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.hpp"
34 #include "runtime/handles.hpp"
35 #include "runtime/handles.inline.hpp"
36 #include "runtime/os.hpp"
37 #include "runtime/thread.hpp"
38
39 GCTaskThread::GCTaskThread(GCTaskManager* manager,
40 uint which,
41 uint processor_id) :
42 _manager(manager),
43 _processor_id(processor_id),
44 _time_stamps(NULL),
45 _time_stamp_index(0)
46 {
47 set_id(which);
48 set_name("%s#%d", manager->group_name(), which);
49 }
50
51 GCTaskThread::~GCTaskThread() {
52 if (_time_stamps != NULL) {
53 FREE_C_HEAP_ARRAY(GCTaskTimeStamp, _time_stamps);
54 }
55 }
56
57 GCTaskTimeStamp* GCTaskThread::time_stamp_at(uint index) {
58 guarantee(index < GCTaskTimeStampEntries, "increase GCTaskTimeStampEntries");
59 GCTaskTimeStamp* time_stamps = (GCTaskTimeStamp*)OrderAccess::load_ptr_acquire(&_time_stamps);
60 if (time_stamps == NULL) {
61 // We allocate the _time_stamps array lazily since logging can be enabled dynamically
62 time_stamps = NEW_C_HEAP_ARRAY(GCTaskTimeStamp, GCTaskTimeStampEntries, mtGC);
63 void* old = Atomic::cmpxchg_ptr(time_stamps, &_time_stamps, NULL);
64 if (old != NULL) {
65 // Someone already setup the time stamps
66 FREE_C_HEAP_ARRAY(GCTaskTimeStamp, time_stamps);
67 }
68 }
69
70 return &(time_stamps[index]);
71 }
72
73 void GCTaskThread::print_task_time_stamps() {
74 assert(log_is_enabled(Debug, gc, task, time), "Sanity");
75
76 // Since _time_stamps is now lazily allocated we need to check that it
77 // has in fact been allocated when calling this function.
78 GCTaskTimeStamp* time_stamps = (GCTaskTimeStamp*)OrderAccess::load_ptr_acquire(&_time_stamps);
79 if (time_stamps != NULL) {
80 log_debug(gc, task, time)("GC-Thread %u entries: %d", id(), _time_stamp_index);
81 for(uint i=0; i<_time_stamp_index; i++) {
82 GCTaskTimeStamp* time_stamp = time_stamp_at(i);
83 log_debug(gc, task, time)("\t[ %s " JLONG_FORMAT " " JLONG_FORMAT " ]",
84 time_stamp->name(),
85 time_stamp->entry_time(),
86 time_stamp->exit_time());
87 }
88
89 // Reset after dumping the data
90 _time_stamp_index = 0;
91 }
92 }
93
94 // GC workers get tasks from the GCTaskManager and execute
95 // them in this method. If there are no tasks to execute,
96 // the GC workers wait in the GCTaskManager's get_task()
97 // for tasks to be enqueued for execution.
98
99 void GCTaskThread::run() {
100 // Set up the thread for stack overflow support
101 this->record_stack_base_and_size();
102 this->initialize_named_thread();
103 // Bind yourself to your processor.
104 if (processor_id() != GCTaskManager::sentinel_worker()) {
105 log_trace(gc, task, thread)("GCTaskThread::run: binding to processor %u", processor_id());
106 if (!os::bind_to_processor(processor_id())) {
107 DEBUG_ONLY(
108 log_warning(gc)("Couldn't bind GCTaskThread %u to processor %u",
109 which(), processor_id());
110 )
111 }
112 }
113 // Part of thread setup.
114 // ??? Are these set up once here to make subsequent ones fast?
115 HandleMark hm_outer;
116 ResourceMark rm_outer;
117
118 TimeStamp timer;
119
120 for (;/* ever */;) {
121 // These are so we can flush the resources allocated in the inner loop.
122 HandleMark hm_inner;
123 ResourceMark rm_inner;
124 for (; /* break */; ) {
125 // This will block until there is a task to be gotten.
126 GCTask* task = manager()->get_task(which());
127 GCIdMark gc_id_mark(task->gc_id());
128 // Record if this is an idle task for later use.
129 bool is_idle_task = task->is_idle_task();
130 // In case the update is costly
131 if (log_is_enabled(Debug, gc, task, time)) {
132 timer.update();
133 }
134
135 jlong entry_time = timer.ticks();
136 char* name = task->name();
137
138 // If this is the barrier task, it can be destroyed
139 // by the GC task manager once the do_it() executes.
140 task->do_it(manager(), which());
141
142 // Use the saved value of is_idle_task because references
143 // using "task" are not reliable for the barrier task.
144 if (!is_idle_task) {
145 manager()->note_completion(which());
146
147 if (log_is_enabled(Debug, gc, task, time)) {
148 timer.update();
149
150 GCTaskTimeStamp* time_stamp = time_stamp_at(_time_stamp_index);
151
152 time_stamp->set_name(name);
153 time_stamp->set_entry_time(entry_time);
154 time_stamp->set_exit_time(timer.ticks());
155
156 // Update the index after we have set up the entry correctly since
157 // GCTaskThread::print_task_time_stamps() may read this value concurrently.
158 _time_stamp_index++;
159 }
160 } else {
161 // idle tasks complete outside the normal accounting
162 // so that a task can complete without waiting for idle tasks.
163 // They have to be terminated separately.
164 IdleGCTask::destroy((IdleGCTask*)task);
165 set_is_working(true);
166 }
167
168 // Check if we should release our inner resources.
169 if (manager()->should_release_resources(which())) {
170 manager()->note_release(which());
171 break;
172 }
173 }
174 }
175 }