1 /* 2 * Copyright (c) 2002, 2017, 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::cmpxchg_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 // Set up the thread for stack overflow support 118 this->record_stack_base_and_size(); 119 this->initialize_named_thread(); 120 // Bind yourself to your processor. 121 if (processor_id() != GCTaskManager::sentinel_worker()) { 122 log_trace(gc, task, thread)("GCTaskThread::run: binding to processor %u", processor_id()); 123 if (!os::bind_to_processor(processor_id())) { 124 DEBUG_ONLY( 125 log_warning(gc)("Couldn't bind GCTaskThread %u to processor %u", 126 which(), processor_id()); 127 ) 128 } 129 } 130 // Part of thread setup. 131 // ??? Are these set up once here to make subsequent ones fast? 132 HandleMark hm_outer; 133 ResourceMark rm_outer; 134 135 TimeStamp timer; 136 137 for (;/* ever */;) { 138 // These are so we can flush the resources allocated in the inner loop. 139 HandleMark hm_inner; 140 ResourceMark rm_inner; 141 for (; /* break */; ) { 142 // This will block until there is a task to be gotten. 143 GCTask* task = manager()->get_task(which()); 144 GCIdMark gc_id_mark(task->gc_id()); 145 // Record if this is an idle task for later use. 146 bool is_idle_task = task->is_idle_task(); 147 // In case the update is costly 148 if (log_is_enabled(Debug, gc, task, time)) { 149 timer.update(); 150 } 151 152 jlong entry_time = timer.ticks(); 153 char* name = task->name(); 154 155 // If this is the barrier task, it can be destroyed 156 // by the GC task manager once the do_it() executes. 157 task->do_it(manager(), which()); 158 159 // Use the saved value of is_idle_task because references 160 // using "task" are not reliable for the barrier task. 161 if (!is_idle_task) { 162 manager()->note_completion(which()); 163 164 if (log_is_enabled(Debug, gc, task, time)) { 165 timer.update(); 166 add_task_timestamp(name, entry_time, timer.ticks()); 167 } 168 } else { 169 // idle tasks complete outside the normal accounting 170 // so that a task can complete without waiting for idle tasks. 171 // They have to be terminated separately. 172 IdleGCTask::destroy((IdleGCTask*)task); 173 set_is_working(true); 174 } 175 176 // Check if we should release our inner resources. 177 if (manager()->should_release_resources(which())) { 178 manager()->note_release(which()); 179 break; 180 } 181 } 182 } 183 }