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src/share/vm/utilities/taskqueue.cpp@9f4457a14b58 (annotated)

src/share/vm/utilities/taskqueue.cpp

Wed, 09 Apr 2008 15:10:22 -0700

author

rasbold

date

Wed, 09 Apr 2008 15:10:22 -0700

changeset 544

9f4457a14b58

parent 435

a61af66fc99e

child 777

37f87013dfd8

permissions

-rw-r--r--

Merge

duke@435	1	/*
duke@435	2	* Copyright 2001-2006 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	# include "incls/_precompiled.incl"
duke@435	26	# include "incls/_taskqueue.cpp.incl"
duke@435	27
duke@435	28	bool TaskQueueSuper::peek() {
duke@435	29	return _bottom != _age.top();
duke@435	30	}
duke@435	31
duke@435	32	int TaskQueueSetSuper::randomParkAndMiller(int *seed0) {
duke@435	33	const int a = 16807;
duke@435	34	const int m = 2147483647;
duke@435	35	const int q = 127773; /* m div a */
duke@435	36	const int r = 2836; /* m mod a */
duke@435	37	assert(sizeof(int) == 4, "I think this relies on that");
duke@435	38	int seed = *seed0;
duke@435	39	int hi = seed / q;
duke@435	40	int lo = seed % q;
duke@435	41	int test = a * lo - r * hi;
duke@435	42	if (test > 0)
duke@435	43	seed = test;
duke@435	44	else
duke@435	45	seed = test + m;
duke@435	46	*seed0 = seed;
duke@435	47	return seed;
duke@435	48	}
duke@435	49
duke@435	50	ParallelTaskTerminator::
duke@435	51	ParallelTaskTerminator(int n_threads, TaskQueueSetSuper* queue_set) :
duke@435	52	_n_threads(n_threads),
duke@435	53	_queue_set(queue_set),
duke@435	54	_offered_termination(0) {}
duke@435	55
duke@435	56	bool ParallelTaskTerminator::peek_in_queue_set() {
duke@435	57	return _queue_set->peek();
duke@435	58	}
duke@435	59
duke@435	60	void ParallelTaskTerminator::yield() {
duke@435	61	os::yield();
duke@435	62	}
duke@435	63
duke@435	64	void ParallelTaskTerminator::sleep(uint millis) {
duke@435	65	os::sleep(Thread::current(), millis, false);
duke@435	66	}
duke@435	67
duke@435	68	bool ParallelTaskTerminator::offer_termination() {
duke@435	69	Atomic::inc(&_offered_termination);
duke@435	70
duke@435	71	juint yield_count = 0;
duke@435	72	while (true) {
duke@435	73	if (_offered_termination == _n_threads) {
duke@435	74	//inner_termination_loop();
duke@435	75	return true;
duke@435	76	} else {
duke@435	77	if (yield_count <= WorkStealingYieldsBeforeSleep) {
duke@435	78	yield_count++;
duke@435	79	yield();
duke@435	80	} else {
duke@435	81	if (PrintGCDetails && Verbose) {
duke@435	82	gclog_or_tty->print_cr("ParallelTaskTerminator::offer_termination() "
duke@435	83	"thread %d sleeps after %d yields",
duke@435	84	Thread::current(), yield_count);
duke@435	85	}
duke@435	86	yield_count = 0;
duke@435	87	// A sleep will cause this processor to seek work on another processor's
duke@435	88	// runqueue, if it has nothing else to run (as opposed to the yield
duke@435	89	// which may only move the thread to the end of the this processor's
duke@435	90	// runqueue).
duke@435	91	sleep(WorkStealingSleepMillis);
duke@435	92	}
duke@435	93
duke@435	94	if (peek_in_queue_set()) {
duke@435	95	Atomic::dec(&_offered_termination);
duke@435	96	return false;
duke@435	97	}
duke@435	98	}
duke@435	99	}
duke@435	100	}
duke@435	101
duke@435	102	void ParallelTaskTerminator::reset_for_reuse() {
duke@435	103	if (_offered_termination != 0) {
duke@435	104	assert(_offered_termination == _n_threads,
duke@435	105	"Terminator may still be in use");
duke@435	106	_offered_termination = 0;
duke@435	107	}
duke@435	108	}
duke@435	109
duke@435	110	bool ChunkTaskQueueWithOverflow::is_empty() {
duke@435	111	return (_chunk_queue.size() == 0) &&
duke@435	112	(_overflow_stack->length() == 0);
duke@435	113	}
duke@435	114
duke@435	115	bool ChunkTaskQueueWithOverflow::stealable_is_empty() {
duke@435	116	return _chunk_queue.size() == 0;
duke@435	117	}
duke@435	118
duke@435	119	bool ChunkTaskQueueWithOverflow::overflow_is_empty() {
duke@435	120	return _overflow_stack->length() == 0;
duke@435	121	}
duke@435	122
duke@435	123	void ChunkTaskQueueWithOverflow::initialize() {
duke@435	124	_chunk_queue.initialize();
duke@435	125	assert(_overflow_stack == 0, "Creating memory leak");
duke@435	126	_overflow_stack =
duke@435	127	new (ResourceObj::C_HEAP) GrowableArray<ChunkTask>(10, true);
duke@435	128	}
duke@435	129
duke@435	130	void ChunkTaskQueueWithOverflow::save(ChunkTask t) {
duke@435	131	if (TraceChunkTasksQueuing && Verbose) {
duke@435	132	gclog_or_tty->print_cr("CTQ: save " PTR_FORMAT, t);
duke@435	133	}
duke@435	134	if(!_chunk_queue.push(t)) {
duke@435	135	_overflow_stack->push(t);
duke@435	136	}
duke@435	137	}
duke@435	138
duke@435	139	// Note that using this method will retrieve all chunks
duke@435	140	// that have been saved but that it will always check
duke@435	141	// the overflow stack. It may be more efficient to
duke@435	142	// check the stealable queue and the overflow stack
duke@435	143	// separately.
duke@435	144	bool ChunkTaskQueueWithOverflow::retrieve(ChunkTask& chunk_task) {
duke@435	145	bool result = retrieve_from_overflow(chunk_task);
duke@435	146	if (!result) {
duke@435	147	result = retrieve_from_stealable_queue(chunk_task);
duke@435	148	}
duke@435	149	if (TraceChunkTasksQueuing && Verbose && result) {
duke@435	150	gclog_or_tty->print_cr(" CTQ: retrieve " PTR_FORMAT, result);
duke@435	151	}
duke@435	152	return result;
duke@435	153	}
duke@435	154
duke@435	155	bool ChunkTaskQueueWithOverflow::retrieve_from_stealable_queue(
duke@435	156	ChunkTask& chunk_task) {
duke@435	157	bool result = _chunk_queue.pop_local(chunk_task);
duke@435	158	if (TraceChunkTasksQueuing && Verbose) {
duke@435	159	gclog_or_tty->print_cr("CTQ: retrieve_stealable " PTR_FORMAT, chunk_task);
duke@435	160	}
duke@435	161	return result;
duke@435	162	}
duke@435	163
duke@435	164	bool ChunkTaskQueueWithOverflow::retrieve_from_overflow(
duke@435	165	ChunkTask& chunk_task) {
duke@435	166	bool result;
duke@435	167	if (!_overflow_stack->is_empty()) {
duke@435	168	chunk_task = _overflow_stack->pop();
duke@435	169	result = true;
duke@435	170	} else {
duke@435	171	chunk_task = (ChunkTask) NULL;
duke@435	172	result = false;
duke@435	173	}
duke@435	174	if (TraceChunkTasksQueuing && Verbose) {
duke@435	175	gclog_or_tty->print_cr("CTQ: retrieve_stealable " PTR_FORMAT, chunk_task);
duke@435	176	}
duke@435	177	return result;
duke@435	178	}