Multiple revisions 399887,400138,400178,400180-400181

........
  r399887 | dlee | 2013-09-26 10:41:47 -0500 (Thu, 26 Sep 2013) | 1 line
  
  Minor performance bump by not allocate manager variable struct if we don't need it
........
  r400138 | dlee | 2013-09-30 10:24:00 -0500 (Mon, 30 Sep 2013) | 23 lines
  
  Stasis performance improvements
  
  This patch addresses several performance problems that were found in
  the initial performance testing of Asterisk 12.
  
  The Stasis dispatch object was allocated as an AO2 object, even though
  it has a very confined lifecycle. This was replaced with a straight
  ast_malloc().
  
  The Stasis message router was spending an inordinate amount of time
  searching hash tables. In this case, most of our routers had 6 or
  fewer routes in them to begin with. This was replaced with an array
  that's searched linearly for the route.
  
  We more heavily rely on AO2 objects in Asterisk 12, and the memset()
  in ao2_ref() actually became noticeable on the profile. This was
  #ifdef'ed to only run when AO2_DEBUG was enabled.
  
  After being misled by an erroneous comment in taskprocessor.c during
  profiling, the wrong comment was removed.
  
  Review: https://reviewboard.asterisk.org/r/2873/
........
  r400178 | dlee | 2013-09-30 13:26:27 -0500 (Mon, 30 Sep 2013) | 24 lines
  
  Taskprocessor optimization; switch Stasis to use taskprocessors
  
  This patch optimizes taskprocessor to use a semaphore for signaling,
  which the OS can do a better job at managing contention and waiting
  that we can with a mutex and condition.
  
  The taskprocessor execution was also slightly optimized to reduce the
  number of locks taken.
  
  The only observable difference in the taskprocessor implementation is
  that when the final reference to the taskprocessor goes away, it will
  execute all tasks to completion instead of discarding the unexecuted
  tasks.
  
  For systems where unnamed semaphores are not supported, a really
  simple semaphore implementation is provided. (Which gives identical
  performance as the original taskprocessor implementation).
  
  The way we ended up implementing Stasis caused the threadpool to be a
  burden instead of a boost to performance. This was switched to just
  use taskprocessors directly for subscriptions.
  
  Review: https://reviewboard.asterisk.org/r/2881/
........
  r400180 | dlee | 2013-09-30 13:39:34 -0500 (Mon, 30 Sep 2013) | 28 lines
  
  Optimize how Stasis forwards are dispatched
  
  This patch optimizes how forwards are dispatched in Stasis.
  
  Originally, forwards were dispatched as subscriptions that are invoked
  on the publishing thread. This did not account for the vast number of
  forwards we would end up having in the system, and the amount of work it
  would take to walk though the forward subscriptions.
  
  This patch modifies Stasis so that rather than walking the tree of
  forwards on every dispatch, when forwards and subscriptions are changed,
  the subscriber list for every topic in the tree is changed.
  
  This has a couple of benefits. First, this reduces the workload of
  dispatching messages. It also reduces contention when dispatching to
  different topics that happen to forward to the same aggregation topic
  (as happens with all of the channel, bridge and endpoint topics).
  
  Since forwards are no longer subscriptions, the bulk of this patch is
  simply changing stasis_subscription objects to stasis_forward objects
  (which, admittedly, I should have done in the first place.)
  
  Since this required me to yet again put in a growing array, I finally
  abstracted that out into a set of ast_vector macros in
  asterisk/vector.h.
  
  Review: https://reviewboard.asterisk.org/r/2883/
........
  r400181 | dlee | 2013-09-30 13:48:57 -0500 (Mon, 30 Sep 2013) | 28 lines
  
  Remove dispatch object allocation from Stasis publishing
  
  While looking for areas for performance improvement, I realized that an
  unused feature in Stasis was negatively impacting performance.
  
  When a message is sent to a subscriber, a dispatch object is allocated
  for the dispatch, containing the topic the message was published to, the
  subscriber the message is being sent to, and the message itself.
  
  The topic is actually unused by any subscriber in Asterisk today. And
  the subscriber is associated with the taskprocessor the message is being
  dispatched to.
  
  First, this patch removes the unused topic parameter from Stasis
  subscription callbacks.
  
  Second, this patch introduces the concept of taskprocessor local data,
  data that may be set on a taskprocessor and provided along with the data
  pointer when a task is pushed using the ast_taskprocessor_push_local()
  call. This allows the task to have both data specific to that
  taskprocessor, in addition to data specific to that invocation.
  
  With those two changes, the dispatch object can be removed completely,
  and the message is simply refcounted and sent directly to the
  taskprocessor.
  
  Review: https://reviewboard.asterisk.org/r/2884/
........

Merged revisions 399887,400138,400178,400180-400181 from http://svn.asterisk.org/svn/asterisk/branches/12


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@400186 65c4cc65-6c06-0410-ace0-fbb531ad65f3

1 files changed, 164 insertions, 70 deletions

diff --git a/main/taskprocessor.c b/main/taskprocessor.c
index a8d1c80f9..189219d66 100644
--- a/main/taskprocessor.c
+++ b/main/taskprocessor.c
@@ -37,6 +37,7 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
 #include "asterisk/astobj2.h"
 #include "asterisk/cli.h"
 #include "asterisk/taskprocessor.h"
+#include "asterisk/sem.h"
 
 /*!
  * \brief tps_task structure is queued to a taskprocessor
@@ -47,11 +48,15 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
  */
 struct tps_task {
 	/*! \brief The execute() task callback function pointer */
-	int (*execute)(void *datap);
+	union {
+		int (*execute)(void *datap);
+		int (*execute_local)(struct ast_taskprocessor_local *local);
+	} callback;
 	/*! \brief The data pointer for the task execute() function */
 	void *datap;
 	/*! \brief AST_LIST_ENTRY overhead */
 	AST_LIST_ENTRY(tps_task) list;
+	unsigned int wants_local:1;
 };
 
 /*! \brief tps_taskprocessor_stats maintain statistics for a taskprocessor. */
@@ -68,6 +73,7 @@ struct ast_taskprocessor {
 	const char *name;
 	/*! \brief Taskprocessor statistics */
 	struct tps_taskprocessor_stats *stats;
+	void *local_data;
 	/*! \brief Taskprocessor current queue size */
 	long tps_queue_size;
 	/*! \brief Taskprocessor queue */
@@ -113,9 +119,6 @@ static int tps_hash_cb(const void *obj, const int flags);
 /*! \brief The astobj2 compare callback for taskprocessors */
 static int tps_cmp_cb(void *obj, void *arg, int flags);
 
-/*! \brief The task processing function executed by a taskprocessor */
-static void *tps_processing_function(void *data);
-
 /*! \brief Destroy the taskprocessor when its refcount reaches zero */
 static void tps_taskprocessor_destroy(void *tps);
 
@@ -138,47 +141,56 @@ static struct ast_cli_entry taskprocessor_clis[] = {
 
 struct default_taskprocessor_listener_pvt {
 	pthread_t poll_thread;
-	ast_mutex_t lock;
-	ast_cond_t cond;
-	int wake_up;
 	int dead;
+	struct ast_sem sem;
 };
 
-
-static void default_tps_wake_up(struct default_taskprocessor_listener_pvt *pvt, int should_die)
+static void default_listener_pvt_destroy(struct default_taskprocessor_listener_pvt *pvt)
 {
-	SCOPED_MUTEX(lock, &pvt->lock);
-	pvt->wake_up = 1;
-	pvt->dead = should_die;
-	ast_cond_signal(&pvt->cond);
+	ast_assert(pvt->dead);
+	ast_sem_destroy(&pvt->sem);
+	ast_free(pvt);
 }
 
-static int default_tps_idle(struct default_taskprocessor_listener_pvt *pvt)
+static void default_listener_pvt_dtor(struct ast_taskprocessor_listener *listener)
 {
-	SCOPED_MUTEX(lock, &pvt->lock);
-	while (!pvt->wake_up) {
-		ast_cond_wait(&pvt->cond, lock);
-	}
-	pvt->wake_up = 0;
-	return pvt->dead;
+	struct default_taskprocessor_listener_pvt *pvt = listener->user_data;
+
+	default_listener_pvt_destroy(pvt);
+
+	listener->user_data = NULL;
 }
 
 /*!
  * \brief Function that processes tasks in the taskprocessor
  * \internal
  */
-static void *tps_processing_function(void *data)
+static void *default_tps_processing_function(void *data)
 {
 	struct ast_taskprocessor_listener *listener = data;
 	struct ast_taskprocessor *tps = listener->tps;
 	struct default_taskprocessor_listener_pvt *pvt = listener->user_data;
-	int dead = 0;
-
-	while (!dead) {
-		if (!ast_taskprocessor_execute(tps)) {
-			dead = default_tps_idle(pvt);
+	int sem_value;
+	int res;
+
+	while (!pvt->dead) {
+		res = ast_sem_wait(&pvt->sem);
+		if (res != 0 && errno != EINTR) {
+			ast_log(LOG_ERROR, "ast_sem_wait(): %s\n",
+				strerror(errno));
+			/* Just give up */
+			break;
 		}
+		ast_taskprocessor_execute(tps);
 	}
+
+	/* No posting to a dead taskprocessor! */
+	res = ast_sem_getvalue(&pvt->sem, &sem_value);
+	ast_assert(res == 0 && sem_value == 0);
+
+	/* Free the shutdown reference (see default_listener_shutdown) */
+	ao2_t_ref(listener->tps, -1, "tps-shutdown");
+
 	return NULL;
 }
 
@@ -186,7 +198,7 @@ static int default_listener_start(struct ast_taskprocessor_listener *listener)
 {
 	struct default_taskprocessor_listener_pvt *pvt = listener->user_data;
 
-	if (ast_pthread_create(&pvt->poll_thread, NULL, tps_processing_function, listener)) {
+	if (ast_pthread_create(&pvt->poll_thread, NULL, default_tps_processing_function, listener)) {
 		return -1;
 	}
 
@@ -197,33 +209,50 @@ static void default_task_pushed(struct ast_taskprocessor_listener *listener, int
 {
 	struct default_taskprocessor_listener_pvt *pvt = listener->user_data;
 
-	ast_assert(!pvt->dead);
-
-	if (was_empty) {
-		default_tps_wake_up(pvt, 0);
+	if (ast_sem_post(&pvt->sem) != 0) {
+		ast_log(LOG_ERROR, "Failed to notify of enqueued task: %s\n",
+			strerror(errno));
 	}
 }
 
-static void default_listener_pvt_destroy(struct default_taskprocessor_listener_pvt *pvt)
+static int default_listener_die(void *data)
 {
-	ast_mutex_destroy(&pvt->lock);
-	ast_cond_destroy(&pvt->cond);
-	ast_free(pvt);
+	struct default_taskprocessor_listener_pvt *pvt = data;
+	pvt->dead = 1;
+	return 0;
 }
 
 static void default_listener_shutdown(struct ast_taskprocessor_listener *listener)
 {
 	struct default_taskprocessor_listener_pvt *pvt = listener->user_data;
-	default_tps_wake_up(pvt, 1);
-	pthread_join(pvt->poll_thread, NULL);
+	int res;
+
+	/* Hold a reference during shutdown */
+	ao2_t_ref(listener->tps, +1, "tps-shutdown");
+
+	ast_taskprocessor_push(listener->tps, default_listener_die, pvt);
+
+	if (pthread_self() == pvt->poll_thread) {
+		res = pthread_detach(pvt->poll_thread);
+		if (res != 0) {
+			ast_log(LOG_ERROR, "pthread_detach(): %s\n",
+				strerror(errno));
+		}
+	} else {
+		res = pthread_join(pvt->poll_thread, NULL);
+		if (res != 0) {
+			ast_log(LOG_ERROR, "pthread_join(): %s\n",
+				strerror(errno));
+		}
+	}
 	pvt->poll_thread = AST_PTHREADT_NULL;
-	default_listener_pvt_destroy(pvt);
 }
 
 static const struct ast_taskprocessor_listener_callbacks default_listener_callbacks = {
 	.start = default_listener_start,
 	.task_pushed = default_task_pushed,
 	.shutdown = default_listener_shutdown,
+	.dtor = default_listener_pvt_dtor,
 };
 
 /*!
@@ -258,19 +287,48 @@ int ast_tps_init(void)
 static struct tps_task *tps_task_alloc(int (*task_exe)(void *datap), void *datap)
 {
 	struct tps_task *t;
-	if ((t = ast_calloc(1, sizeof(*t)))) {
-		t->execute = task_exe;
-		t->datap = datap;
+	if (!task_exe) {
+		ast_log(LOG_ERROR, "task_exe is NULL!\n");
+		return NULL;
+	}
+
+	t = ast_calloc(1, sizeof(*t));
+	if (!t) {
+		ast_log(LOG_ERROR, "failed to allocate task!\n");
+		return NULL;
+	}
+
+	t->callback.execute = task_exe;
+	t->datap = datap;
+
+	return t;
+}
+
+static struct tps_task *tps_task_alloc_local(int (*task_exe)(struct ast_taskprocessor_local *local), void *datap)
+{
+	struct tps_task *t;
+	if (!task_exe) {
+		ast_log(LOG_ERROR, "task_exe is NULL!\n");
+		return NULL;
+	}
+
+	t = ast_calloc(1, sizeof(*t));
+	if (!t) {
+		ast_log(LOG_ERROR, "failed to allocate task!\n");
+		return NULL;
 	}
+
+	t->callback.execute_local = task_exe;
+	t->datap = datap;
+	t->wants_local = 1;
+
 	return t;
 }
 
 /* release task resources */
 static void *tps_task_free(struct tps_task *task)
 {
-	if (task) {
-		ast_free(task);
-	}
+	ast_free(task);
 	return NULL;
 }
 
@@ -425,16 +483,10 @@ static void tps_taskprocessor_destroy(void *tps)
 	}
 	ast_debug(1, "destroying taskprocessor '%s'\n", t->name);
 	/* free it */
-	if (t->stats) {
-		ast_free(t->stats);
-		t->stats = NULL;
-	}
+	ast_free(t->stats);
+	t->stats = NULL;
 	ast_free((char *) t->name);
 	if (t->listener) {
-		/* This code should not be reached since the listener
-		 * should have been destroyed before the taskprocessor could
-		 * be destroyed
-		 */
 		ao2_ref(t->listener, -1);
 		t->listener = NULL;
 	}
@@ -447,7 +499,6 @@ static void tps_taskprocessor_destroy(void *tps)
 static struct tps_task *tps_taskprocessor_pop(struct ast_taskprocessor *tps)
 {
 	struct tps_task *task;
-	SCOPED_AO2LOCK(lock, tps);
 
 	if ((task = AST_LIST_REMOVE_HEAD(&tps->tps_queue, list))) {
 		tps->tps_queue_size--;
@@ -476,10 +527,21 @@ static void listener_shutdown(struct ast_taskprocessor_listener *listener)
 	ao2_ref(listener->tps, -1);
 }
 
+static void taskprocessor_listener_dtor(void *obj)
+{
+	struct ast_taskprocessor_listener *listener = obj;
+
+	if (listener->callbacks->dtor) {
+		listener->callbacks->dtor(listener);
+	}
+}
+
 struct ast_taskprocessor_listener *ast_taskprocessor_listener_alloc(const struct ast_taskprocessor_listener_callbacks *callbacks, void *user_data)
 {
 	RAII_VAR(struct ast_taskprocessor_listener *, listener,
-			ao2_alloc(sizeof(*listener), NULL), ao2_cleanup);
+			NULL, ao2_cleanup);
+
+	listener = ao2_alloc(sizeof(*listener), taskprocessor_listener_dtor);
 
 	if (!listener) {
 		return NULL;
@@ -510,9 +572,12 @@ static void *default_listener_pvt_alloc(void)
 	if (!pvt) {
 		return NULL;
 	}
-	ast_cond_init(&pvt->cond, NULL);
-	ast_mutex_init(&pvt->lock);
 	pvt->poll_thread = AST_PTHREADT_NULL;
+	if (ast_sem_init(&pvt->sem, 0, 0) != 0) {
+		ast_log(LOG_ERROR, "ast_sem_init(): %s\n", strerror(errno));
+		ast_free(pvt);
+		return NULL;
+	}
 	return pvt;
 }
 
@@ -594,7 +659,6 @@ struct ast_taskprocessor *ast_taskprocessor_get(const char *name, enum ast_tps_o
 
 	p = __allocate_taskprocessor(name, listener);
 	if (!p) {
-		default_listener_pvt_destroy(pvt);
 		ao2_ref(listener, -1);
 		return NULL;
 	}
@@ -615,6 +679,13 @@ struct ast_taskprocessor *ast_taskprocessor_create_with_listener(const char *nam
 	return __allocate_taskprocessor(name, listener);
 }
 
+void ast_taskprocessor_set_local(struct ast_taskprocessor *tps,
+	void *local_data)
+{
+	SCOPED_AO2LOCK(lock, tps);
+	tps->local_data = local_data;
+}
+
 /* decrement the taskprocessor reference count and unlink from the container if necessary */
 void *ast_taskprocessor_unreference(struct ast_taskprocessor *tps)
 {
@@ -636,20 +707,21 @@ void *ast_taskprocessor_unreference(struct ast_taskprocessor *tps)
 }
 
 /* push the task into the taskprocessor queue */
-int ast_taskprocessor_push(struct ast_taskprocessor *tps, int (*task_exe)(void *datap), void *datap)
+static int taskprocessor_push(struct ast_taskprocessor *tps, struct tps_task *t)
 {
-	struct tps_task *t;
 	int previous_size;
 	int was_empty;
 
-	if (!tps || !task_exe) {
-		ast_log(LOG_ERROR, "%s is missing!!\n", (tps) ? "task callback" : "taskprocessor");
+	if (!tps) {
+		ast_log(LOG_ERROR, "tps is NULL!\n");
 		return -1;
 	}
-	if (!(t = tps_task_alloc(task_exe, datap))) {
-		ast_log(LOG_ERROR, "failed to allocate task!  Can't push to '%s'\n", tps->name);
+
+	if (!t) {
+		ast_log(LOG_ERROR, "t is NULL!\n");
 		return -1;
 	}
+
 	ao2_lock(tps);
 	AST_LIST_INSERT_TAIL(&tps->tps_queue, t, list);
 	previous_size = tps->tps_queue_size++;
@@ -660,21 +732,43 @@ int ast_taskprocessor_push(struct ast_taskprocessor *tps, int (*task_exe)(void *
 	return 0;
 }
 
+int ast_taskprocessor_push(struct ast_taskprocessor *tps, int (*task_exe)(void *datap), void *datap)
+{
+	return taskprocessor_push(tps, tps_task_alloc(task_exe, datap));
+}
+
+int ast_taskprocessor_push_local(struct ast_taskprocessor *tps, int (*task_exe)(struct ast_taskprocessor_local *datap), void *datap)
+{
+	return taskprocessor_push(tps, tps_task_alloc_local(task_exe, datap));
+}
+
 int ast_taskprocessor_execute(struct ast_taskprocessor *tps)
 {
+	struct ast_taskprocessor_local local;
 	struct tps_task *t;
 	int size;
 
 	ao2_lock(tps);
+	t = tps_taskprocessor_pop(tps);
+	if (!t) {
+		ao2_unlock(tps);
+		return 0;
+	}
+
 	tps->executing = 1;
-	ao2_unlock(tps);
 
-	t = tps_taskprocessor_pop(tps);
+	if (t->wants_local) {
+		local.local_data = tps->local_data;
+		local.data = t->datap;
+	}
+	ao2_unlock(tps);
 
-	if (t) {
-		t->execute(t->datap);
-		tps_task_free(t);
+	if (t->wants_local) {
+		t->callback.execute_local(&local);
+	} else {
+		t->callback.execute(t->datap);
 	}
+	tps_task_free(t);
 
 	ao2_lock(tps);
 	/* We need to check size in the same critical section where we reset the
@@ -684,7 +778,7 @@ int ast_taskprocessor_execute(struct ast_taskprocessor *tps)
 	tps->executing = 0;
 	size = tps_taskprocessor_depth(tps);
 	/* If we executed a task, bump the stats */
-	if (t && tps->stats) {
+	if (tps->stats) {
 		tps->stats->_tasks_processed_count++;
 		if (size > tps->stats->max_qsize) {
 			tps->stats->max_qsize = size;
@@ -693,7 +787,7 @@ int ast_taskprocessor_execute(struct ast_taskprocessor *tps)
 	ao2_unlock(tps);
 
 	/* If we executed a task, check for the transition to empty */
-	if (t && size == 0 && tps->listener->callbacks->emptied) {
+	if (size == 0 && tps->listener->callbacks->emptied) {
 		tps->listener->callbacks->emptied(tps->listener);
 	}
 	return size > 0;