/*
- Copyright 2005-2011 Intel Corporation. All Rights Reserved.
-
- This file is part of Threading Building Blocks.
-
- Threading Building Blocks is free software; you can redistribute it
- and/or modify it under the terms of the GNU General Public License
- version 2 as published by the Free Software Foundation.
-
- Threading Building Blocks is distributed in the hope that it will be
- useful, but WITHOUT ANY WARRANTY; without even the implied warranty
- of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- GNU General Public License for more details.
-
- You should have received a copy of the GNU General Public License
- along with Threading Building Blocks; if not, write to the Free Software
- Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
-
- As a special exception, you may use this file as part of a free software
- library without restriction. Specifically, if other files instantiate
- templates or use macros or inline functions from this file, or you compile
- this file and link it with other files to produce an executable, this
- file does not by itself cause the resulting executable to be covered by
- the GNU General Public License. This exception does not however
- invalidate any other reasons why the executable file might be covered by
- the GNU General Public License.
+ Copyright 2005-2014 Intel Corporation. All Rights Reserved.
+
+ This file is part of Threading Building Blocks. Threading Building Blocks is free software;
+ you can redistribute it and/or modify it under the terms of the GNU General Public License
+ version 2 as published by the Free Software Foundation. Threading Building Blocks is
+ distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the
+ implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ See the GNU General Public License for more details. You should have received a copy of
+ the GNU General Public License along with Threading Building Blocks; if not, write to the
+ Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+
+ As a special exception, you may use this file as part of a free software library without
+ restriction. Specifically, if other files instantiate templates or use macros or inline
+ functions from this file, or you compile this file and link it with other files to produce
+ an executable, this file does not by itself cause the resulting executable to be covered
+ by the GNU General Public License. This exception does not however invalidate any other
+ reasons why the executable file might be covered by the GNU General Public License.
*/
#ifndef __TBB_task_scheduler_observer_H
#define __TBB_task_scheduler_observer_H
#include "atomic.h"
+#if __TBB_TASK_ARENA
+#include "task_arena.h"
+#endif //__TBB_TASK_ARENA
#if __TBB_SCHEDULER_OBSERVER
namespace tbb {
-
+namespace interface6 {
+class task_scheduler_observer;
+}
namespace internal {
class observer_proxy;
+class observer_list;
class task_scheduler_observer_v3 {
friend class observer_proxy;
+ friend class observer_list;
+ friend class interface6::task_scheduler_observer;
+
+ //! Pointer to the proxy holding this observer.
+ /** Observers are proxied by the scheduler to maintain persistent lists of them. **/
observer_proxy* my_proxy;
+
+ //! Counter preventing the observer from being destroyed while in use by the scheduler.
+ /** Valid only when observation is on. **/
atomic<intptr_t> my_busy_count;
+
public:
//! Enable or disable observation
+ /** For local observers the method can be used only when the current thread
+ has the task scheduler initialized or is attached to an arena.
+
+ Repeated calls with the same state are no-ops. **/
void __TBB_EXPORTED_METHOD observe( bool state=true );
- //! True if observation is enables; false otherwise.
+ //! Returns true if observation is enabled, false otherwise.
bool is_observing() const {return my_proxy!=NULL;}
//! Construct observer with observation disabled.
- task_scheduler_observer_v3() : my_proxy(NULL) {my_busy_count=0;}
+ task_scheduler_observer_v3() : my_proxy(NULL) { my_busy_count.store<relaxed>(0); }
+
+ //! Entry notification
+ /** Invoked from inside observe(true) call and whenever a worker enters the arena
+ this observer is associated with. If a thread is already in the arena when
+ the observer is activated, the entry notification is called before it
+ executes the first stolen task.
- //! Called by thread before first steal since observation became enabled
+ Obsolete semantics. For global observers it is called by a thread before
+ the first steal since observation became enabled. **/
virtual void on_scheduler_entry( bool /*is_worker*/ ) {}
- //! Called by thread when it no longer takes part in task stealing.
+ //! Exit notification
+ /** Invoked from inside observe(false) call and whenever a worker leaves the
+ arena this observer is associated with.
+
+ Obsolete semantics. For global observers it is called by a thread before
+ the first steal since observation became enabled. **/
virtual void on_scheduler_exit( bool /*is_worker*/ ) {}
- //! Destructor
- virtual ~task_scheduler_observer_v3() {observe(false);}
+ //! Destructor automatically switches observation off if it is enabled.
+ virtual ~task_scheduler_observer_v3() { if(my_proxy) observe(false);}
};
} // namespace internal
-typedef internal::task_scheduler_observer_v3 task_scheduler_observer;
+#if __TBB_ARENA_OBSERVER
+namespace interface6 {
+class task_scheduler_observer : public internal::task_scheduler_observer_v3 {
+ friend class internal::task_scheduler_observer_v3;
+ friend class internal::observer_proxy;
+ friend class internal::observer_list;
+
+ /** Negative numbers with the largest absolute value to minimize probability
+ of coincidence in case of a bug in busy count usage. **/
+ // TODO: take more high bits for version number
+ static const intptr_t v6_trait = (intptr_t)((~(uintptr_t)0 >> 1) + 1);
+
+ //! contains task_arena pointer or tag indicating local or global semantics of the observer
+ intptr_t my_context_tag;
+ enum { global_tag = 0, implicit_tag = 1 };
+
+public:
+ //! Construct local or global observer in inactive state (observation disabled).
+ /** For a local observer entry/exit notifications are invoked whenever a worker
+ thread joins/leaves the arena of the observer's owner thread. If a thread is
+ already in the arena when the observer is activated, the entry notification is
+ called before it executes the first stolen task. **/
+ /** TODO: Obsolete.
+ Global observer semantics is obsolete as it violates master thread isolation
+ guarantees and is not composable. Thus the current default behavior of the
+ constructor is obsolete too and will be changed in one of the future versions
+ of the library. **/
+ task_scheduler_observer( bool local = false ) {
+ my_context_tag = local? implicit_tag : global_tag;
+ }
+
+#if __TBB_TASK_ARENA
+ //! Construct local observer for a given arena in inactive state (observation disabled).
+ /** entry/exit notifications are invoked whenever a thread joins/leaves arena.
+ If a thread is already in the arena when the observer is activated, the entry notification
+ is called before it executes the first stolen task. **/
+ task_scheduler_observer( task_arena & a) {
+ my_context_tag = (intptr_t)&a;
+ }
+#endif //__TBB_TASK_ARENA
+
+ /** Destructor protects instance of the observer from concurrent notification.
+ It is recommended to disable observation before destructor of a derived class starts,
+ otherwise it can lead to concurrent notification callback on partly destroyed object **/
+ virtual ~task_scheduler_observer() { if(my_proxy) observe(false); }
+
+ //! Enable or disable observation
+ /** Warning: concurrent invocations of this method are not safe.
+ Repeated calls with the same state are no-ops. **/
+ void observe( bool state=true ) {
+ if( state && !my_proxy ) {
+ __TBB_ASSERT( !my_busy_count, "Inconsistent state of task_scheduler_observer instance");
+ my_busy_count.store<relaxed>(v6_trait);
+ }
+ internal::task_scheduler_observer_v3::observe(state);
+ }
+
+ //! Return commands for may_sleep()
+ enum { keep_awake = false, allow_sleep = true };
+
+ //! The callback can be invoked by a worker thread before it goes to sleep.
+ /** If it returns false ('keep_awake'), the thread will keep spinning and looking for work.
+ It will not be called for master threads. **/
+ virtual bool may_sleep() { return allow_sleep; }
+};
+
+} //namespace interface6
+using interface6::task_scheduler_observer;
+#else /*__TBB_ARENA_OBSERVER*/
+typedef tbb::internal::task_scheduler_observer_v3 task_scheduler_observer;
+#endif /*__TBB_ARENA_OBSERVER*/
} // namespace tbb
projects / casparcg / blobdiff