--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/share/vm/utilities/workgroup.hpp	Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,345 @@
+/*
+ * Copyright 2002-2007 Sun Microsystems, Inc.  All Rights Reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code 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
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ *
+ */
+
+// Forward declarations of classes defined here
+
+class WorkGang;
+class GangWorker;
+class YieldingFlexibleGangWorker;
+class YieldingFlexibleGangTask;
+class WorkData;
+
+// An abstract task to be worked on by a gang.
+// You subclass this to supply your own work() method
+class AbstractGangTask: public CHeapObj {
+public:
+  // The abstract work method.
+  // The argument tells you which member of the gang you are.
+  virtual void work(int i) = 0;
+
+  // Debugging accessor for the name.
+  const char* name() const PRODUCT_RETURN_(return NULL;);
+  int counter() { return _counter; }
+  void set_counter(int value) { _counter = value; }
+  int *address_of_counter() { return &_counter; }
+
+  // RTTI
+  NOT_PRODUCT(virtual bool is_YieldingFlexibleGang_task() const {
+    return false;
+  })
+
+private:
+  NOT_PRODUCT(const char* _name;)
+  // ??? Should a task have a priority associated with it?
+  // ??? Or can the run method adjust priority as needed?
+  int _counter;
+
+protected:
+  // Constructor and desctructor: only construct subclasses.
+  AbstractGangTask(const char* name) {
+    NOT_PRODUCT(_name = name);
+    _counter = 0;
+  }
+  virtual ~AbstractGangTask() { }
+};
+
+
+// Class AbstractWorkGang:
+// An abstract class representing a gang of workers.
+// You subclass this to supply an implementation of run_task().
+class AbstractWorkGang: public CHeapObj {
+  // Here's the public interface to this class.
+public:
+  // Constructor and destructor.
+  AbstractWorkGang(const char* name, bool are_GC_threads);
+  ~AbstractWorkGang();
+  // Run a task, returns when the task is done (or terminated).
+  virtual void run_task(AbstractGangTask* task) = 0;
+  // Stop and terminate all workers.
+  virtual void stop();
+public:
+  // Debugging.
+  const char* name() const;
+protected:
+  // Initialize only instance data.
+  const bool _are_GC_threads;
+  // Printing support.
+  const char* _name;
+  // The monitor which protects these data,
+  // and notifies of changes in it.
+  Monitor*  _monitor;
+  // The count of the number of workers in the gang.
+  int _total_workers;
+  // Whether the workers should terminate.
+  bool _terminate;
+  // The array of worker threads for this gang.
+  // This is only needed for cleaning up.
+  GangWorker** _gang_workers;
+  // The task for this gang.
+  AbstractGangTask* _task;
+  // A sequence number for the current task.
+  int _sequence_number;
+  // The number of started workers.
+  int _started_workers;
+  // The number of finished workers.
+  int _finished_workers;
+public:
+  // Accessors for fields
+  Monitor* monitor() const {
+    return _monitor;
+  }
+  int total_workers() const {
+    return _total_workers;
+  }
+  bool terminate() const {
+    return _terminate;
+  }
+  GangWorker** gang_workers() const {
+    return _gang_workers;
+  }
+  AbstractGangTask* task() const {
+    return _task;
+  }
+  int sequence_number() const {
+    return _sequence_number;
+  }
+  int started_workers() const {
+    return _started_workers;
+  }
+  int finished_workers() const {
+    return _finished_workers;
+  }
+  bool are_GC_threads() const {
+    return _are_GC_threads;
+  }
+  // Predicates.
+  bool is_idle() const {
+    return (task() == NULL);
+  }
+  // Return the Ith gang worker.
+  GangWorker* gang_worker(int i) const;
+
+  void threads_do(ThreadClosure* tc) const;
+
+  // Printing
+  void print_worker_threads_on(outputStream *st) const;
+  void print_worker_threads() const {
+    print_worker_threads_on(tty);
+  }
+
+protected:
+  friend class GangWorker;
+  friend class YieldingFlexibleGangWorker;
+  // Note activation and deactivation of workers.
+  // These methods should only be called with the mutex held.
+  void internal_worker_poll(WorkData* data) const;
+  void internal_note_start();
+  void internal_note_finish();
+};
+
+class WorkData: public StackObj {
+  // This would be a struct, but I want accessor methods.
+private:
+  bool              _terminate;
+  AbstractGangTask* _task;
+  int               _sequence_number;
+public:
+  // Constructor and destructor
+  WorkData() {
+    _terminate       = false;
+    _task            = NULL;
+    _sequence_number = 0;
+  }
+  ~WorkData() {
+  }
+  // Accessors and modifiers
+  bool terminate()                       const { return _terminate;  }
+  void set_terminate(bool value)               { _terminate = value; }
+  AbstractGangTask* task()               const { return _task; }
+  void set_task(AbstractGangTask* value)       { _task = value; }
+  int sequence_number()                  const { return _sequence_number; }
+  void set_sequence_number(int value)          { _sequence_number = value; }
+
+  YieldingFlexibleGangTask* yf_task()    const {
+    return (YieldingFlexibleGangTask*)_task;
+  }
+};
+
+// Class WorkGang:
+class WorkGang: public AbstractWorkGang {
+public:
+  // Constructor
+  WorkGang(const char* name, int workers, bool are_GC_threads);
+  // Run a task, returns when the task is done (or terminated).
+  virtual void run_task(AbstractGangTask* task);
+};
+
+// Class GangWorker:
+//   Several instances of this class run in parallel as workers for a gang.
+class GangWorker: public WorkerThread {
+public:
+  // Constructors and destructor.
+  GangWorker(AbstractWorkGang* gang, uint id);
+
+  // The only real method: run a task for the gang.
+  virtual void run();
+  // Predicate for Thread
+  virtual bool is_GC_task_thread() const;
+  // Printing
+  void print_on(outputStream* st) const;
+  virtual void print() const { print_on(tty); }
+protected:
+  AbstractWorkGang* _gang;
+
+  virtual void initialize();
+  virtual void loop();
+
+public:
+  AbstractWorkGang* gang() const { return _gang; }
+};
+
+// A class that acts as a synchronisation barrier. Workers enter
+// the barrier and must wait until all other workers have entered
+// before any of them may leave.
+
+class WorkGangBarrierSync : public StackObj {
+protected:
+  Monitor _monitor;
+  int     _n_workers;
+  int     _n_completed;
+
+  Monitor* monitor()       { return &_monitor; }
+  int      n_workers()     { return _n_workers; }
+  int      n_completed()   { return _n_completed; }
+
+  void     inc_completed() { _n_completed++; }
+
+public:
+  WorkGangBarrierSync();
+  WorkGangBarrierSync(int n_workers, const char* name);
+
+  // Set the number of workers that will use the barrier.
+  // Must be called before any of the workers start running.
+  void set_n_workers(int n_workers);
+
+  // Enter the barrier. A worker that enters the barrier will
+  // not be allowed to leave until all other threads have
+  // also entered the barrier.
+  void enter();
+};
+
+// A class to manage claiming of subtasks within a group of tasks.  The
+// subtasks will be identified by integer indices, usually elements of an
+// enumeration type.
+
+class SubTasksDone: public CHeapObj {
+  jint* _tasks;
+  int _n_tasks;
+  int _n_threads;
+  jint _threads_completed;
+#ifdef ASSERT
+  jint _claimed;
+#endif
+
+  // Set all tasks to unclaimed.
+  void clear();
+
+public:
+  // Initializes "this" to a state in which there are "n" tasks to be
+  // processed, none of the which are originally claimed.  The number of
+  // threads doing the tasks is initialized 1.
+  SubTasksDone(int n);
+
+  // True iff the object is in a valid state.
+  bool valid();
+
+  // Set the number of parallel threads doing the tasks to "t".  Can only
+  // be called before tasks start or after they are complete.
+  void set_par_threads(int t);
+
+  // Returns "false" if the task "t" is unclaimed, and ensures that task is
+  // claimed.  The task "t" is required to be within the range of "this".
+  bool is_task_claimed(int t);
+
+  // The calling thread asserts that it has attempted to claim all the
+  // tasks that it will try to claim.  Every thread in the parallel task
+  // must execute this.  (When the last thread does so, the task array is
+  // cleared.)
+  void all_tasks_completed();
+
+  // Destructor.
+  ~SubTasksDone();
+};
+
+// As above, but for sequential tasks, i.e. instead of claiming
+// sub-tasks from a set (possibly an enumeration), claim sub-tasks
+// in sequential order. This is ideal for claiming dynamically
+// partitioned tasks (like striding in the parallel remembered
+// set scanning). Note that unlike the above class this is
+// a stack object - is there any reason for it not to be?
+
+class SequentialSubTasksDone : public StackObj {
+protected:
+  jint _n_tasks;     // Total number of tasks available.
+  jint _n_claimed;   // Number of tasks claimed.
+  jint _n_threads;   // Total number of parallel threads.
+  jint _n_completed; // Number of completed threads.
+
+  void clear();
+
+public:
+  SequentialSubTasksDone() { clear(); }
+  ~SequentialSubTasksDone() {}
+
+  // True iff the object is in a valid state.
+  bool valid();
+
+  // number of tasks
+  jint n_tasks() const { return _n_tasks; }
+
+  // Set the number of parallel threads doing the tasks to t.
+  // Should be called before the task starts but it is safe
+  // to call this once a task is running provided that all
+  // threads agree on the number of threads.
+  void set_par_threads(int t) { _n_threads = t; }
+
+  // Set the number of tasks to be claimed to t. As above,
+  // should be called before the tasks start but it is safe
+  // to call this once a task is running provided all threads
+  // agree on the number of tasks.
+  void set_n_tasks(int t) { _n_tasks = t; }
+
+  // Returns false if the next task in the sequence is unclaimed,
+  // and ensures that it is claimed. Will set t to be the index
+  // of the claimed task in the sequence. Will return true if
+  // the task cannot be claimed and there are none left to claim.
+  bool is_task_claimed(int& t);
+
+  // The calling thread asserts that it has attempted to claim
+  // all the tasks it possibly can in the sequence. Every thread
+  // claiming tasks must promise call this. Returns true if this
+  // is the last thread to complete so that the thread can perform
+  // cleanup if necessary.
+  bool all_tasks_completed();
+};