threadService.hpp revision 470:ad8c8ca4ab0f
1/* 2 * Copyright 2003-2008 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, 20 * CA 95054 USA or visit www.sun.com if you need additional information or 21 * have any questions. 22 * 23 */ 24 25class OopClosure; 26class ThreadDumpResult; 27class ThreadStackTrace; 28class ThreadSnapshot; 29class StackFrameInfo; 30class ThreadConcurrentLocks; 31class DeadlockCycle; 32 33// VM monitoring and management support for the thread and 34// synchronization subsystem 35// 36// Thread contention monitoring is disabled by default. 37// When enabled, the VM will begin measuring the accumulated 38// elapsed time a thread blocked on synchronization. 39// 40class ThreadService : public AllStatic { 41private: 42 // These counters could be moved to Threads class 43 static PerfCounter* _total_threads_count; 44 static PerfVariable* _live_threads_count; 45 static PerfVariable* _peak_threads_count; 46 static PerfVariable* _daemon_threads_count; 47 48 // These 2 counters are atomically incremented once the thread is exiting. 49 // They will be atomically decremented when ThreadService::remove_thread is called. 50 static volatile int _exiting_threads_count; 51 static volatile int _exiting_daemon_threads_count; 52 53 static bool _thread_monitoring_contention_enabled; 54 static bool _thread_cpu_time_enabled; 55 56 // Need to keep the list of thread dump result that 57 // keep references to methodOop since thread dump can be 58 // requested by multiple threads concurrently. 59 static ThreadDumpResult* _threaddump_list; 60 61public: 62 static void init(); 63 static void add_thread(JavaThread* thread, bool daemon); 64 static void remove_thread(JavaThread* thread, bool daemon); 65 static void current_thread_exiting(JavaThread* jt); 66 67 static bool set_thread_monitoring_contention(bool flag); 68 static bool is_thread_monitoring_contention() { return _thread_monitoring_contention_enabled; } 69 70 static bool set_thread_cpu_time_enabled(bool flag); 71 static bool is_thread_cpu_time_enabled() { return _thread_cpu_time_enabled; } 72 73 static jlong get_total_thread_count() { return _total_threads_count->get_value(); } 74 static jlong get_peak_thread_count() { return _peak_threads_count->get_value(); } 75 static jlong get_live_thread_count() { return _live_threads_count->get_value() - _exiting_threads_count; } 76 static jlong get_daemon_thread_count() { return _daemon_threads_count->get_value() - _exiting_daemon_threads_count; } 77 78 static int exiting_threads_count() { return _exiting_threads_count; } 79 static int exiting_daemon_threads_count() { return _exiting_daemon_threads_count; } 80 81 // Support for thread dump 82 static void add_thread_dump(ThreadDumpResult* dump); 83 static void remove_thread_dump(ThreadDumpResult* dump); 84 85 static Handle get_current_contended_monitor(JavaThread* thread); 86 87 // This function is called by JVM_DumpThreads. 88 static Handle dump_stack_traces(GrowableArray<instanceHandle>* threads, 89 int num_threads, TRAPS); 90 91 static void reset_peak_thread_count(); 92 static void reset_contention_count_stat(JavaThread* thread); 93 static void reset_contention_time_stat(JavaThread* thread); 94 95 static DeadlockCycle* find_deadlocks_at_safepoint(bool object_monitors_only); 96 97 // GC support 98 static void oops_do(OopClosure* f); 99}; 100 101// Per-thread Statistics for synchronization 102class ThreadStatistics : public CHeapObj { 103private: 104 // The following contention statistics are only updated by 105 // the thread owning these statistics when contention occurs. 106 107 jlong _contended_enter_count; 108 elapsedTimer _contended_enter_timer; 109 jlong _monitor_wait_count; 110 elapsedTimer _monitor_wait_timer; 111 jlong _sleep_count; 112 elapsedTimer _sleep_timer; 113 114 115 // These two reset flags are set to true when another thread 116 // requests to reset the statistics. The actual statistics 117 // are reset when the thread contention occurs and attempts 118 // to update the statistics. 119 bool _count_pending_reset; 120 bool _timer_pending_reset; 121 122 // Keep accurate times for potentially recursive class operations 123 int _class_init_recursion_count; 124 int _class_verify_recursion_count; 125 int _class_link_recursion_count; 126 127 // utility functions 128 void check_and_reset_count() { 129 if (!_count_pending_reset) return; 130 _contended_enter_count = 0; 131 _monitor_wait_count = 0; 132 _sleep_count = 0; 133 _count_pending_reset = 0; 134 } 135 void check_and_reset_timer() { 136 if (!_timer_pending_reset) return; 137 _contended_enter_timer.reset(); 138 _monitor_wait_timer.reset(); 139 _sleep_timer.reset(); 140 _timer_pending_reset = 0; 141 } 142 143public: 144 ThreadStatistics(); 145 146 jlong contended_enter_count() { return (_count_pending_reset ? 0 : _contended_enter_count); } 147 jlong contended_enter_ticks() { return (_timer_pending_reset ? 0 : _contended_enter_timer.active_ticks()); } 148 jlong monitor_wait_count() { return (_count_pending_reset ? 0 : _monitor_wait_count); } 149 jlong monitor_wait_ticks() { return (_timer_pending_reset ? 0 : _monitor_wait_timer.active_ticks()); } 150 jlong sleep_count() { return (_count_pending_reset ? 0 : _sleep_count); } 151 jlong sleep_ticks() { return (_timer_pending_reset ? 0 : _sleep_timer.active_ticks()); } 152 153 void monitor_wait() { check_and_reset_count(); _monitor_wait_count++; } 154 void monitor_wait_begin() { check_and_reset_timer(); _monitor_wait_timer.start(); } 155 void monitor_wait_end() { _monitor_wait_timer.stop(); check_and_reset_timer(); } 156 157 void thread_sleep() { check_and_reset_count(); _sleep_count++; } 158 void thread_sleep_begin() { check_and_reset_timer(); _sleep_timer.start(); } 159 void thread_sleep_end() { _sleep_timer.stop(); check_and_reset_timer(); } 160 161 void contended_enter() { check_and_reset_count(); _contended_enter_count++; } 162 void contended_enter_begin() { check_and_reset_timer(); _contended_enter_timer.start(); } 163 void contended_enter_end() { _contended_enter_timer.stop(); check_and_reset_timer(); } 164 165 void reset_count_stat() { _count_pending_reset = true; } 166 void reset_time_stat() { _timer_pending_reset = true; } 167 168 int* class_init_recursion_count_addr() { return &_class_init_recursion_count; } 169 int* class_verify_recursion_count_addr() { return &_class_verify_recursion_count; } 170 int* class_link_recursion_count_addr() { return &_class_link_recursion_count; } 171}; 172 173// Thread snapshot to represent the thread state and statistics 174class ThreadSnapshot : public CHeapObj { 175private: 176 JavaThread* _thread; 177 oop _threadObj; 178 java_lang_Thread::ThreadStatus _thread_status; 179 180 bool _is_ext_suspended; 181 bool _is_in_native; 182 183 jlong _contended_enter_ticks; 184 jlong _contended_enter_count; 185 jlong _monitor_wait_ticks; 186 jlong _monitor_wait_count; 187 jlong _sleep_ticks; 188 jlong _sleep_count; 189 oop _blocker_object; 190 oop _blocker_object_owner; 191 192 ThreadStackTrace* _stack_trace; 193 ThreadConcurrentLocks* _concurrent_locks; 194 ThreadSnapshot* _next; 195 196public: 197 // Dummy snapshot 198 ThreadSnapshot() : _thread(NULL), _threadObj(NULL), _stack_trace(NULL), _concurrent_locks(NULL), _next(NULL), 199 _blocker_object(NULL), _blocker_object_owner(NULL) {}; 200 ThreadSnapshot(JavaThread* thread); 201 ~ThreadSnapshot(); 202 203 java_lang_Thread::ThreadStatus thread_status() { return _thread_status; } 204 205 oop threadObj() const { return _threadObj; } 206 207 void set_next(ThreadSnapshot* n) { _next = n; } 208 209 bool is_ext_suspended() { return _is_ext_suspended; } 210 bool is_in_native() { return _is_in_native; } 211 212 jlong contended_enter_count() { return _contended_enter_count; } 213 jlong contended_enter_ticks() { return _contended_enter_ticks; } 214 jlong monitor_wait_count() { return _monitor_wait_count; } 215 jlong monitor_wait_ticks() { return _monitor_wait_ticks; } 216 jlong sleep_count() { return _sleep_count; } 217 jlong sleep_ticks() { return _sleep_ticks; } 218 219 220 oop blocker_object() { return _blocker_object; } 221 oop blocker_object_owner() { return _blocker_object_owner; } 222 223 ThreadSnapshot* next() const { return _next; } 224 ThreadStackTrace* get_stack_trace() { return _stack_trace; } 225 ThreadConcurrentLocks* get_concurrent_locks() { return _concurrent_locks; } 226 227 void dump_stack_at_safepoint(int max_depth, bool with_locked_monitors); 228 void set_concurrent_locks(ThreadConcurrentLocks* l) { _concurrent_locks = l; } 229 void oops_do(OopClosure* f); 230}; 231 232class ThreadStackTrace : public CHeapObj { 233 private: 234 JavaThread* _thread; 235 int _depth; // number of stack frames added 236 bool _with_locked_monitors; 237 GrowableArray<StackFrameInfo*>* _frames; 238 GrowableArray<oop>* _jni_locked_monitors; 239 240 public: 241 242 ThreadStackTrace(JavaThread* thread, bool with_locked_monitors); 243 ~ThreadStackTrace(); 244 245 JavaThread* thread() { return _thread; } 246 StackFrameInfo* stack_frame_at(int i) { return _frames->at(i); } 247 int get_stack_depth() { return _depth; } 248 249 void add_stack_frame(javaVFrame* jvf); 250 void dump_stack_at_safepoint(int max_depth); 251 Handle allocate_fill_stack_trace_element_array(TRAPS); 252 void oops_do(OopClosure* f); 253 GrowableArray<oop>* jni_locked_monitors() { return _jni_locked_monitors; } 254 int num_jni_locked_monitors() { return (_jni_locked_monitors != NULL ? _jni_locked_monitors->length() : 0); } 255 256 bool is_owned_monitor_on_stack(oop object); 257 void add_jni_locked_monitor(oop object) { _jni_locked_monitors->append(object); } 258}; 259 260// StackFrameInfo for keeping methodOop and bci during 261// stack walking for later construction of StackTraceElement[] 262// Java instances 263class StackFrameInfo : public CHeapObj { 264 private: 265 methodOop _method; 266 int _bci; 267 GrowableArray<oop>* _locked_monitors; // list of object monitors locked by this frame 268 269 public: 270 271 StackFrameInfo(javaVFrame* jvf, bool with_locked_monitors); 272 ~StackFrameInfo() { 273 if (_locked_monitors != NULL) { 274 delete _locked_monitors; 275 } 276 }; 277 methodOop method() const { return _method; } 278 int bci() const { return _bci; } 279 void oops_do(OopClosure* f); 280 281 int num_locked_monitors() { return (_locked_monitors != NULL ? _locked_monitors->length() : 0); } 282 GrowableArray<oop>* locked_monitors() { return _locked_monitors; } 283 284 void print_on(outputStream* st) const; 285}; 286 287class ThreadConcurrentLocks : public CHeapObj { 288private: 289 GrowableArray<instanceOop>* _owned_locks; 290 ThreadConcurrentLocks* _next; 291 JavaThread* _thread; 292 public: 293 ThreadConcurrentLocks(JavaThread* thread); 294 ~ThreadConcurrentLocks(); 295 296 void add_lock(instanceOop o); 297 void set_next(ThreadConcurrentLocks* n) { _next = n; } 298 ThreadConcurrentLocks* next() { return _next; } 299 JavaThread* java_thread() { return _thread; } 300 GrowableArray<instanceOop>* owned_locks() { return _owned_locks; } 301 void oops_do(OopClosure* f); 302}; 303 304class ConcurrentLocksDump : public StackObj { 305 private: 306 ThreadConcurrentLocks* _map; 307 ThreadConcurrentLocks* _last; // Last ThreadConcurrentLocks in the map 308 bool _retain_map_on_free; 309 310 void build_map(GrowableArray<oop>* aos_objects); 311 void add_lock(JavaThread* thread, instanceOop o); 312 313 public: 314 ConcurrentLocksDump(bool retain_map_on_free) : _map(NULL), _last(NULL), _retain_map_on_free(retain_map_on_free) {}; 315 ConcurrentLocksDump() : _map(NULL), _last(NULL), _retain_map_on_free(false) {}; 316 ~ConcurrentLocksDump(); 317 318 void dump_at_safepoint(); 319 ThreadConcurrentLocks* thread_concurrent_locks(JavaThread* thread); 320 void print_locks_on(JavaThread* t, outputStream* st); 321}; 322 323class ThreadDumpResult : public StackObj { 324 private: 325 int _num_threads; 326 int _num_snapshots; 327 ThreadSnapshot* _snapshots; 328 ThreadSnapshot* _last; 329 ThreadDumpResult* _next; 330 public: 331 ThreadDumpResult(); 332 ThreadDumpResult(int num_threads); 333 ~ThreadDumpResult(); 334 335 void add_thread_snapshot(ThreadSnapshot* ts); 336 void set_next(ThreadDumpResult* next) { _next = next; } 337 ThreadDumpResult* next() { return _next; } 338 int num_threads() { return _num_threads; } 339 int num_snapshots() { return _num_snapshots; } 340 ThreadSnapshot* snapshots() { return _snapshots; } 341 void oops_do(OopClosure* f); 342}; 343 344class DeadlockCycle : public CHeapObj { 345 private: 346 bool _is_deadlock; 347 GrowableArray<JavaThread*>* _threads; 348 DeadlockCycle* _next; 349 public: 350 DeadlockCycle(); 351 ~DeadlockCycle(); 352 353 DeadlockCycle* next() { return _next; } 354 void set_next(DeadlockCycle* d) { _next = d; } 355 void add_thread(JavaThread* t) { _threads->append(t); } 356 void reset() { _is_deadlock = false; _threads->clear(); } 357 void set_deadlock(bool value) { _is_deadlock = value; } 358 bool is_deadlock() { return _is_deadlock; } 359 int num_threads() { return _threads->length(); } 360 GrowableArray<JavaThread*>* threads() { return _threads; } 361 void print_on(outputStream* st) const; 362}; 363 364// Utility class to get list of java threads. 365class ThreadsListEnumerator : public StackObj { 366private: 367 GrowableArray<instanceHandle>* _threads_array; 368public: 369 ThreadsListEnumerator(Thread* cur_thread, 370 bool include_jvmti_agent_threads = false, 371 bool include_jni_attaching_threads = true); 372 int num_threads() { return _threads_array->length(); } 373 instanceHandle get_threadObj(int index) { return _threads_array->at(index); } 374}; 375 376 377// abstract utility class to set new thread states, and restore previous after the block exits 378class JavaThreadStatusChanger : public StackObj { 379 private: 380 java_lang_Thread::ThreadStatus _old_state; 381 JavaThread* _java_thread; 382 bool _is_alive; 383 384 void save_old_state(JavaThread* java_thread) { 385 _java_thread = java_thread; 386 _is_alive = is_alive(java_thread); 387 if (is_alive()) { 388 _old_state = java_lang_Thread::get_thread_status(_java_thread->threadObj()); 389 } 390 } 391 392 public: 393 static void set_thread_status(JavaThread* java_thread, 394 java_lang_Thread::ThreadStatus state) { 395 java_lang_Thread::set_thread_status(java_thread->threadObj(), state); 396 } 397 398 void set_thread_status(java_lang_Thread::ThreadStatus state) { 399 if (is_alive()) { 400 set_thread_status(_java_thread, state); 401 } 402 } 403 404 JavaThreadStatusChanger(JavaThread* java_thread, 405 java_lang_Thread::ThreadStatus state) { 406 save_old_state(java_thread); 407 set_thread_status(state); 408 } 409 410 JavaThreadStatusChanger(JavaThread* java_thread) { 411 save_old_state(java_thread); 412 } 413 414 ~JavaThreadStatusChanger() { 415 set_thread_status(_old_state); 416 } 417 418 static bool is_alive(JavaThread* java_thread) { 419 return java_thread != NULL && java_thread->threadObj() != NULL; 420 } 421 422 bool is_alive() { 423 return _is_alive; 424 } 425}; 426 427// Change status to waiting on an object (timed or indefinite) 428class JavaThreadInObjectWaitState : public JavaThreadStatusChanger { 429 private: 430 ThreadStatistics* _stat; 431 bool _active; 432 433 public: 434 JavaThreadInObjectWaitState(JavaThread *java_thread, bool timed) : 435 JavaThreadStatusChanger(java_thread, 436 timed ? java_lang_Thread::IN_OBJECT_WAIT_TIMED : java_lang_Thread::IN_OBJECT_WAIT) { 437 if (is_alive()) { 438 _stat = java_thread->get_thread_stat(); 439 _active = ThreadService::is_thread_monitoring_contention(); 440 _stat->monitor_wait(); 441 if (_active) { 442 _stat->monitor_wait_begin(); 443 } 444 } else { 445 _active = false; 446 } 447 } 448 449 ~JavaThreadInObjectWaitState() { 450 if (_active) { 451 _stat->monitor_wait_end(); 452 } 453 } 454}; 455 456// Change status to parked (timed or indefinite) 457class JavaThreadParkedState : public JavaThreadStatusChanger { 458 private: 459 ThreadStatistics* _stat; 460 bool _active; 461 462 public: 463 JavaThreadParkedState(JavaThread *java_thread, bool timed) : 464 JavaThreadStatusChanger(java_thread, 465 timed ? java_lang_Thread::PARKED_TIMED : java_lang_Thread::PARKED) { 466 if (is_alive()) { 467 _stat = java_thread->get_thread_stat(); 468 _active = ThreadService::is_thread_monitoring_contention(); 469 _stat->monitor_wait(); 470 if (_active) { 471 _stat->monitor_wait_begin(); 472 } 473 } else { 474 _active = false; 475 } 476 } 477 478 ~JavaThreadParkedState() { 479 if (_active) { 480 _stat->monitor_wait_end(); 481 } 482 } 483}; 484 485// Change status to blocked on (re-)entering a synchronization block 486class JavaThreadBlockedOnMonitorEnterState : public JavaThreadStatusChanger { 487 private: 488 ThreadStatistics* _stat; 489 bool _active; 490 491 static bool contended_enter_begin(JavaThread *java_thread) { 492 set_thread_status(java_thread, java_lang_Thread::BLOCKED_ON_MONITOR_ENTER); 493 ThreadStatistics* stat = java_thread->get_thread_stat(); 494 stat->contended_enter(); 495 bool active = ThreadService::is_thread_monitoring_contention(); 496 if (active) { 497 stat->contended_enter_begin(); 498 } 499 return active; 500 } 501 502 public: 503 // java_thread is waiting thread being blocked on monitor reenter. 504 // Current thread is the notifying thread which holds the monitor. 505 static bool wait_reenter_begin(JavaThread *java_thread, ObjectMonitor *obj_m) { 506 assert((java_thread != NULL), "Java thread should not be null here"); 507 bool active = false; 508 if (is_alive(java_thread) && ServiceUtil::visible_oop((oop)obj_m->object())) { 509 active = contended_enter_begin(java_thread); 510 } 511 return active; 512 } 513 514 static void wait_reenter_end(JavaThread *java_thread, bool active) { 515 if (active) { 516 java_thread->get_thread_stat()->contended_enter_end(); 517 } 518 set_thread_status(java_thread, java_lang_Thread::RUNNABLE); 519 } 520 521 JavaThreadBlockedOnMonitorEnterState(JavaThread *java_thread, ObjectMonitor *obj_m) : 522 JavaThreadStatusChanger(java_thread) { 523 assert((java_thread != NULL), "Java thread should not be null here"); 524 // Change thread status and collect contended enter stats for monitor contended 525 // enter done for external java world objects and it is contended. All other cases 526 // like for vm internal objects and for external objects which are not contended 527 // thread status is not changed and contended enter stat is not collected. 528 _active = false; 529 if (is_alive() && ServiceUtil::visible_oop((oop)obj_m->object()) && obj_m->contentions() > 0) { 530 _stat = java_thread->get_thread_stat(); 531 _active = contended_enter_begin(java_thread); 532 } 533 } 534 535 ~JavaThreadBlockedOnMonitorEnterState() { 536 if (_active) { 537 _stat->contended_enter_end(); 538 } 539 } 540}; 541 542// Change status to sleeping 543class JavaThreadSleepState : public JavaThreadStatusChanger { 544 private: 545 ThreadStatistics* _stat; 546 bool _active; 547 public: 548 JavaThreadSleepState(JavaThread *java_thread) : 549 JavaThreadStatusChanger(java_thread, java_lang_Thread::SLEEPING) { 550 if (is_alive()) { 551 _stat = java_thread->get_thread_stat(); 552 _active = ThreadService::is_thread_monitoring_contention(); 553 _stat->thread_sleep(); 554 if (_active) { 555 _stat->thread_sleep_begin(); 556 } 557 } else { 558 _active = false; 559 } 560 } 561 562 ~JavaThreadSleepState() { 563 if (_active) { 564 _stat->thread_sleep_end(); 565 } 566 } 567}; 568