three-level timer wheel implementation w/ overflow vector

prep work for s/timing_wheel/tw_timer/ in the vlib process model

Change-Id: I763f4968a8fce1764a3778b12def0afbd30086b1
Signed-off-by: Dave Barach <dave@barachs.net>

1 files changed, 701 insertions, 18 deletions

diff --git a/src/vppinfra/test_tw_timer.c b/src/vppinfra/test_tw_timer.c
index 26499509423..ec0baa07fad 100644
--- a/src/vppinfra/test_tw_timer.c
+++ b/src/vppinfra/test_tw_timer.c
@@ -3,6 +3,8 @@
 #include <vppinfra/error.h>
 #include <vppinfra/tw_timer_2t_1w_2048sl.h>
 #include <vppinfra/tw_timer_16t_2w_512sl.h>
+#include <vppinfra/tw_timer_4t_3w_256sl.h>
+#include <vppinfra/tw_timer_1t_3w_1024sl_ov.h>
 
 typedef struct
 {
@@ -10,7 +12,7 @@ typedef struct
   u32 stop_timer_handle;
 
   /** Test item should expire at this clock tick */
-  u32 expected_to_expire;
+  u64 expected_to_expire;
 } tw_timer_test_elt_t;
 
 typedef struct
@@ -24,8 +26,14 @@ typedef struct
   /** The double-wheel */
   tw_timer_wheel_16t_2w_512sl_t double_wheel;
 
+  /* The triple wheel */
+  tw_timer_wheel_4t_3w_256sl_t triple_wheel;
+
+  /* The triple wheel with overflow vector */
+  tw_timer_wheel_1t_3w_1024sl_ov_t triple_ov_wheel;
+
   /** random number seed */
-  u32 seed;
+  u64 seed;
 
   /** number of timers */
   u32 ntimers;
@@ -69,6 +77,32 @@ run_double_wheel (tw_timer_wheel_16t_2w_512sl_t * tw, u32 n_ticks)
 }
 
 static void
+run_triple_wheel (tw_timer_wheel_4t_3w_256sl_t * tw, u32 n_ticks)
+{
+  u32 i;
+  f64 now = tw->last_run_time + 1.01;
+
+  for (i = 0; i < n_ticks; i++)
+    {
+      tw_timer_expire_timers_4t_3w_256sl (tw, now);
+      now += 1.01;
+    }
+}
+
+static void
+run_triple_ov_wheel (tw_timer_wheel_1t_3w_1024sl_ov_t * tw, u32 n_ticks)
+{
+  u32 i;
+  f64 now = tw->last_run_time + 1.01;
+
+  for (i = 0; i < n_ticks; i++)
+    {
+      tw_timer_expire_timers_1t_3w_1024sl_ov (tw, now);
+      now += 1.01;
+    }
+}
+
+static void
 expired_timer_single_callback (u32 * expired_timers)
 {
   int i;
@@ -87,7 +121,7 @@ expired_timer_single_callback (u32 * expired_timers)
 
       if (e->expected_to_expire != tm->single_wheel.current_tick)
 	{
-	  fformat (stdout, "[%d] expired at %d not %d\n",
+	  fformat (stdout, "[%d] expired at %lld not %lld\n",
 		   e - tm->test_elts, tm->single_wheel.current_tick,
 		   e->expected_to_expire);
 	}
@@ -114,7 +148,7 @@ expired_timer_double_callback (u32 * expired_timers)
 
       if (e->expected_to_expire != tm->double_wheel.current_tick)
 	{
-	  fformat (stdout, "[%d] expired at %d not %d\n",
+	  fformat (stdout, "[%d] expired at %lld not %lld\n",
 		   e - tm->test_elts, tm->double_wheel.current_tick,
 		   e->expected_to_expire);
 	}
@@ -122,13 +156,64 @@ expired_timer_double_callback (u32 * expired_timers)
     }
 }
 
+static void
+expired_timer_triple_callback (u32 * expired_timers)
+{
+  int i;
+  u32 pool_index, timer_id;
+  tw_timer_test_elt_t *e;
+  tw_timer_test_main_t *tm = &tw_timer_test_main;
+
+  for (i = 0; i < vec_len (expired_timers); i++)
+    {
+      pool_index = expired_timers[i] & 0x3FFFFFFF;
+      timer_id = expired_timers[i] >> 30;
+
+      ASSERT (timer_id == 3);
+
+      e = pool_elt_at_index (tm->test_elts, pool_index);
+
+      if (e->expected_to_expire != tm->triple_wheel.current_tick)
+	{
+	  fformat (stdout, "[%d] expired at %lld not %lld\n",
+		   e - tm->test_elts, tm->triple_wheel.current_tick,
+		   e->expected_to_expire);
+	}
+      pool_put (tm->test_elts, e);
+    }
+}
+
+static void
+expired_timer_triple_ov_callback (u32 * expired_timers)
+{
+  int i;
+  u32 pool_index;
+  tw_timer_test_elt_t *e;
+  tw_timer_test_main_t *tm = &tw_timer_test_main;
+
+  for (i = 0; i < vec_len (expired_timers); i++)
+    {
+      pool_index = expired_timers[i];
+
+      e = pool_elt_at_index (tm->test_elts, pool_index);
+
+      if (e->expected_to_expire != tm->triple_ov_wheel.current_tick)
+	{
+	  fformat (stdout, "[%d] expired at %lld not %lld\n",
+		   e - tm->test_elts, tm->triple_ov_wheel.current_tick,
+		   e->expected_to_expire);
+	}
+      pool_put (tm->test_elts, e);
+    }
+}
+
 static clib_error_t *
 test2_single (tw_timer_test_main_t * tm)
 {
   u32 i, j;
   tw_timer_test_elt_t *e;
   u32 initial_wheel_offset;
-  u32 expiration_time;
+  u64 expiration_time;
   u32 max_expiration_time = 0;
   u32 *deleted_indices = 0;
   u32 adds = 0, deletes = 0;
@@ -145,7 +230,14 @@ test2_single (tw_timer_test_main_t * tm)
 
   run_single_wheel (&tm->single_wheel, initial_wheel_offset);
 
-  fformat (stdout, "test %d timers, %d iter, %d ticks per iter, 0x%x seed\n",
+  fformat (stdout, "initial wheel time %d, fast index %d\n",
+	   tm->single_wheel.current_tick,
+	   tm->single_wheel.current_index[TW_TIMER_RING_FAST]);
+
+  initial_wheel_offset = tm->single_wheel.current_tick;
+
+  fformat (stdout,
+	   "test %d timers, %d iter, %d ticks per iter, 0x%llx seed\n",
 	   tm->ntimers, tm->niter, tm->ticks_per_iter, tm->seed);
 
   before = clib_time_now (&tm->clib_time);
@@ -158,7 +250,7 @@ test2_single (tw_timer_test_main_t * tm)
 
       do
 	{
-	  expiration_time = random_u32 (&tm->seed) & (2047);
+	  expiration_time = random_u64 (&tm->seed) & (2047);
 	}
       while (expiration_time == 0);
 
@@ -192,7 +284,9 @@ test2_single (tw_timer_test_main_t * tm)
 
     del_and_re_add:
       for (j = 0; j < vec_len (deleted_indices); j++)
-	pool_put_index (tm->test_elts, deleted_indices[j]);
+	{
+	  pool_put_index (tm->test_elts, deleted_indices[j]);
+	}
 
       deletes += j;
 
@@ -203,7 +297,7 @@ test2_single (tw_timer_test_main_t * tm)
 
 	  do
 	    {
-	      expiration_time = random_u32 (&tm->seed) & (2047);
+	      expiration_time = random_u64 (&tm->seed) & (2047);
 	    }
 	  while (expiration_time == 0);
 
@@ -269,11 +363,19 @@ test2_double (tw_timer_test_main_t * tm)
 				    1.0 /* timer interval */ , ~0);
 
   /* Prime offset */
-  initial_wheel_offset = 757;
+  initial_wheel_offset = 7577;
 
   run_double_wheel (&tm->double_wheel, initial_wheel_offset);
 
-  fformat (stdout, "test %d timers, %d iter, %d ticks per iter, 0x%x seed\n",
+  fformat (stdout, "initial wheel time %d, fast index %d slow index %d\n",
+	   tm->double_wheel.current_tick,
+	   tm->double_wheel.current_index[TW_TIMER_RING_FAST],
+	   tm->double_wheel.current_index[TW_TIMER_RING_SLOW]);
+
+  initial_wheel_offset = tm->double_wheel.current_tick;
+
+  fformat (stdout,
+	   "test %d timers, %d iter, %d ticks per iter, 0x%llx seed\n",
 	   tm->ntimers, tm->niter, tm->ticks_per_iter, tm->seed);
 
   before = clib_time_now (&tm->clib_time);
@@ -286,7 +388,7 @@ test2_double (tw_timer_test_main_t * tm)
 
       do
 	{
-	  expiration_time = random_u32 (&tm->seed) & ((1 << 17) - 1);
+	  expiration_time = random_u64 (&tm->seed) & ((1 << 17) - 1);
 	}
       while (expiration_time == 0);
 
@@ -294,6 +396,7 @@ test2_double (tw_timer_test_main_t * tm)
 	max_expiration_time = expiration_time;
 
       e->expected_to_expire = expiration_time + initial_wheel_offset;
+
       e->stop_timer_handle =
 	tw_timer_start_16t_2w_512sl (&tm->double_wheel, e - tm->test_elts,
 				     14 /* timer id */ ,
@@ -331,7 +434,7 @@ test2_double (tw_timer_test_main_t * tm)
 
 	  do
 	    {
-	      expiration_time = random_u32 (&tm->seed) & ((1 << 17) - 1);
+	      expiration_time = random_u64 (&tm->seed) & ((1 << 17) - 1);
 	    }
 	  while (expiration_time == 0);
 
@@ -340,6 +443,7 @@ test2_double (tw_timer_test_main_t * tm)
 
 	  e->expected_to_expire = expiration_time +
 	    tm->double_wheel.current_tick;
+
 	  e->stop_timer_handle = tw_timer_start_16t_2w_512sl
 	    (&tm->double_wheel, e - tm->test_elts, 14 /* timer id */ ,
 	     expiration_time);
@@ -379,6 +483,291 @@ test2_double (tw_timer_test_main_t * tm)
 }
 
 static clib_error_t *
+test2_triple (tw_timer_test_main_t * tm)
+{
+  u32 i, j;
+  tw_timer_test_elt_t *e;
+  u32 initial_wheel_offset = 0;
+  u32 expiration_time;
+  u32 max_expiration_time = 0;
+  u32 *deleted_indices = 0;
+  u32 adds = 0, deletes = 0;
+  f64 before, after;
+
+  clib_time_init (&tm->clib_time);
+
+  tw_timer_wheel_init_4t_3w_256sl (&tm->triple_wheel,
+				   expired_timer_triple_callback,
+				   1.0 /* timer interval */ , ~0);
+
+
+  /* Prime offset */
+  initial_wheel_offset = 75700;
+  run_triple_wheel (&tm->triple_wheel, initial_wheel_offset);
+
+  fformat (stdout,
+	   "initial wheel time %d, fi %d si %d gi %d\n",
+	   tm->triple_wheel.current_tick,
+	   tm->triple_wheel.current_index[TW_TIMER_RING_FAST],
+	   tm->triple_wheel.current_index[TW_TIMER_RING_SLOW],
+	   tm->triple_wheel.current_index[TW_TIMER_RING_GLACIER]);
+
+  initial_wheel_offset = tm->triple_wheel.current_tick;
+
+  fformat (stdout,
+	   "test %d timers, %d iter, %d ticks per iter, 0x%llx seed\n",
+	   tm->ntimers, tm->niter, tm->ticks_per_iter, tm->seed);
+
+  before = clib_time_now (&tm->clib_time);
+
+  /* Prime the pump */
+  for (i = 0; i < tm->ntimers; i++)
+    {
+      pool_get (tm->test_elts, e);
+      memset (e, 0, sizeof (*e));
+
+      do
+	{
+	  expiration_time = random_u64 (&tm->seed) & ((1 << 17) - 1);
+	}
+      while (expiration_time == 0);
+
+      if (expiration_time > max_expiration_time)
+	max_expiration_time = expiration_time;
+
+      e->expected_to_expire = expiration_time + initial_wheel_offset;
+
+      e->stop_timer_handle =
+	tw_timer_start_4t_3w_256sl (&tm->triple_wheel, e - tm->test_elts,
+				    3 /* timer id */ ,
+				    expiration_time);
+    }
+
+  adds += i;
+
+  for (i = 0; i < tm->niter; i++)
+    {
+      run_triple_wheel (&tm->triple_wheel, tm->ticks_per_iter);
+
+      j = 0;
+      vec_reset_length (deleted_indices);
+      /* *INDENT-OFF* */
+      pool_foreach (e, tm->test_elts,
+      ({
+        tw_timer_stop_4t_3w_256sl (&tm->triple_wheel, e->stop_timer_handle);
+        vec_add1 (deleted_indices, e - tm->test_elts);
+        if (++j >= tm->ntimers / 4)
+          goto del_and_re_add;
+      }));
+      /* *INDENT-ON* */
+
+    del_and_re_add:
+      for (j = 0; j < vec_len (deleted_indices); j++)
+	pool_put_index (tm->test_elts, deleted_indices[j]);
+
+      deletes += j;
+
+      for (j = 0; j < tm->ntimers / 4; j++)
+	{
+	  pool_get (tm->test_elts, e);
+	  memset (e, 0, sizeof (*e));
+
+	  do
+	    {
+	      expiration_time = random_u64 (&tm->seed) & ((1 << 17) - 1);
+	    }
+	  while (expiration_time == 0);
+
+	  if (expiration_time > max_expiration_time)
+	    max_expiration_time = expiration_time;
+
+	  e->expected_to_expire = expiration_time +
+	    tm->triple_wheel.current_tick;
+
+	  e->stop_timer_handle = tw_timer_start_4t_3w_256sl
+	    (&tm->triple_wheel, e - tm->test_elts, 3 /* timer id */ ,
+	     expiration_time);
+	}
+      adds += j;
+    }
+
+  vec_free (deleted_indices);
+
+  run_triple_wheel (&tm->triple_wheel, max_expiration_time + 1);
+
+  after = clib_time_now (&tm->clib_time);
+
+  fformat (stdout, "%d adds, %d deletes, %d ticks\n", adds, deletes,
+	   tm->triple_wheel.current_tick);
+  fformat (stdout, "test ran %.2f seconds, %.2f ops/second\n",
+	   (after - before),
+	   ((f64) adds + (f64) deletes +
+	    (f64) tm->triple_wheel.current_tick) / (after - before));
+
+  if (pool_elts (tm->test_elts))
+    fformat (stdout, "Note: %d elements remain in pool\n",
+	     pool_elts (tm->test_elts));
+
+  /* *INDENT-OFF* */
+  pool_foreach (e, tm->test_elts,
+  ({
+    fformat (stdout, "[%d] expected to expire %d\n",
+             e - tm->test_elts,
+             e->expected_to_expire);
+  }));
+  /* *INDENT-ON* */
+
+  pool_free (tm->test_elts);
+  tw_timer_wheel_free_4t_3w_256sl (&tm->triple_wheel);
+  return 0;
+}
+
+static clib_error_t *
+test2_triple_ov (tw_timer_test_main_t * tm)
+{
+  u32 i, j;
+  tw_timer_test_elt_t *e;
+  u32 initial_wheel_offset = 0;
+  u32 expiration_time;
+  u32 max_expiration_time = 0;
+  u32 *deleted_indices = 0;
+  u32 adds = 0, deletes = 0;
+  f64 before, after;
+
+  clib_time_init (&tm->clib_time);
+
+  tw_timer_wheel_init_1t_3w_1024sl_ov (&tm->triple_ov_wheel,
+				       expired_timer_triple_ov_callback,
+				       1.0 /* timer interval */ , ~0);
+
+
+  /* Prime offset */
+  initial_wheel_offset = 75700;
+  run_triple_ov_wheel (&tm->triple_ov_wheel, initial_wheel_offset);
+
+  fformat (stdout,
+	   "initial wheel time %d, fi %d si %d gi %d\n",
+	   tm->triple_ov_wheel.current_tick,
+	   tm->triple_ov_wheel.current_index[TW_TIMER_RING_FAST],
+	   tm->triple_ov_wheel.current_index[TW_TIMER_RING_SLOW],
+	   tm->triple_ov_wheel.current_index[TW_TIMER_RING_GLACIER]);
+
+  initial_wheel_offset = tm->triple_ov_wheel.current_tick;
+
+  fformat (stdout,
+	   "test %d timers, %d iter, %d ticks per iter, 0x%llx seed\n",
+	   tm->ntimers, tm->niter, tm->ticks_per_iter, tm->seed);
+
+  before = clib_time_now (&tm->clib_time);
+
+  /* Prime the pump */
+  for (i = 0; i < tm->ntimers; i++)
+    {
+      pool_get (tm->test_elts, e);
+      memset (e, 0, sizeof (*e));
+
+      do
+	{
+	  expiration_time = random_u64 (&tm->seed) & ((1 << 17) - 1);
+	}
+      while (expiration_time == 0);
+
+      if (expiration_time > max_expiration_time)
+	max_expiration_time = expiration_time;
+
+      e->expected_to_expire = expiration_time + initial_wheel_offset;
+
+      e->stop_timer_handle =
+	tw_timer_start_1t_3w_1024sl_ov (&tm->triple_ov_wheel,
+					e - tm->test_elts, 0 /* timer id */ ,
+					expiration_time);
+    }
+
+  adds += i;
+
+  for (i = 0; i < tm->niter; i++)
+    {
+      run_triple_ov_wheel (&tm->triple_ov_wheel, tm->ticks_per_iter);
+
+      j = 0;
+      vec_reset_length (deleted_indices);
+      /* *INDENT-OFF* */
+      pool_foreach (e, tm->test_elts,
+      ({
+        tw_timer_stop_1t_3w_1024sl_ov (&tm->triple_ov_wheel,
+                                       e->stop_timer_handle);
+        vec_add1 (deleted_indices, e - tm->test_elts);
+        if (++j >= tm->ntimers / 4)
+          goto del_and_re_add;
+      }));
+      /* *INDENT-ON* */
+
+    del_and_re_add:
+      for (j = 0; j < vec_len (deleted_indices); j++)
+	pool_put_index (tm->test_elts, deleted_indices[j]);
+
+      deletes += j;
+
+      for (j = 0; j < tm->ntimers / 4; j++)
+	{
+	  pool_get (tm->test_elts, e);
+	  memset (e, 0, sizeof (*e));
+
+	  do
+	    {
+	      expiration_time = random_u64 (&tm->seed) & ((1 << 17) - 1);
+	    }
+	  while (expiration_time == 0);
+
+	  if (expiration_time > max_expiration_time)
+	    max_expiration_time = expiration_time;
+
+	  e->expected_to_expire = expiration_time +
+	    tm->triple_ov_wheel.current_tick;
+
+	  e->stop_timer_handle = tw_timer_start_1t_3w_1024sl_ov
+	    (&tm->triple_ov_wheel, e - tm->test_elts, 0 /* timer id */ ,
+	     expiration_time);
+	}
+      adds += j;
+    }
+
+  vec_free (deleted_indices);
+
+  run_triple_ov_wheel (&tm->triple_ov_wheel, max_expiration_time + 1);
+
+  after = clib_time_now (&tm->clib_time);
+
+  fformat (stdout, "%d adds, %d deletes, %d ticks\n", adds, deletes,
+	   tm->triple_ov_wheel.current_tick);
+  fformat (stdout, "test ran %.2f seconds, %.2f ops/second\n",
+	   (after - before),
+	   ((f64) adds + (f64) deletes +
+	    (f64) tm->triple_ov_wheel.current_tick) / (after - before));
+
+  if (pool_elts (tm->test_elts))
+    fformat (stdout, "Note: %d elements remain in pool\n",
+	     pool_elts (tm->test_elts));
+
+  /* *INDENT-OFF* */
+  pool_foreach (e, tm->test_elts,
+  ({
+    TWT (tw_timer) * t;
+
+    fformat (stdout, "[%d] expected to expire %d\n",
+             e - tm->test_elts,
+             e->expected_to_expire);
+    t = pool_elt_at_index (tm->triple_ov_wheel.timers, e->stop_timer_handle);
+    fformat (stdout, "  expiration_time %lld\n", t->expiration_time);
+  }));
+  /* *INDENT-ON* */
+
+  pool_free (tm->test_elts);
+  tw_timer_wheel_free_1t_3w_1024sl_ov (&tm->triple_ov_wheel);
+  return 0;
+}
+
+static clib_error_t *
 test1_single (tw_timer_test_main_t * tm)
 {
   u32 i;
@@ -401,6 +790,8 @@ test1_single (tw_timer_test_main_t * tm)
 	   tm->single_wheel.current_tick,
 	   tm->single_wheel.current_index[TW_TIMER_RING_FAST]);
 
+  offset = tm->single_wheel.current_tick;
+
   for (i = 0; i < tm->ntimers; i++)
     {
       u32 expected_to_expire;
@@ -504,28 +895,283 @@ test1_double (tw_timer_test_main_t * tm)
 }
 
 static clib_error_t *
+test3_triple_double (tw_timer_test_main_t * tm)
+{
+  tw_timer_test_elt_t *e;
+  u32 initial_wheel_offset = 0;
+  u32 expiration_time;
+  u32 max_expiration_time = 0;
+  u32 adds = 0, deletes = 0;
+  f64 before, after;
+
+  clib_time_init (&tm->clib_time);
+
+  tw_timer_wheel_init_4t_3w_256sl (&tm->triple_wheel,
+				   expired_timer_triple_callback,
+				   1.0 /* timer interval */ , ~0);
+
+  initial_wheel_offset = 0;
+  run_triple_wheel (&tm->triple_wheel, initial_wheel_offset);
+
+  fformat (stdout,
+	   "initial wheel time %d, fi %d si %d gi %d\n",
+	   tm->triple_wheel.current_tick,
+	   tm->triple_wheel.current_index[TW_TIMER_RING_FAST],
+	   tm->triple_wheel.current_index[TW_TIMER_RING_SLOW],
+	   tm->triple_wheel.current_index[TW_TIMER_RING_GLACIER]);
+
+  initial_wheel_offset = tm->triple_wheel.current_tick;
+
+  fformat (stdout, "Create a timer which expires at wheel-time (1, 0, 0)\n");
+
+  before = clib_time_now (&tm->clib_time);
+
+  /* Prime the pump */
+  pool_get (tm->test_elts, e);
+  memset (e, 0, sizeof (*e));
+
+  /* 1 glacier ring tick from now */
+  expiration_time = TW_SLOTS_PER_RING * TW_SLOTS_PER_RING;
+  e->expected_to_expire = expiration_time + initial_wheel_offset;
+  max_expiration_time = expiration_time;
+
+  e->stop_timer_handle =
+    tw_timer_start_4t_3w_256sl (&tm->triple_wheel, e - tm->test_elts,
+				3 /* timer id */ ,
+				expiration_time);
+
+  run_triple_wheel (&tm->triple_wheel, max_expiration_time + 1);
+
+  after = clib_time_now (&tm->clib_time);
+
+  fformat (stdout, "%d adds, %d deletes, %d ticks\n", adds, deletes,
+	   tm->triple_wheel.current_tick);
+  fformat (stdout, "test ran %.2f seconds, %.2f ops/second\n",
+	   (after - before),
+	   ((f64) adds + (f64) deletes +
+	    (f64) tm->triple_wheel.current_tick) / (after - before));
+
+  if (pool_elts (tm->test_elts))
+    fformat (stdout, "Note: %d elements remain in pool\n",
+	     pool_elts (tm->test_elts));
+
+  /* *INDENT-OFF* */
+  pool_foreach (e, tm->test_elts,
+  ({
+    fformat (stdout, "[%d] expected to expire %d\n",
+             e - tm->test_elts,
+             e->expected_to_expire);
+  }));
+  /* *INDENT-ON* */
+
+  pool_free (tm->test_elts);
+  tw_timer_wheel_free_4t_3w_256sl (&tm->triple_wheel);
+  return 0;
+}
+
+static clib_error_t *
+test4_double_double (tw_timer_test_main_t * tm)
+{
+  u32 i;
+  tw_timer_test_elt_t *e;
+  u32 initial_wheel_offset;
+  u32 expiration_time;
+  u32 max_expiration_time = 0;
+  u32 *deleted_indices = 0;
+  u32 adds = 0, deletes = 0;
+  f64 before, after;
+
+  clib_time_init (&tm->clib_time);
+
+  tw_timer_wheel_init_16t_2w_512sl (&tm->double_wheel,
+				    expired_timer_double_callback,
+				    1.0 /* timer interval */ , ~0);
+  /* Prime offset */
+  initial_wheel_offset = 0;
+
+  run_double_wheel (&tm->double_wheel, initial_wheel_offset);
+
+  fformat (stdout, "initial wheel time %d, fast index %d slow index %d\n",
+	   tm->double_wheel.current_tick,
+	   tm->double_wheel.current_index[TW_TIMER_RING_FAST],
+	   tm->double_wheel.current_index[TW_TIMER_RING_SLOW]);
+
+  initial_wheel_offset = tm->double_wheel.current_tick;
+
+  fformat (stdout, "test timer which expires at 512 ticks\n");
+
+  before = clib_time_now (&tm->clib_time);
+
+  /* Prime the pump */
+  for (i = 0; i < tm->ntimers; i++)
+    {
+      pool_get (tm->test_elts, e);
+      memset (e, 0, sizeof (*e));
+
+      expiration_time = 512;
+
+      if (expiration_time > max_expiration_time)
+	max_expiration_time = expiration_time;
+
+      e->expected_to_expire = expiration_time + initial_wheel_offset;
+      e->stop_timer_handle =
+	tw_timer_start_16t_2w_512sl (&tm->double_wheel, e - tm->test_elts,
+				     14 /* timer id */ ,
+				     expiration_time);
+    }
+
+  adds = 1;
+
+  vec_free (deleted_indices);
+
+  run_double_wheel (&tm->double_wheel, max_expiration_time + 1);
+
+  after = clib_time_now (&tm->clib_time);
+
+  fformat (stdout, "%d adds, %d deletes, %d ticks\n", adds, deletes,
+	   tm->double_wheel.current_tick);
+  fformat (stdout, "test ran %.2f seconds, %.2f ops/second\n",
+	   (after - before),
+	   ((f64) adds + (f64) deletes +
+	    (f64) tm->double_wheel.current_tick) / (after - before));
+
+  if (pool_elts (tm->test_elts))
+    fformat (stdout, "Note: %d elements remain in pool\n",
+	     pool_elts (tm->test_elts));
+
+  /* *INDENT-OFF* */
+  pool_foreach (e, tm->test_elts,
+  ({
+    fformat (stdout, "[%d] expected to expire %d\n",
+             e - tm->test_elts,
+             e->expected_to_expire);
+  }));
+  /* *INDENT-ON* */
+
+  pool_free (tm->test_elts);
+  tw_timer_wheel_free_16t_2w_512sl (&tm->double_wheel);
+  return 0;
+}
+
+static clib_error_t *
+test5_double (tw_timer_test_main_t * tm)
+{
+  u32 i;
+  tw_timer_test_elt_t *e;
+  u32 initial_wheel_offset;
+  u32 expiration_time;
+  u32 max_expiration_time = 0;
+  u32 adds = 0, deletes = 0;
+  f64 before, after;
+
+  clib_time_init (&tm->clib_time);
+
+  tw_timer_wheel_init_16t_2w_512sl (&tm->double_wheel,
+				    expired_timer_double_callback,
+				    1.0 /* timer interval */ , ~0);
+
+  /* Prime offset */
+  initial_wheel_offset = 7567;
+
+  run_double_wheel (&tm->double_wheel, initial_wheel_offset);
+
+  fformat (stdout, "initial wheel time %d, fast index %d slow index %d\n",
+	   tm->double_wheel.current_tick,
+	   tm->double_wheel.current_index[TW_TIMER_RING_FAST],
+	   tm->double_wheel.current_index[TW_TIMER_RING_SLOW]);
+
+  initial_wheel_offset = tm->double_wheel.current_tick;
+
+  fformat (stdout,
+	   "test %d timers, %d iter, %d ticks per iter, 0x%llx seed\n",
+	   tm->ntimers, tm->niter, tm->ticks_per_iter, tm->seed);
+
+  before = clib_time_now (&tm->clib_time);
+
+  /* Prime the pump */
+  for (i = 0; i < tm->ntimers; i++)
+    {
+      pool_get (tm->test_elts, e);
+      memset (e, 0, sizeof (*e));
+
+      expiration_time = i + 1;
+
+      if (expiration_time > max_expiration_time)
+	max_expiration_time = expiration_time;
+
+      e->expected_to_expire = expiration_time + initial_wheel_offset;
+      e->stop_timer_handle =
+	tw_timer_start_16t_2w_512sl (&tm->double_wheel, e - tm->test_elts,
+				     14 /* timer id */ ,
+				     expiration_time);
+    }
+
+  adds += i;
+
+  run_double_wheel (&tm->double_wheel, max_expiration_time + 1);
+
+  after = clib_time_now (&tm->clib_time);
+
+  fformat (stdout, "%d adds, %d deletes, %d ticks\n", adds, deletes,
+	   tm->double_wheel.current_tick);
+  fformat (stdout, "test ran %.2f seconds, %.2f ops/second\n",
+	   (after - before),
+	   ((f64) adds + (f64) deletes +
+	    (f64) tm->double_wheel.current_tick) / (after - before));
+
+  if (pool_elts (tm->test_elts))
+    fformat (stdout, "Note: %d elements remain in pool\n",
+	     pool_elts (tm->test_elts));
+
+  /* *INDENT-OFF* */
+  pool_foreach (e, tm->test_elts,
+  ({
+    fformat (stdout, "[%d] expected to expire %d\n",
+             e - tm->test_elts,
+             e->expected_to_expire);
+  }));
+  /* *INDENT-ON* */
+
+  pool_free (tm->test_elts);
+  tw_timer_wheel_free_16t_2w_512sl (&tm->double_wheel);
+  return 0;
+}
+
+static clib_error_t *
 timer_test_command_fn (tw_timer_test_main_t * tm, unformat_input_t * input)
 {
 
   int is_test1 = 0;
   int num_wheels = 1;
   int is_test2 = 0;
+  int is_test3 = 0;
+  int is_test4 = 0;
+  int is_test5 = 0;
+  int overflow = 0;
 
   memset (tm, 0, sizeof (*tm));
   /* Default values */
   tm->ntimers = 100000;
-  tm->seed = 0xDEADDABE;
+  tm->seed = 0xDEADDABEB00BFACE;
   tm->niter = 1000;
   tm->ticks_per_iter = 727;
 
   while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
     {
-      if (unformat (input, "seed %d", &tm->seed))
+      if (unformat (input, "seed %lld", &tm->seed))
 	;
       else if (unformat (input, "test1"))
 	is_test1 = 1;
       else if (unformat (input, "test2"))
 	is_test2 = 1;
+      else if (unformat (input, "overflow"))
+	overflow = 1;
+      else if (unformat (input, "lebron"))
+	is_test3 = 1;
+      else if (unformat (input, "wilt"))
+	is_test4 = 1;
+      else if (unformat (input, "linear"))
+	is_test5 = 1;
       else if (unformat (input, "wheels %d", &num_wheels))
 	;
       else if (unformat (input, "ntimers %d", &tm->ntimers))
@@ -534,12 +1180,14 @@ timer_test_command_fn (tw_timer_test_main_t * tm, unformat_input_t * input)
 	;
       else if (unformat (input, "ticks_per_iter %d", &tm->ticks_per_iter))
 	;
+      else
+	break;
     }
 
-  if (is_test1 + is_test2 == 0)
+  if (is_test1 + is_test2 + is_test3 + is_test4 + is_test5 == 0)
     return clib_error_return (0, "No test specified [test1..n]");
 
-  if (num_wheels < 1 || num_wheels > 2)
+  if (num_wheels < 1 || num_wheels > 3)
     return clib_error_return (0, "unsupported... 1 or 2 wheels only");
 
   if (is_test1)
@@ -553,9 +1201,25 @@ timer_test_command_fn (tw_timer_test_main_t * tm, unformat_input_t * input)
     {
       if (num_wheels == 1)
 	return test2_single (tm);
-      else
+      else if (num_wheels == 2)
 	return test2_double (tm);
+      else if (num_wheels == 3)
+	{
+	  if (overflow == 0)
+	    return test2_triple (tm);
+	  else
+	    return test2_triple_ov (tm);
+	}
     }
+  if (is_test3)
+    return test3_triple_double (tm);
+
+  if (is_test4)
+    return test4_double_double (tm);
+
+  if (is_test5)
+    return test5_double (tm);
+
   /* NOTREACHED */
   return 0;
 }
@@ -583,6 +1247,25 @@ main (int argc, char *argv[])
 }
 #endif /* CLIB_UNIX */
 
+/* For debugging... */
+int
+pifi (void *p, u32 index)
+{
+  return pool_is_free_index (p, index);
+}
+
+u32
+vl (void *p)
+{
+  return vec_len (p);
+}
+
+uword
+pe (void *v)
+{
+  return (pool_elts (v));
+}
+
 /*
  * fd.io coding-style-patch-verification: ON
  *