h
@@ -64,4 +64,17 @@
 
 /* void ospf_spf_calculate_timer_add (); */
 
+/* What triggered the SPF ? Can have at most 32 reasons with this */
+#define SPF_FLAG_ROUTER_LSA_INSTALL 0x1
+#define SPF_FLAG_NETWORK_LSA_INSTALL 0x2
+#define SPF_FLAG_SUMMARY_LSA_INSTALL 0x4
+#define SPF_FLAG_ASBR_SUMMARY_LSA_INSTALL 0x8
+#define SPF_FLAG_MAXAGE 0x10
+#define SPF_FLAG_ABR_STATUS_CHANGE 0x20
+#define SPF_FLAG_ASBR_STATUS_CHANGE 0x40
+#define SPF_FLAG_MAX_VALUE 0x40	/* Update this when adding flags */
+#define SPF_FLAG_MISC 0x1000000	/* Keep this last */
+
+extern void ospf_flag_spf_reason (unsigned int reason);
+
 #endif /* _QUAGGA_OSPF_SPF_H */
diff --git a/ospfd/ospf_vty.c b/ospfd/ospf_vty.c
index 97fcffd..5674da0 100644
--- a/ospfd/ospf_vty.c
+++ b/ospfd/ospf_vty.c
@@ -2749,6 +2749,9 @@
       vty_out (vty, "last executed %s ago%s",
                ospf_timeval_dump (&result, timebuf, sizeof (timebuf)),
                VTY_NEWLINE);
+      vty_out (vty, " Last SPF duration %s%s",
+	       ospf_timeval_dump (&ospf->ts_spf_duration, timebuf, sizeof (timebuf)),
+	       VTY_NEWLINE);
     }
   else
     vty_out (vty, "has not been run%s", VTY_NEWLINE);
diff --git a/ospfd/ospfd.h b/ospfd/ospfd.h
index 4242aa0..bf70d02 100644
--- a/ospfd/ospfd.h
+++ b/ospfd/ospfd.h
@@ -194,8 +194,9 @@
   struct route_table *external_lsas;    /* Database of external LSAs,
 					   prefix is LSA's adv. network*/
 
-  /* Time stamps. */
+  /* Time stamps */
   struct timeval ts_spf;		/* SPF calculation time stamp. */
+  struct timeval ts_spf_duration;	/* Execution time of last SPF */
 
   struct route_table *maxage_lsa;       /* List of MaxAge LSA for deletion. */
   int redistribute;                     /* Num of redistributed protocols. */
@@ -393,6 +394,9 @@
   /* Statistics field. */
   u_int32_t spf_calculation;	/* SPF Calculation Count. */
 
+  /* Time stamps. */
+  struct timeval ts_spf;		/* SPF calculation time stamp. */
+
   /* Router count. */
   u_int32_t abr_count;		/* ABR router in this area. */
   u_int32_t asbr_count;		/* ASBR router in this area. */