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src/share/vm/utilities/yieldingWorkgroup.hpp@a1980da045cc (annotated)

src/share/vm/utilities/yieldingWorkgroup.hpp

Fri, 07 Nov 2008 09:29:38 -0800

author

kvn

date

Fri, 07 Nov 2008 09:29:38 -0800

changeset 855

a1980da045cc

parent 777

37f87013dfd8

child 1907

c18cbe5936b8

permissions

-rw-r--r--

6462850: generate biased locking code in C2 ideal graph
Summary: Inline biased locking code in C2 ideal graph during macro nodes expansion
Reviewed-by: never

duke@435	1	/*
duke@435	2	* Copyright 2005 Sun Microsystems, Inc. All Rights Reserved.
duke@435	3	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@435	4	*
duke@435	5	* This code is free software; you can redistribute it and/or modify it
duke@435	6	* under the terms of the GNU General Public License version 2 only, as
duke@435	7	* published by the Free Software Foundation.
duke@435	8	*
duke@435	9	* This code is distributed in the hope that it will be useful, but WITHOUT
duke@435	10	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@435	11	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
duke@435	12	* version 2 for more details (a copy is included in the LICENSE file that
duke@435	13	* accompanied this code).
duke@435	14	*
duke@435	15	* You should have received a copy of the GNU General Public License version
duke@435	16	* 2 along with this work; if not, write to the Free Software Foundation,
duke@435	17	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@435	18	*
duke@435	19	* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
duke@435	20	* CA 95054 USA or visit www.sun.com if you need additional information or
duke@435	21	* have any questions.
duke@435	22	*
duke@435	23	*/
duke@435	24
duke@435	25
duke@435	26	// Forward declarations
duke@435	27	class YieldingFlexibleWorkGang;
duke@435	28
duke@435	29	// Status of tasks
duke@435	30	enum Status {
duke@435	31	INACTIVE,
duke@435	32	ACTIVE,
duke@435	33	YIELDING,
duke@435	34	YIELDED,
duke@435	35	ABORTING,
duke@435	36	ABORTED,
duke@435	37	COMPLETING,
duke@435	38	COMPLETED
duke@435	39	};
duke@435	40
duke@435	41	// Class YieldingFlexibleGangWorker:
duke@435	42	// Several instances of this class run in parallel as workers for a gang.
duke@435	43	class YieldingFlexibleGangWorker: public GangWorker {
duke@435	44	public:
duke@435	45	// Ctor
duke@435	46	YieldingFlexibleGangWorker(AbstractWorkGang* gang, int id) :
duke@435	47	GangWorker(gang, id) { }
duke@435	48
duke@435	49	public:
duke@435	50	YieldingFlexibleWorkGang* yf_gang() const
duke@435	51	{ return (YieldingFlexibleWorkGang*)gang(); }
duke@435	52
duke@435	53	protected: // Override from parent class
duke@435	54	virtual void loop();
duke@435	55	};
duke@435	56
duke@435	57	// An abstract task to be worked on by a flexible work gang,
duke@435	58	// and where the workers will periodically yield, usually
duke@435	59	// in response to some condition that is signalled by means
duke@435	60	// that are specific to the task at hand.
duke@435	61	// You subclass this to supply your own work() method.
duke@435	62	// A second feature of this kind of work gang is that
duke@435	63	// it allows for the signalling of certain exceptional
duke@435	64	// conditions that may be encountered during the performance
duke@435	65	// of the task and that may require the task at hand to be
duke@435	66	// `aborted' forthwith. Finally, these gangs are `flexible'
duke@435	67	// in that they can operate at partial capacity with some
duke@435	68	// gang workers waiting on the bench; in other words, the
duke@435	69	// size of the active worker pool can flex (up to an apriori
duke@435	70	// maximum) in response to task requests at certain points.
duke@435	71	// The last part (the flexible part) has not yet been fully
duke@435	72	// fleshed out and is a work in progress.
duke@435	73	class YieldingFlexibleGangTask: public AbstractGangTask {
duke@435	74	Status _status;
duke@435	75	YieldingFlexibleWorkGang* _gang;
duke@435	76	int _actual_size; // size of gang obtained
duke@435	77
duke@435	78	protected:
duke@435	79	int _requested_size; // size of gang requested
duke@435	80
duke@435	81	// Constructor and desctructor: only construct subclasses.
duke@435	82	YieldingFlexibleGangTask(const char* name): AbstractGangTask(name),
duke@435	83	_status(INACTIVE),
duke@435	84	_gang(NULL),
duke@435	85	_requested_size(0) { }
duke@435	86
duke@435	87	virtual ~YieldingFlexibleGangTask() { }
duke@435	88
duke@435	89	friend class YieldingFlexibleWorkGang;
duke@435	90	friend class YieldingFlexibleGangWorker;
duke@435	91	NOT_PRODUCT(virtual bool is_YieldingFlexibleGang_task() const {
duke@435	92	return true;
duke@435	93	})
duke@435	94
duke@435	95	void set_status(Status s) {
duke@435	96	_status = s;
duke@435	97	}
duke@435	98	YieldingFlexibleWorkGang* gang() {
duke@435	99	return _gang;
duke@435	100	}
duke@435	101	void set_gang(YieldingFlexibleWorkGang* gang) {
duke@435	102	assert(_gang == NULL || gang == NULL, "Clobber without intermediate reset?");
duke@435	103	_gang = gang;
duke@435	104	}
duke@435	105
duke@435	106	public:
duke@435	107	// The abstract work method.
duke@435	108	// The argument tells you which member of the gang you are.
duke@435	109	virtual void work(int i) = 0;
duke@435	110
duke@435	111	// Subclasses should call the parent's yield() method
duke@435	112	// after having done any work specific to the subclass.
duke@435	113	virtual void yield();
duke@435	114
duke@435	115	// An abstract method supplied by
duke@435	116	// a concrete sub-class which is used by the coordinator
duke@435	117	// to do any "central yielding" work.
duke@435	118	virtual void coordinator_yield() = 0;
duke@435	119
duke@435	120	// Subclasses should call the parent's abort() method
duke@435	121	// after having done any work specific to the sunbclass.
duke@435	122	virtual void abort();
duke@435	123
duke@435	124	Status status() const { return _status; }
duke@435	125	bool yielded() const { return _status == YIELDED; }
duke@435	126	bool completed() const { return _status == COMPLETED; }
duke@435	127	bool aborted() const { return _status == ABORTED; }
duke@435	128	bool active() const { return _status == ACTIVE; }
duke@435	129
duke@435	130	int requested_size() const { return _requested_size; }
duke@435	131	int actual_size() const { return _actual_size; }
duke@435	132
duke@435	133	void set_requested_size(int sz) { _requested_size = sz; }
duke@435	134	void set_actual_size(int sz) { _actual_size = sz; }
duke@435	135	};
duke@435	136
duke@435	137	// Class YieldingWorkGang: A subclass of WorkGang.
duke@435	138	// In particular, a YieldingWorkGang is made up of
duke@435	139	// YieldingGangWorkers, and provides infrastructure
duke@435	140	// supporting yielding to the "GangOverseer",
duke@435	141	// being the thread that orchestrates the WorkGang via run_task().
duke@435	142	class YieldingFlexibleWorkGang: public AbstractWorkGang {
duke@435	143	// Here's the public interface to this class.
duke@435	144	public:
duke@435	145	// Constructor and destructor.
ysr@777	146	YieldingFlexibleWorkGang(const char* name, int workers,
ysr@777	147	bool are_GC_task_threads);
duke@435	148
duke@435	149	YieldingFlexibleGangTask* yielding_task() const {
duke@435	150	assert(task() == NULL || task()->is_YieldingFlexibleGang_task(),
duke@435	151	"Incorrect cast");
duke@435	152	return (YieldingFlexibleGangTask*)task();
duke@435	153	}
duke@435	154	// Run a task; returns when the task is done, or the workers yield,
duke@435	155	// or the task is aborted, or the work gang is terminated via stop().
duke@435	156	// A task that has been yielded can be continued via this same interface
duke@435	157	// by using the same task repeatedly as the argument to the call.
duke@435	158	// It is expected that the YieldingFlexibleGangTask carries the appropriate
duke@435	159	// continuation information used by workers to continue the task
duke@435	160	// from its last yield point. Thus, a completed task will return
duke@435	161	// immediately with no actual work having been done by the workers.
duke@435	162	void run_task(AbstractGangTask* task) {
duke@435	163	guarantee(false, "Use start_task instead");
duke@435	164	}
duke@435	165	void start_task(YieldingFlexibleGangTask* new_task);
duke@435	166	void continue_task(YieldingFlexibleGangTask* gang_task);
duke@435	167
duke@435	168	// Abort a currently running task, if any; returns when all the workers
duke@435	169	// have stopped working on the current task and have returned to their
duke@435	170	// waiting stations.
duke@435	171	void abort_task();
duke@435	172
duke@435	173	// Yield: workers wait at their current working stations
duke@435	174	// until signalled to proceed by the overseer.
duke@435	175	void yield();
duke@435	176
duke@435	177	// Abort: workers are expected to return to their waiting
duke@435	178	// stations, whence they are ready for the next task dispatched
duke@435	179	// by the overseer.
duke@435	180	void abort();
duke@435	181
duke@435	182	private:
duke@435	183	// The currently active workers in this gang.
duke@435	184	// This is a number that is dynamically adjusted by
duke@435	185	// the run_task() method at each subsequent invocation,
duke@435	186	// using data in the YieldingFlexibleGangTask.
duke@435	187	int _active_workers;
duke@435	188	int _yielded_workers;
duke@435	189	void wait_for_gang();
duke@435	190
duke@435	191	public:
duke@435	192	// Accessors for fields
duke@435	193	int active_workers() const {
duke@435	194	return _active_workers;
duke@435	195	}
duke@435	196
duke@435	197	int yielded_workers() const {
duke@435	198	return _yielded_workers;
duke@435	199	}
duke@435	200
duke@435	201	private:
duke@435	202	friend class YieldingFlexibleGangWorker;
duke@435	203	void reset(); // NYI
duke@435	204	};