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 void* old = Atomic::cmpxchg_ptr(time_stamps, &_time_stamps, NULL); 81 if (old != NULL) { 82 // Someone already setup the time stamps 83 FREE_C_HEAP_ARRAY(GCTaskTimeStamp, time_stamps); 84 } 85 } 86 return &(_time_stamps[index]); 87 } 88 89 void GCTaskThread::print_task_time_stamps() { 90 assert(log_is_enabled(Debug, gc, task, time), "Sanity"); 91 92 // Since _time_stamps is now lazily allocated we need to check that it 93 // has in fact been allocated when calling this function. 94 if (_time_stamps != NULL) { 95 log_debug(gc, task, time)("GC-Thread %u entries: %d%s", id(), 96 _time_stamp_index, 97 _time_stamp_index >= GCTaskTimeStampEntries ? " (overflow)" : ""); 98 const uint max_index = MIN2(_time_stamp_index, GCTaskTimeStampEntries); 99 for (uint i = 0; i < max_index; i++) { 100 GCTaskTimeStamp* time_stamp = time_stamp_at(i); 101 log_debug(gc, task, time)("\t[ %s " JLONG_FORMAT " " JLONG_FORMAT " ]", 102 time_stamp->name(), 103 time_stamp->entry_time(), 104 time_stamp->exit_time()); 105 } 106 107 // Reset after dumping the data 108 _time_stamp_index = 0; 109 } 110 } 111 112 // GC workers get tasks from the GCTaskManager and execute 113 // them in this method. If there are no tasks to execute, 114 // the GC workers wait in the GCTaskManager's get_task() 115 // for tasks to be enqueued for execution. 116 117 void GCTaskThread::run() { 118 // Set up the thread for stack overflow support 119 this->record_stack_base_and_size(); 120 this->initialize_named_thread(); 121 // Bind yourself to your processor. 122 if (processor_id() != GCTaskManager::sentinel_worker()) { 123 log_trace(gc, task, thread)("GCTaskThread::run: binding to processor %u", processor_id()); 124 if (!os::bind_to_processor(processor_id())) { 125 DEBUG_ONLY( 126 log_warning(gc)("Couldn't bind GCTaskThread %u to processor %u", 127 which(), processor_id()); 128 ) 129 } 130 } 131 // Part of thread setup. 132 // ??? Are these set up once here to make subsequent ones fast? 133 HandleMark hm_outer; 134 ResourceMark rm_outer; 135 136 TimeStamp timer; 137 138 for (;/* ever */;) { 139 // These are so we can flush the resources allocated in the inner loop. 140 HandleMark hm_inner; 141 ResourceMark rm_inner; 142 for (; /* break */; ) { 143 // This will block until there is a task to be gotten. 144 GCTask* task = manager()->get_task(which()); 145 GCIdMark gc_id_mark(task->gc_id()); 146 // Record if this is an idle task for later use. 147 bool is_idle_task = task->is_idle_task(); 148 // In case the update is costly 149 if (log_is_enabled(Debug, gc, task, time)) { 150 timer.update(); 151 } 152 153 jlong entry_time = timer.ticks(); 154 char* name = task->name(); 155 156 // If this is the barrier task, it can be destroyed 157 // by the GC task manager once the do_it() executes. 158 task->do_it(manager(), which()); 159 160 // Use the saved value of is_idle_task because references 161 // using "task" are not reliable for the barrier task. 162 if (!is_idle_task) { 163 manager()->note_completion(which()); 164 165 if (log_is_enabled(Debug, gc, task, time)) { 166 timer.update(); 167 add_task_timestamp(name, entry_time, timer.ticks()); 168 } 169 } else { 170 // idle tasks complete outside the normal accounting 171 // so that a task can complete without waiting for idle tasks. 172 // They have to be terminated separately. 173 IdleGCTask::destroy((IdleGCTask*)task); 174 set_is_working(true); 175 } 176 177 // Check if we should release our inner resources. 178 if (manager()->should_release_resources(which())) { 179 manager()->note_release(which()); 180 break; 181 } 182 } 183 } 184 }