1 /*
2 * Copyright (c) 2002, 2016, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "gc/parallel/gcTaskManager.hpp"
27 #include "gc/parallel/gcTaskThread.hpp"
28 #include "gc/shared/gcId.hpp"
29 #include "logging/log.hpp"
30 #include "memory/allocation.hpp"
31 #include "memory/allocation.inline.hpp"
32 #include "memory/resourceArea.hpp"
33 #include "runtime/atomic.inline.hpp"
34 #include "runtime/handles.hpp"
35 #include "runtime/handles.inline.hpp"
36 #include "runtime/os.hpp"
37 #include "runtime/thread.hpp"
38
39 #define PARGCTHREAD "ParGC Thread"
40
41 GCTaskThread::GCTaskThread(GCTaskManager* manager,
42 uint which,
43 uint processor_id) :
44 _manager(manager),
45 _processor_id(processor_id),
46 _time_stamps(NULL),
47 _time_stamp_index(0)
48 {
49 set_id(which);
50 set_name(PARGCTHREAD "#%d", which);
51 }
52
53 GCTaskThread::~GCTaskThread() {
54 if (_time_stamps != NULL) {
55 FREE_C_HEAP_ARRAY(GCTaskTimeStamp, _time_stamps);
56 }
57 }
58
59 const char* GCTaskThread::task_name() { return PARGCTHREAD; }
60
61 GCTaskTimeStamp* GCTaskThread::time_stamp_at(uint index) {
62 guarantee(index < GCTaskTimeStampEntries, "increase GCTaskTimeStampEntries");
63 if (_time_stamps == NULL) {
64 // We allocate the _time_stamps array lazily since logging can be enabled dynamically
65 GCTaskTimeStamp* time_stamps = NEW_C_HEAP_ARRAY(GCTaskTimeStamp, GCTaskTimeStampEntries, mtGC);
66 void* old = Atomic::cmpxchg_ptr(time_stamps, &_time_stamps, NULL);
67 if (old != NULL) {
68 // Someone already setup the time stamps
69 FREE_C_HEAP_ARRAY(GCTaskTimeStamp, time_stamps);
70 }
71 }
72
73 return &(_time_stamps[index]);
74 }
75
76 void GCTaskThread::print_task_time_stamps() {
77 assert(log_is_enabled(Debug, gc, task, time), "Sanity");
78
79 // Since _time_stamps is now lazily allocated we need to check that it
80 // has in fact been allocated when calling this function.
81 if (_time_stamps != NULL) {
82 log_debug(gc, task, time)("GC-Thread %u entries: %d", id(), _time_stamp_index);
83 for(uint i=0; i<_time_stamp_index; i++) {
84 GCTaskTimeStamp* time_stamp = time_stamp_at(i);
85 log_debug(gc, task, time)("\t[ %s " JLONG_FORMAT " " JLONG_FORMAT " ]",
86 time_stamp->name(),
87 time_stamp->entry_time(),
88 time_stamp->exit_time());
89 }
90
91 // Reset after dumping the data
92 _time_stamp_index = 0;
93 }
94 }
95
96 // GC workers get tasks from the GCTaskManager and execute
97 // them in this method. If there are no tasks to execute,
98 // the GC workers wait in the GCTaskManager's get_task()
99 // for tasks to be enqueued for execution.
100
101 void GCTaskThread::run() {
102 // Set up the thread for stack overflow support
103 this->record_stack_base_and_size();
104 this->initialize_named_thread();
105 // Bind yourself to your processor.
106 if (processor_id() != GCTaskManager::sentinel_worker()) {
107 log_trace(gc, task, thread)("GCTaskThread::run: binding to processor %u", processor_id());
108 if (!os::bind_to_processor(processor_id())) {
109 DEBUG_ONLY(
110 log_warning(gc)("Couldn't bind GCTaskThread %u to processor %u",
111 which(), processor_id());
112 )
113 }
114 }
115 // Part of thread setup.
116 // ??? Are these set up once here to make subsequent ones fast?
117 HandleMark hm_outer;
118 ResourceMark rm_outer;
119
120 TimeStamp timer;
121
122 for (;/* ever */;) {
123 // These are so we can flush the resources allocated in the inner loop.
124 HandleMark hm_inner;
125 ResourceMark rm_inner;
126 for (; /* break */; ) {
127 // This will block until there is a task to be gotten.
128 GCTask* task = manager()->get_task(which());
129 GCIdMark gc_id_mark(task->gc_id());
130 // Record if this is an idle task for later use.
131 bool is_idle_task = task->is_idle_task();
132 // In case the update is costly
133 if (log_is_enabled(Debug, gc, task, time)) {
134 timer.update();
135 }
136
137 jlong entry_time = timer.ticks();
138 char* name = task->name();
139
140 // If this is the barrier task, it can be destroyed
141 // by the GC task manager once the do_it() executes.
142 task->do_it(manager(), which());
143
144 // Use the saved value of is_idle_task because references
145 // using "task" are not reliable for the barrier task.
146 if (!is_idle_task) {
147 manager()->note_completion(which());
148
149 if (log_is_enabled(Debug, gc, task, time)) {
150 timer.update();
151
152 GCTaskTimeStamp* time_stamp = time_stamp_at(_time_stamp_index);
153
154 time_stamp->set_name(name);
155 time_stamp->set_entry_time(entry_time);
156 time_stamp->set_exit_time(timer.ticks());
157
158 // Update the index after we have set up the entry correctly since
159 // GCTaskThread::print_task_time_stamps() may read this value concurrently.
160 _time_stamp_index++;
161 }
162 } else {
163 // idle tasks complete outside the normal accounting
164 // so that a task can complete without waiting for idle tasks.
165 // They have to be terminated separately.
166 IdleGCTask::destroy((IdleGCTask*)task);
167 set_is_working(true);
168 }
169
170 // Check if we should release our inner resources.
171 if (manager()->should_release_resources(which())) {
172 manager()->note_release(which());
173 break;
174 }
175 }
176 }
177 }