src/vppinfra/tw_timer_template.c - fdio/vpp - Gitiles

 /*
  * Copyright (c) 2016 Cisco and/or its affiliates.
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at:
  *
  *     http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 /** @file
  *  @brief TW timer implementation TEMPLATE ONLY, do not compile directly
  *
  *
  */

 static inline u32
 TW (make_internal_timer_handle) (u32 pool_index, u32 timer_id)
 {
   u32 handle;

   ASSERT (timer_id < TW_TIMERS_PER_OBJECT);
   ASSERT (pool_index < (1 << (32 - LOG2_TW_TIMERS_PER_OBJECT)));

   handle = (timer_id << (32 - LOG2_TW_TIMERS_PER_OBJECT)) | (pool_index);
   return handle;
 }

 static inline void
 timer_addhead (TWT (tw_timer) * pool, u32 head_index, u32 new_index)
 {
   TWT (tw_timer) * head = pool_elt_at_index (pool, head_index);
   TWT (tw_timer) * old_first;
   u32 old_first_index;
   TWT (tw_timer) * new;

   new = pool_elt_at_index (pool, new_index);

   if (PREDICT_FALSE (head->next == head_index))
     {
       head->next = head->prev = new_index;
       new->next = new->prev = head_index;
       return;
     }

   old_first_index = head->next;
   old_first = pool_elt_at_index (pool, old_first_index);

   new->next = old_first_index;
   new->prev = old_first->prev;
   old_first->prev = new_index;
   head->next = new_index;
 }

 static inline void
 timer_remove (TWT (tw_timer) * pool, u32 index)
 {
   TWT (tw_timer) * elt = pool_elt_at_index (pool, index);
   TWT (tw_timer) * next_elt, *prev_elt;

   ASSERT (elt->user_handle != ~0);

   next_elt = pool_elt_at_index (pool, elt->next);
   prev_elt = pool_elt_at_index (pool, elt->prev);

   next_elt->prev = elt->prev;
   prev_elt->next = elt->next;

   elt->prev = elt->next = ~0;
 }

 /**
  * @brief Start a Tw Timer
  * @param tw_timer_wheel_t * tw timer wheel object pointer
  * @param u32 pool_index user pool index, presumably for a tw session
  * @param u32 timer_id app-specific timer ID. 4 bits.
  * @param u32 interval timer interval in ticks
  * @returns handle needed to cancel the timer
  */
 u32
 TW (tw_timer_start) (TWT (tw_timer_wheel) * tw, u32 pool_index, u32 timer_id,
 		     u32 interval)
 {
 #if TW_TIMER_WHEELS > 1
   u16 slow_ring_offset;
   u32 carry;
 #endif
   u16 fast_ring_offset;
   tw_timer_wheel_slot_t *ts;
   TWT (tw_timer) * t;

   ASSERT (interval);

   pool_get (tw->timers, t);
   t->next = t->prev = ~0;
 #if TW_TIMER_WHEELS > 1
   t->fast_ring_offset = ~0;
 #endif
   t->user_handle = TW (make_internal_timer_handle) (pool_index, timer_id);

   fast_ring_offset = interval & TW_RING_MASK;
   fast_ring_offset += tw->current_index[TW_TIMER_RING_FAST];
 #if TW_TIMER_WHEELS > 1
   carry = fast_ring_offset >= TW_SLOTS_PER_RING ? 1 : 0;
   fast_ring_offset %= TW_SLOTS_PER_RING;
   slow_ring_offset = (interval >> TW_RING_SHIFT) + carry;

   /* Timer duration exceeds ~7 hrs? Oops */
   ASSERT (slow_ring_offset < TW_SLOTS_PER_RING);

   /* Timer expires more than 51.2 seconds from now? */
   if (slow_ring_offset)
     {
       slow_ring_offset += tw->current_index[TW_TIMER_RING_SLOW];
       slow_ring_offset %= TW_SLOTS_PER_RING;

       /* We'll want the fast ring offset later... */
       t->fast_ring_offset = fast_ring_offset;
       ASSERT (t->fast_ring_offset < TW_SLOTS_PER_RING);

       ts = &tw->w[TW_TIMER_RING_SLOW][slow_ring_offset];

       timer_addhead (tw->timers, ts->head_index, t - tw->timers);

       return t - tw->timers;
     }
 #else
   fast_ring_offset %= TW_SLOTS_PER_RING;
   ASSERT (interval < TW_SLOTS_PER_RING);
 #endif

   /* Timer expires less than one fast-ring revolution from now */
   ts = &tw->w[TW_TIMER_RING_FAST][fast_ring_offset];

   timer_addhead (tw->timers, ts->head_index, t - tw->timers);
   return t - tw->timers;
 }

 /**
  * @brief Stop a tw timer
  * @param tw_timer_wheel_t * tw timer wheel object pointer
  * @param u32 handle timer cancellation returned by tw_timer_start
  */
 void TW (tw_timer_stop) (TWT (tw_timer_wheel) * tw, u32 handle)
 {
   TWT (tw_timer) * t;

   t = pool_elt_at_index (tw->timers, handle);

   /* in case of idiotic handle (e.g. passing a listhead index) */
   ASSERT (t->user_handle != ~0);

   timer_remove (tw->timers, handle);

   pool_put_index (tw->timers, handle);
 }

 /**
  * @brief Initialize a tw timer wheel template instance
  * @param tw_timer_wheel_t * tw timer wheel object pointer
  * @param void * expired_timer_callback. Passed a u32 * vector of
  *   expired timer handles.
  * @param f64 timer_interval_in_seconds
  */
 void
 TW (tw_timer_wheel_init) (TWT (tw_timer_wheel) * tw,
 			  void *expired_timer_callback,
 			  f64 timer_interval_in_seconds, u32 max_expirations)
 {
   int ring, slot;
   tw_timer_wheel_slot_t *ts;
   TWT (tw_timer) * t;
   memset (tw, 0, sizeof (*tw));
   tw->expired_timer_callback = expired_timer_callback;
   tw->max_expirations = max_expirations;
   if (timer_interval_in_seconds == 0.0)
     {
       clib_warning ("timer interval is zero");
       abort ();
     }
   tw->timer_interval = timer_interval_in_seconds;
   tw->ticks_per_second = 1.0 / timer_interval_in_seconds;

   for (ring = 0; ring < TW_TIMER_WHEELS; ring++)
     {
       for (slot = 0; slot < TW_SLOTS_PER_RING; slot++)
 	{
 	  ts = &tw->w[ring][slot];
 	  pool_get (tw->timers, t);
 	  memset (t, 0xff, sizeof (*t));
 	  t->next = t->prev = t - tw->timers;
 	  ts->head_index = t - tw->timers;
 	}
     }
 }

 /**
  * @brief Free a tw timer wheel template instance
  * @param tw_timer_wheel_t * tw timer wheel object pointer
  */
 void TW (tw_timer_wheel_free) (TWT (tw_timer_wheel) * tw)
 {
   int i, j;
   tw_timer_wheel_slot_t *ts;
   TWT (tw_timer) * head, *t;
   u32 next_index;

   for (i = 0; i < TW_TIMER_WHEELS; i++)
     {
       for (j = 0; j < TW_SLOTS_PER_RING; j++)
 	{
 	  ts = &tw->w[i][j];
 	  head = pool_elt_at_index (tw->timers, ts->head_index);
 	  next_index = head->next;

 	  while (next_index != ts->head_index)
 	    {
 	      t = pool_elt_at_index (tw->timers, next_index);
 	      next_index = t->next;
 	      pool_put (tw->timers, t);
 	    }
 	  pool_put (tw->timers, head);
 	}
     }
   memset (tw, 0, sizeof (*tw));
 }

 /**
  * @brief Advance a tw timer wheel. Calls the expired timer callback
  * as needed. This routine should be called once every timer_interval seconds
  * @param tw_timer_wheel_t * tw timer wheel template instance pointer
  * @param f64 now the current time, e.g. from vlib_time_now(vm)
  */
 u32 TW (tw_timer_expire_timers) (TWT (tw_timer_wheel) * tw, f64 now)
 {
   u32 nticks, i;
   tw_timer_wheel_slot_t *ts;
   TWT (tw_timer) * t, *head;
   u32 fast_wheel_index;
   u32 next_index;
   u32 nexpirations, total_nexpirations;
 #if TW_TIMER_WHEELS > 1
   u32 slow_wheel_index;
 #endif

   /* Shouldn't happen */
   if (PREDICT_FALSE (now < tw->next_run_time))
     return 0;

   /* Number of ticks which have occurred */
   nticks = tw->ticks_per_second * (now - tw->last_run_time);
   if (nticks == 0)
     return 0;

   /* Remember when we ran, compute next runtime */
   tw->next_run_time = (now + tw->timer_interval);

   total_nexpirations = 0;
   for (i = 0; i < nticks; i++)
     {
       fast_wheel_index = tw->current_index[TW_TIMER_RING_FAST];

       /*
        * If we've been around the fast ring once,
        * process one slot in the slow ring before we handle
        * the fast ring.
        */
       if (PREDICT_FALSE (fast_wheel_index == TW_SLOTS_PER_RING))
 	{
 	  fast_wheel_index = tw->current_index[TW_TIMER_RING_FAST] = 0;

 #if TW_TIMER_WHEELS > 1
 	  tw->current_index[TW_TIMER_RING_SLOW]++;
 	  tw->current_index[TW_TIMER_RING_SLOW] %= TW_SLOTS_PER_RING;
 	  slow_wheel_index = tw->current_index[TW_TIMER_RING_SLOW];

 	  ts = &tw->w[TW_TIMER_RING_SLOW][slow_wheel_index];

 	  head = pool_elt_at_index (tw->timers, ts->head_index);
 	  next_index = head->next;

 	  /* Make slot empty */
 	  head->next = head->prev = ts->head_index;

 	  /* traverse slot, deal timers into fast ring */
 	  while (next_index != head - tw->timers)
 	    {
 	      t = pool_elt_at_index (tw->timers, next_index);
 	      next_index = t->next;

 	      /* Remove from slow ring slot (hammer) */
 	      t->next = t->prev = ~0;
 	      ASSERT (t->fast_ring_offset < TW_SLOTS_PER_RING);
 	      /* Add to fast ring */
 	      ts = &tw->w[TW_TIMER_RING_FAST][t->fast_ring_offset];
 	      timer_addhead (tw->timers, ts->head_index, t - tw->timers);
 	    }
 #endif
 	}

       /* Handle the fast ring */
       vec_reset_length (tw->expired_timer_handles);

       ts = &tw->w[TW_TIMER_RING_FAST][fast_wheel_index];

       head = pool_elt_at_index (tw->timers, ts->head_index);
       next_index = head->next;

       /* Make slot empty */
       head->next = head->prev = ts->head_index;

       /* Construct vector of expired timer handles to give the user */
       while (next_index != ts->head_index)
 	{
 	  t = pool_elt_at_index (tw->timers, next_index);
 	  next_index = t->next;
 	  vec_add1 (tw->expired_timer_handles, t->user_handle);
 	  pool_put (tw->timers, t);
 	}

       /* If any timers expired, tell the user */
       nexpirations = vec_len (tw->expired_timer_handles);
       if (nexpirations)
 	{
 	  tw->expired_timer_callback (tw->expired_timer_handles);
 	  total_nexpirations += nexpirations;
 	}
       tw->current_index[TW_TIMER_RING_FAST]++;
       tw->current_tick++;

       if (total_nexpirations >= tw->max_expirations)
 	break;
     }

   tw->last_run_time += i * tw->timer_interval;
   return total_nexpirations;
 }

 /*
  * fd.io coding-style-patch-verification: ON
  *
  * Local Variables:
  * eval: (c-set-style "gnu")
  * End:
  */
	/*
	* Copyright (c) 2016 Cisco and/or its affiliates.
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at:
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	/** @file
	* @brief TW timer implementation TEMPLATE ONLY, do not compile directly
	*
	*
	*/

	static inline u32
	TW (make_internal_timer_handle) (u32 pool_index, u32 timer_id)
	{
	u32 handle;

	ASSERT (timer_id < TW_TIMERS_PER_OBJECT);
	ASSERT (pool_index < (1 << (32 - LOG2_TW_TIMERS_PER_OBJECT)));

	handle = (timer_id << (32 - LOG2_TW_TIMERS_PER_OBJECT)) \| (pool_index);
	return handle;
	}

	static inline void
	timer_addhead (TWT (tw_timer) * pool, u32 head_index, u32 new_index)
	{
	TWT (tw_timer) * head = pool_elt_at_index (pool, head_index);
	TWT (tw_timer) * old_first;
	u32 old_first_index;
	TWT (tw_timer) * new;

	new = pool_elt_at_index (pool, new_index);

	if (PREDICT_FALSE (head->next == head_index))
	{
	head->next = head->prev = new_index;
	new->next = new->prev = head_index;
	return;
	}

	old_first_index = head->next;
	old_first = pool_elt_at_index (pool, old_first_index);

	new->next = old_first_index;
	new->prev = old_first->prev;
	old_first->prev = new_index;
	head->next = new_index;
	}

	static inline void
	timer_remove (TWT (tw_timer) * pool, u32 index)
	{
	TWT (tw_timer) * elt = pool_elt_at_index (pool, index);
	TWT (tw_timer) * next_elt, *prev_elt;

	ASSERT (elt->user_handle != ~0);

	next_elt = pool_elt_at_index (pool, elt->next);
	prev_elt = pool_elt_at_index (pool, elt->prev);

	next_elt->prev = elt->prev;
	prev_elt->next = elt->next;

	elt->prev = elt->next = ~0;
	}

	/**
	* @brief Start a Tw Timer
	* @param tw_timer_wheel_t * tw timer wheel object pointer
	* @param u32 pool_index user pool index, presumably for a tw session
	* @param u32 timer_id app-specific timer ID. 4 bits.
	* @param u32 interval timer interval in ticks
	* @returns handle needed to cancel the timer
	*/
	u32
	TW (tw_timer_start) (TWT (tw_timer_wheel) * tw, u32 pool_index, u32 timer_id,
	u32 interval)
	{
	#if TW_TIMER_WHEELS > 1
	u16 slow_ring_offset;
	u32 carry;
	#endif
	u16 fast_ring_offset;
	tw_timer_wheel_slot_t *ts;
	TWT (tw_timer) * t;

	ASSERT (interval);

	pool_get (tw->timers, t);
	t->next = t->prev = ~0;
	#if TW_TIMER_WHEELS > 1
	t->fast_ring_offset = ~0;
	#endif
	t->user_handle = TW (make_internal_timer_handle) (pool_index, timer_id);

	fast_ring_offset = interval & TW_RING_MASK;
	fast_ring_offset += tw->current_index[TW_TIMER_RING_FAST];
	#if TW_TIMER_WHEELS > 1
	carry = fast_ring_offset >= TW_SLOTS_PER_RING ? 1 : 0;
	fast_ring_offset %= TW_SLOTS_PER_RING;
	slow_ring_offset = (interval >> TW_RING_SHIFT) + carry;

	/* Timer duration exceeds ~7 hrs? Oops */
	ASSERT (slow_ring_offset < TW_SLOTS_PER_RING);

	/* Timer expires more than 51.2 seconds from now? */
	if (slow_ring_offset)
	{
	slow_ring_offset += tw->current_index[TW_TIMER_RING_SLOW];
	slow_ring_offset %= TW_SLOTS_PER_RING;

	/* We'll want the fast ring offset later... */
	t->fast_ring_offset = fast_ring_offset;
	ASSERT (t->fast_ring_offset < TW_SLOTS_PER_RING);

	ts = &tw->w[TW_TIMER_RING_SLOW][slow_ring_offset];

	timer_addhead (tw->timers, ts->head_index, t - tw->timers);

	return t - tw->timers;
	}
	#else
	fast_ring_offset %= TW_SLOTS_PER_RING;
	ASSERT (interval < TW_SLOTS_PER_RING);
	#endif

	/* Timer expires less than one fast-ring revolution from now */
	ts = &tw->w[TW_TIMER_RING_FAST][fast_ring_offset];

	timer_addhead (tw->timers, ts->head_index, t - tw->timers);
	return t - tw->timers;
	}

	/**
	* @brief Stop a tw timer
	* @param tw_timer_wheel_t * tw timer wheel object pointer
	* @param u32 handle timer cancellation returned by tw_timer_start
	*/
	void TW (tw_timer_stop) (TWT (tw_timer_wheel) * tw, u32 handle)
	{
	TWT (tw_timer) * t;

	t = pool_elt_at_index (tw->timers, handle);

	/* in case of idiotic handle (e.g. passing a listhead index) */
	ASSERT (t->user_handle != ~0);

	timer_remove (tw->timers, handle);

	pool_put_index (tw->timers, handle);
	}

	/**
	* @brief Initialize a tw timer wheel template instance
	* @param tw_timer_wheel_t * tw timer wheel object pointer
	* @param void * expired_timer_callback. Passed a u32 * vector of
	* expired timer handles.
	* @param f64 timer_interval_in_seconds
	*/
	void
	TW (tw_timer_wheel_init) (TWT (tw_timer_wheel) * tw,
	void *expired_timer_callback,
	f64 timer_interval_in_seconds, u32 max_expirations)
	{
	int ring, slot;
	tw_timer_wheel_slot_t *ts;
	TWT (tw_timer) * t;
	memset (tw, 0, sizeof (*tw));
	tw->expired_timer_callback = expired_timer_callback;
	tw->max_expirations = max_expirations;
	if (timer_interval_in_seconds == 0.0)
	{
	clib_warning ("timer interval is zero");
	abort ();
	}
	tw->timer_interval = timer_interval_in_seconds;
	tw->ticks_per_second = 1.0 / timer_interval_in_seconds;

	for (ring = 0; ring < TW_TIMER_WHEELS; ring++)
	{
	for (slot = 0; slot < TW_SLOTS_PER_RING; slot++)
	{
	ts = &tw->w[ring][slot];
	pool_get (tw->timers, t);
	memset (t, 0xff, sizeof (*t));
	t->next = t->prev = t - tw->timers;
	ts->head_index = t - tw->timers;
	}
	}
	}

	/**
	* @brief Free a tw timer wheel template instance
	* @param tw_timer_wheel_t * tw timer wheel object pointer
	*/
	void TW (tw_timer_wheel_free) (TWT (tw_timer_wheel) * tw)
	{
	int i, j;
	tw_timer_wheel_slot_t *ts;
	TWT (tw_timer) * head, *t;
	u32 next_index;

	for (i = 0; i < TW_TIMER_WHEELS; i++)
	{
	for (j = 0; j < TW_SLOTS_PER_RING; j++)
	{
	ts = &tw->w[i][j];
	head = pool_elt_at_index (tw->timers, ts->head_index);
	next_index = head->next;

	while (next_index != ts->head_index)
	{
	t = pool_elt_at_index (tw->timers, next_index);
	next_index = t->next;
	pool_put (tw->timers, t);
	}
	pool_put (tw->timers, head);
	}
	}
	memset (tw, 0, sizeof (*tw));
	}

	/**
	* @brief Advance a tw timer wheel. Calls the expired timer callback
	* as needed. This routine should be called once every timer_interval seconds
	* @param tw_timer_wheel_t * tw timer wheel template instance pointer
	* @param f64 now the current time, e.g. from vlib_time_now(vm)
	*/
	u32 TW (tw_timer_expire_timers) (TWT (tw_timer_wheel) * tw, f64 now)
	{
	u32 nticks, i;
	tw_timer_wheel_slot_t *ts;
	TWT (tw_timer) * t, *head;
	u32 fast_wheel_index;
	u32 next_index;
	u32 nexpirations, total_nexpirations;
	#if TW_TIMER_WHEELS > 1
	u32 slow_wheel_index;
	#endif

	/* Shouldn't happen */
	if (PREDICT_FALSE (now < tw->next_run_time))
	return 0;

	/* Number of ticks which have occurred */
	nticks = tw->ticks_per_second * (now - tw->last_run_time);
	if (nticks == 0)
	return 0;

	/* Remember when we ran, compute next runtime */
	tw->next_run_time = (now + tw->timer_interval);

	total_nexpirations = 0;
	for (i = 0; i < nticks; i++)
	{
	fast_wheel_index = tw->current_index[TW_TIMER_RING_FAST];

	/*
	* If we've been around the fast ring once,
	* process one slot in the slow ring before we handle
	* the fast ring.
	*/
	if (PREDICT_FALSE (fast_wheel_index == TW_SLOTS_PER_RING))
	{
	fast_wheel_index = tw->current_index[TW_TIMER_RING_FAST] = 0;

	#if TW_TIMER_WHEELS > 1
	tw->current_index[TW_TIMER_RING_SLOW]++;
	tw->current_index[TW_TIMER_RING_SLOW] %= TW_SLOTS_PER_RING;
	slow_wheel_index = tw->current_index[TW_TIMER_RING_SLOW];

	ts = &tw->w[TW_TIMER_RING_SLOW][slow_wheel_index];

	head = pool_elt_at_index (tw->timers, ts->head_index);
	next_index = head->next;

	/* Make slot empty */
	head->next = head->prev = ts->head_index;

	/* traverse slot, deal timers into fast ring */
	while (next_index != head - tw->timers)
	{
	t = pool_elt_at_index (tw->timers, next_index);
	next_index = t->next;

	/* Remove from slow ring slot (hammer) */
	t->next = t->prev = ~0;
	ASSERT (t->fast_ring_offset < TW_SLOTS_PER_RING);
	/* Add to fast ring */
	ts = &tw->w[TW_TIMER_RING_FAST][t->fast_ring_offset];
	timer_addhead (tw->timers, ts->head_index, t - tw->timers);
	}
	#endif
	}

	/* Handle the fast ring */
	vec_reset_length (tw->expired_timer_handles);

	ts = &tw->w[TW_TIMER_RING_FAST][fast_wheel_index];

	head = pool_elt_at_index (tw->timers, ts->head_index);
	next_index = head->next;

	/* Make slot empty */
	head->next = head->prev = ts->head_index;

	/* Construct vector of expired timer handles to give the user */
	while (next_index != ts->head_index)
	{
	t = pool_elt_at_index (tw->timers, next_index);
	next_index = t->next;
	vec_add1 (tw->expired_timer_handles, t->user_handle);
	pool_put (tw->timers, t);
	}

	/* If any timers expired, tell the user */
	nexpirations = vec_len (tw->expired_timer_handles);
	if (nexpirations)
	{
	tw->expired_timer_callback (tw->expired_timer_handles);
	total_nexpirations += nexpirations;
	}
	tw->current_index[TW_TIMER_RING_FAST]++;
	tw->current_tick++;

	if (total_nexpirations >= tw->max_expirations)
	break;
	}

	tw->last_run_time += i * tw->timer_interval;
	return total_nexpirations;
	}

	/*
	* fd.io coding-style-patch-verification: ON
	*
	* Local Variables:
	* eval: (c-set-style "gnu")
	* End:
	*/