1 /*
2 * Copyright (c) 2002, 2019, 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 void GCTaskThread::add_task_timestamp(const char* name, jlong t_entry, jlong t_exit) {
58 if (_time_stamp_index < GCTaskTimeStampEntries) {
59 GCTaskTimeStamp* time_stamp = time_stamp_at(_time_stamp_index);
60 time_stamp->set_name(name);
61 time_stamp->set_entry_time(t_entry);
62 time_stamp->set_exit_time(t_exit);
63 } else {
64 if (_time_stamp_index == GCTaskTimeStampEntries) {
65 log_warning(gc, task, time)("GC-thread %u: Too many timestamps, ignoring future ones. "
66 "Increase GCTaskTimeStampEntries to get more info.",
67 id());
68 }
69 // Let _time_stamp_index keep counting to give the user an idea about how many
70 // are needed.
71 }
72 _time_stamp_index++;
73 }
74
75 GCTaskTimeStamp* GCTaskThread::time_stamp_at(uint index) {
76 assert(index < GCTaskTimeStampEntries, "Precondition");
77 if (_time_stamps == NULL) {
78 // We allocate the _time_stamps array lazily since logging can be enabled dynamically
79 GCTaskTimeStamp* time_stamps = NEW_C_HEAP_ARRAY(GCTaskTimeStamp, GCTaskTimeStampEntries, mtGC);
80 if (!Atomic::replace_if_null(time_stamps, &_time_stamps)) {
81 // Someone already setup the time stamps
82 FREE_C_HEAP_ARRAY(GCTaskTimeStamp, time_stamps);
83 }
84 }
85 return &(_time_stamps[index]);
86 }
87
88 void GCTaskThread::print_task_time_stamps() {
89 assert(log_is_enabled(Debug, gc, task, time), "Sanity");
90
91 // Since _time_stamps is now lazily allocated we need to check that it
92 // has in fact been allocated when calling this function.
93 if (_time_stamps != NULL) {
94 log_debug(gc, task, time)("GC-Thread %u entries: %d%s", id(),
95 _time_stamp_index,
96 _time_stamp_index >= GCTaskTimeStampEntries ? " (overflow)" : "");
97 const uint max_index = MIN2(_time_stamp_index, GCTaskTimeStampEntries);
98 for (uint i = 0; i < max_index; i++) {
99 GCTaskTimeStamp* time_stamp = time_stamp_at(i);
100 log_debug(gc, task, time)("\t[ %s " JLONG_FORMAT " " JLONG_FORMAT " ]",
101 time_stamp->name(),
102 time_stamp->entry_time(),
103 time_stamp->exit_time());
104 }
105
106 // Reset after dumping the data
107 _time_stamp_index = 0;
108 }
109 }
110
111 // GC workers get tasks from the GCTaskManager and execute
112 // them in this method. If there are no tasks to execute,
113 // the GC workers wait in the GCTaskManager's get_task()
114 // for tasks to be enqueued for execution.
115
116 void GCTaskThread::run() {
117 // Bind yourself to your processor.
118 if (processor_id() != GCTaskManager::sentinel_worker()) {
119 log_trace(gc, task, thread)("GCTaskThread::run: binding to processor %u", processor_id());
120 if (!os::bind_to_processor(processor_id())) {
121 DEBUG_ONLY(
122 log_warning(gc)("Couldn't bind GCTaskThread %u to processor %u",
123 which(), processor_id());
124 )
125 }
126 }
127 // Part of thread setup.
128 // ??? Are these set up once here to make subsequent ones fast?
129 HandleMark hm_outer;
130 ResourceMark rm_outer;
131
132 TimeStamp timer;
133
134 for (;/* ever */;) {
135 // These are so we can flush the resources allocated in the inner loop.
136 HandleMark hm_inner;
137 ResourceMark rm_inner;
138 for (; /* break */; ) {
139 // This will block until there is a task to be gotten.
140 GCTask* task = manager()->get_task(which());
141 GCIdMark gc_id_mark(task->gc_id());
142 // Record if this is an idle task for later use.
143 bool is_idle_task = task->is_idle_task();
144 // In case the update is costly
145 if (log_is_enabled(Debug, gc, task, time)) {
146 timer.update();
147 }
148
149 jlong entry_time = timer.ticks();
150 char* name = task->name();
151
152 // If this is the barrier task, it can be destroyed
153 // by the GC task manager once the do_it() executes.
154 task->do_it(manager(), which());
155
156 // Use the saved value of is_idle_task because references
157 // using "task" are not reliable for the barrier task.
158 if (!is_idle_task) {
159 manager()->note_completion(which());
160
161 if (log_is_enabled(Debug, gc, task, time)) {
162 timer.update();
163 add_task_timestamp(name, entry_time, timer.ticks());
164 }
165 } else {
166 // idle tasks complete outside the normal accounting
167 // so that a task can complete without waiting for idle tasks.
168 // They have to be terminated separately.
169 IdleGCTask::destroy((IdleGCTask*)task);
170 }
171
172 // Check if we should release our inner resources.
173 if (manager()->should_release_resources(which())) {
174 manager()->note_release(which());
175 break;
176 }
177 }
178 }
179 }