threadService.hpp revision 1988:b1a2afa37ec4
1/* 2 * Copyright (c) 2003, 2011, 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#ifndef SHARE_VM_SERVICES_THREADSERVICE_HPP 26#define SHARE_VM_SERVICES_THREADSERVICE_HPP 27 28#include "classfile/javaClasses.hpp" 29#include "runtime/handles.hpp" 30#include "runtime/init.hpp" 31#include "runtime/jniHandles.hpp" 32#include "runtime/objectMonitor.hpp" 33#include "runtime/objectMonitor.inline.hpp" 34#include "runtime/perfData.hpp" 35#include "services/management.hpp" 36#include "services/serviceUtil.hpp" 37 38class OopClosure; 39class ThreadDumpResult; 40class ThreadStackTrace; 41class ThreadSnapshot; 42class StackFrameInfo; 43class ThreadConcurrentLocks; 44class DeadlockCycle; 45 46// VM monitoring and management support for the thread and 47// synchronization subsystem 48// 49// Thread contention monitoring is disabled by default. 50// When enabled, the VM will begin measuring the accumulated 51// elapsed time a thread blocked on synchronization. 52// 53class ThreadService : public AllStatic { 54private: 55 // These counters could be moved to Threads class 56 static PerfCounter* _total_threads_count; 57 static PerfVariable* _live_threads_count; 58 static PerfVariable* _peak_threads_count; 59 static PerfVariable* _daemon_threads_count; 60 61 // These 2 counters are atomically incremented once the thread is exiting. 62 // They will be atomically decremented when ThreadService::remove_thread is called. 63 static volatile int _exiting_threads_count; 64 static volatile int _exiting_daemon_threads_count; 65 66 static bool _thread_monitoring_contention_enabled; 67 static bool _thread_cpu_time_enabled; 68 static bool _thread_allocated_memory_enabled; 69 70 // Need to keep the list of thread dump result that 71 // keep references to methodOop since thread dump can be 72 // requested by multiple threads concurrently. 73 static ThreadDumpResult* _threaddump_list; 74 75public: 76 static void init(); 77 static void add_thread(JavaThread* thread, bool daemon); 78 static void remove_thread(JavaThread* thread, bool daemon); 79 static void current_thread_exiting(JavaThread* jt); 80 81 static bool set_thread_monitoring_contention(bool flag); 82 static bool is_thread_monitoring_contention() { return _thread_monitoring_contention_enabled; } 83 84 static bool set_thread_cpu_time_enabled(bool flag); 85 static bool is_thread_cpu_time_enabled() { return _thread_cpu_time_enabled; } 86 87 static bool set_thread_allocated_memory_enabled(bool flag); 88 static bool is_thread_allocated_memory_enabled() { return _thread_cpu_time_enabled; } 89 90 static jlong get_total_thread_count() { return _total_threads_count->get_value(); } 91 static jlong get_peak_thread_count() { return _peak_threads_count->get_value(); } 92 static jlong get_live_thread_count() { return _live_threads_count->get_value() - _exiting_threads_count; } 93 static jlong get_daemon_thread_count() { return _daemon_threads_count->get_value() - _exiting_daemon_threads_count; } 94 95 static int exiting_threads_count() { return _exiting_threads_count; } 96 static int exiting_daemon_threads_count() { return _exiting_daemon_threads_count; } 97 98 // Support for thread dump 99 static void add_thread_dump(ThreadDumpResult* dump); 100 static void remove_thread_dump(ThreadDumpResult* dump); 101 102 static Handle get_current_contended_monitor(JavaThread* thread); 103 104 // This function is called by JVM_DumpThreads. 105 static Handle dump_stack_traces(GrowableArray<instanceHandle>* threads, 106 int num_threads, TRAPS); 107 108 static void reset_peak_thread_count(); 109 static void reset_contention_count_stat(JavaThread* thread); 110 static void reset_contention_time_stat(JavaThread* thread); 111 112 static DeadlockCycle* find_deadlocks_at_safepoint(bool object_monitors_only); 113 114 // GC support 115 static void oops_do(OopClosure* f); 116}; 117 118// Per-thread Statistics for synchronization 119class ThreadStatistics : public CHeapObj { 120private: 121 // The following contention statistics are only updated by 122 // the thread owning these statistics when contention occurs. 123 124 jlong _contended_enter_count; 125 elapsedTimer _contended_enter_timer; 126 jlong _monitor_wait_count; 127 elapsedTimer _monitor_wait_timer; 128 jlong _sleep_count; 129 elapsedTimer _sleep_timer; 130 131 132 // These two reset flags are set to true when another thread 133 // requests to reset the statistics. The actual statistics 134 // are reset when the thread contention occurs and attempts 135 // to update the statistics. 136 bool _count_pending_reset; 137 bool _timer_pending_reset; 138 139 // Keep accurate times for potentially recursive class operations 140 int _perf_recursion_counts[6]; 141 elapsedTimer _perf_timers[6]; 142 143 // utility functions 144 void check_and_reset_count() { 145 if (!_count_pending_reset) return; 146 _contended_enter_count = 0; 147 _monitor_wait_count = 0; 148 _sleep_count = 0; 149 _count_pending_reset = 0; 150 } 151 void check_and_reset_timer() { 152 if (!_timer_pending_reset) return; 153 _contended_enter_timer.reset(); 154 _monitor_wait_timer.reset(); 155 _sleep_timer.reset(); 156 _timer_pending_reset = 0; 157 } 158 159public: 160 ThreadStatistics(); 161 162 jlong contended_enter_count() { return (_count_pending_reset ? 0 : _contended_enter_count); } 163 jlong contended_enter_ticks() { return (_timer_pending_reset ? 0 : _contended_enter_timer.active_ticks()); } 164 jlong monitor_wait_count() { return (_count_pending_reset ? 0 : _monitor_wait_count); } 165 jlong monitor_wait_ticks() { return (_timer_pending_reset ? 0 : _monitor_wait_timer.active_ticks()); } 166 jlong sleep_count() { return (_count_pending_reset ? 0 : _sleep_count); } 167 jlong sleep_ticks() { return (_timer_pending_reset ? 0 : _sleep_timer.active_ticks()); } 168 169 void monitor_wait() { check_and_reset_count(); _monitor_wait_count++; } 170 void monitor_wait_begin() { check_and_reset_timer(); _monitor_wait_timer.start(); } 171 void monitor_wait_end() { _monitor_wait_timer.stop(); check_and_reset_timer(); } 172 173 void thread_sleep() { check_and_reset_count(); _sleep_count++; } 174 void thread_sleep_begin() { check_and_reset_timer(); _sleep_timer.start(); } 175 void thread_sleep_end() { _sleep_timer.stop(); check_and_reset_timer(); } 176 177 void contended_enter() { check_and_reset_count(); _contended_enter_count++; } 178 void contended_enter_begin() { check_and_reset_timer(); _contended_enter_timer.start(); } 179 void contended_enter_end() { _contended_enter_timer.stop(); check_and_reset_timer(); } 180 181 void reset_count_stat() { _count_pending_reset = true; } 182 void reset_time_stat() { _timer_pending_reset = true; } 183 184 int* perf_recursion_counts_addr() { return _perf_recursion_counts; } 185 elapsedTimer* perf_timers_addr() { return _perf_timers; } 186}; 187 188// Thread snapshot to represent the thread state and statistics 189class ThreadSnapshot : public CHeapObj { 190private: 191 JavaThread* _thread; 192 oop _threadObj; 193 java_lang_Thread::ThreadStatus _thread_status; 194 195 bool _is_ext_suspended; 196 bool _is_in_native; 197 198 jlong _contended_enter_ticks; 199 jlong _contended_enter_count; 200 jlong _monitor_wait_ticks; 201 jlong _monitor_wait_count; 202 jlong _sleep_ticks; 203 jlong _sleep_count; 204 oop _blocker_object; 205 oop _blocker_object_owner; 206 207 ThreadStackTrace* _stack_trace; 208 ThreadConcurrentLocks* _concurrent_locks; 209 ThreadSnapshot* _next; 210 211public: 212 // Dummy snapshot 213 ThreadSnapshot() : _thread(NULL), _threadObj(NULL), _stack_trace(NULL), _concurrent_locks(NULL), _next(NULL), 214 _blocker_object(NULL), _blocker_object_owner(NULL) {}; 215 ThreadSnapshot(JavaThread* thread); 216 ~ThreadSnapshot(); 217 218 java_lang_Thread::ThreadStatus thread_status() { return _thread_status; } 219 220 oop threadObj() const { return _threadObj; } 221 222 void set_next(ThreadSnapshot* n) { _next = n; } 223 224 bool is_ext_suspended() { return _is_ext_suspended; } 225 bool is_in_native() { return _is_in_native; } 226 227 jlong contended_enter_count() { return _contended_enter_count; } 228 jlong contended_enter_ticks() { return _contended_enter_ticks; } 229 jlong monitor_wait_count() { return _monitor_wait_count; } 230 jlong monitor_wait_ticks() { return _monitor_wait_ticks; } 231 jlong sleep_count() { return _sleep_count; } 232 jlong sleep_ticks() { return _sleep_ticks; } 233 234 235 oop blocker_object() { return _blocker_object; } 236 oop blocker_object_owner() { return _blocker_object_owner; } 237 238 ThreadSnapshot* next() const { return _next; } 239 ThreadStackTrace* get_stack_trace() { return _stack_trace; } 240 ThreadConcurrentLocks* get_concurrent_locks() { return _concurrent_locks; } 241 242 void dump_stack_at_safepoint(int max_depth, bool with_locked_monitors); 243 void set_concurrent_locks(ThreadConcurrentLocks* l) { _concurrent_locks = l; } 244 void oops_do(OopClosure* f); 245}; 246 247class ThreadStackTrace : public CHeapObj { 248 private: 249 JavaThread* _thread; 250 int _depth; // number of stack frames added 251 bool _with_locked_monitors; 252 GrowableArray<StackFrameInfo*>* _frames; 253 GrowableArray<oop>* _jni_locked_monitors; 254 255 public: 256 257 ThreadStackTrace(JavaThread* thread, bool with_locked_monitors); 258 ~ThreadStackTrace(); 259 260 JavaThread* thread() { return _thread; } 261 StackFrameInfo* stack_frame_at(int i) { return _frames->at(i); } 262 int get_stack_depth() { return _depth; } 263 264 void add_stack_frame(javaVFrame* jvf); 265 void dump_stack_at_safepoint(int max_depth); 266 Handle allocate_fill_stack_trace_element_array(TRAPS); 267 void oops_do(OopClosure* f); 268 GrowableArray<oop>* jni_locked_monitors() { return _jni_locked_monitors; } 269 int num_jni_locked_monitors() { return (_jni_locked_monitors != NULL ? _jni_locked_monitors->length() : 0); } 270 271 bool is_owned_monitor_on_stack(oop object); 272 void add_jni_locked_monitor(oop object) { _jni_locked_monitors->append(object); } 273}; 274 275// StackFrameInfo for keeping methodOop and bci during 276// stack walking for later construction of StackTraceElement[] 277// Java instances 278class StackFrameInfo : public CHeapObj { 279 private: 280 methodOop _method; 281 int _bci; 282 GrowableArray<oop>* _locked_monitors; // list of object monitors locked by this frame 283 284 public: 285 286 StackFrameInfo(javaVFrame* jvf, bool with_locked_monitors); 287 ~StackFrameInfo() { 288 if (_locked_monitors != NULL) { 289 delete _locked_monitors; 290 } 291 }; 292 methodOop method() const { return _method; } 293 int bci() const { return _bci; } 294 void oops_do(OopClosure* f); 295 296 int num_locked_monitors() { return (_locked_monitors != NULL ? _locked_monitors->length() : 0); } 297 GrowableArray<oop>* locked_monitors() { return _locked_monitors; } 298 299 void print_on(outputStream* st) const; 300}; 301 302class ThreadConcurrentLocks : public CHeapObj { 303private: 304 GrowableArray<instanceOop>* _owned_locks; 305 ThreadConcurrentLocks* _next; 306 JavaThread* _thread; 307 public: 308 ThreadConcurrentLocks(JavaThread* thread); 309 ~ThreadConcurrentLocks(); 310 311 void add_lock(instanceOop o); 312 void set_next(ThreadConcurrentLocks* n) { _next = n; } 313 ThreadConcurrentLocks* next() { return _next; } 314 JavaThread* java_thread() { return _thread; } 315 GrowableArray<instanceOop>* owned_locks() { return _owned_locks; } 316 void oops_do(OopClosure* f); 317}; 318 319class ConcurrentLocksDump : public StackObj { 320 private: 321 ThreadConcurrentLocks* _map; 322 ThreadConcurrentLocks* _last; // Last ThreadConcurrentLocks in the map 323 bool _retain_map_on_free; 324 325 void build_map(GrowableArray<oop>* aos_objects); 326 void add_lock(JavaThread* thread, instanceOop o); 327 328 public: 329 ConcurrentLocksDump(bool retain_map_on_free) : _map(NULL), _last(NULL), _retain_map_on_free(retain_map_on_free) {}; 330 ConcurrentLocksDump() : _map(NULL), _last(NULL), _retain_map_on_free(false) {}; 331 ~ConcurrentLocksDump(); 332 333 void dump_at_safepoint(); 334 ThreadConcurrentLocks* thread_concurrent_locks(JavaThread* thread); 335 void print_locks_on(JavaThread* t, outputStream* st); 336}; 337 338class ThreadDumpResult : public StackObj { 339 private: 340 int _num_threads; 341 int _num_snapshots; 342 ThreadSnapshot* _snapshots; 343 ThreadSnapshot* _last; 344 ThreadDumpResult* _next; 345 public: 346 ThreadDumpResult(); 347 ThreadDumpResult(int num_threads); 348 ~ThreadDumpResult(); 349 350 void add_thread_snapshot(ThreadSnapshot* ts); 351 void set_next(ThreadDumpResult* next) { _next = next; } 352 ThreadDumpResult* next() { return _next; } 353 int num_threads() { return _num_threads; } 354 int num_snapshots() { return _num_snapshots; } 355 ThreadSnapshot* snapshots() { return _snapshots; } 356 void oops_do(OopClosure* f); 357}; 358 359class DeadlockCycle : public CHeapObj { 360 private: 361 bool _is_deadlock; 362 GrowableArray<JavaThread*>* _threads; 363 DeadlockCycle* _next; 364 public: 365 DeadlockCycle(); 366 ~DeadlockCycle(); 367 368 DeadlockCycle* next() { return _next; } 369 void set_next(DeadlockCycle* d) { _next = d; } 370 void add_thread(JavaThread* t) { _threads->append(t); } 371 void reset() { _is_deadlock = false; _threads->clear(); } 372 void set_deadlock(bool value) { _is_deadlock = value; } 373 bool is_deadlock() { return _is_deadlock; } 374 int num_threads() { return _threads->length(); } 375 GrowableArray<JavaThread*>* threads() { return _threads; } 376 void print_on(outputStream* st) const; 377}; 378 379// Utility class to get list of java threads. 380class ThreadsListEnumerator : public StackObj { 381private: 382 GrowableArray<instanceHandle>* _threads_array; 383public: 384 ThreadsListEnumerator(Thread* cur_thread, 385 bool include_jvmti_agent_threads = false, 386 bool include_jni_attaching_threads = true); 387 int num_threads() { return _threads_array->length(); } 388 instanceHandle get_threadObj(int index) { return _threads_array->at(index); } 389}; 390 391 392// abstract utility class to set new thread states, and restore previous after the block exits 393class JavaThreadStatusChanger : public StackObj { 394 private: 395 java_lang_Thread::ThreadStatus _old_state; 396 JavaThread* _java_thread; 397 bool _is_alive; 398 399 void save_old_state(JavaThread* java_thread) { 400 _java_thread = java_thread; 401 _is_alive = is_alive(java_thread); 402 if (is_alive()) { 403 _old_state = java_lang_Thread::get_thread_status(_java_thread->threadObj()); 404 } 405 } 406 407 public: 408 static void set_thread_status(JavaThread* java_thread, 409 java_lang_Thread::ThreadStatus state) { 410 java_lang_Thread::set_thread_status(java_thread->threadObj(), state); 411 } 412 413 void set_thread_status(java_lang_Thread::ThreadStatus state) { 414 if (is_alive()) { 415 set_thread_status(_java_thread, state); 416 } 417 } 418 419 JavaThreadStatusChanger(JavaThread* java_thread, 420 java_lang_Thread::ThreadStatus state) { 421 save_old_state(java_thread); 422 set_thread_status(state); 423 } 424 425 JavaThreadStatusChanger(JavaThread* java_thread) { 426 save_old_state(java_thread); 427 } 428 429 ~JavaThreadStatusChanger() { 430 set_thread_status(_old_state); 431 } 432 433 static bool is_alive(JavaThread* java_thread) { 434 return java_thread != NULL && java_thread->threadObj() != NULL; 435 } 436 437 bool is_alive() { 438 return _is_alive; 439 } 440}; 441 442// Change status to waiting on an object (timed or indefinite) 443class JavaThreadInObjectWaitState : public JavaThreadStatusChanger { 444 private: 445 ThreadStatistics* _stat; 446 bool _active; 447 448 public: 449 JavaThreadInObjectWaitState(JavaThread *java_thread, bool timed) : 450 JavaThreadStatusChanger(java_thread, 451 timed ? java_lang_Thread::IN_OBJECT_WAIT_TIMED : java_lang_Thread::IN_OBJECT_WAIT) { 452 if (is_alive()) { 453 _stat = java_thread->get_thread_stat(); 454 _active = ThreadService::is_thread_monitoring_contention(); 455 _stat->monitor_wait(); 456 if (_active) { 457 _stat->monitor_wait_begin(); 458 } 459 } else { 460 _active = false; 461 } 462 } 463 464 ~JavaThreadInObjectWaitState() { 465 if (_active) { 466 _stat->monitor_wait_end(); 467 } 468 } 469}; 470 471// Change status to parked (timed or indefinite) 472class JavaThreadParkedState : public JavaThreadStatusChanger { 473 private: 474 ThreadStatistics* _stat; 475 bool _active; 476 477 public: 478 JavaThreadParkedState(JavaThread *java_thread, bool timed) : 479 JavaThreadStatusChanger(java_thread, 480 timed ? java_lang_Thread::PARKED_TIMED : java_lang_Thread::PARKED) { 481 if (is_alive()) { 482 _stat = java_thread->get_thread_stat(); 483 _active = ThreadService::is_thread_monitoring_contention(); 484 _stat->monitor_wait(); 485 if (_active) { 486 _stat->monitor_wait_begin(); 487 } 488 } else { 489 _active = false; 490 } 491 } 492 493 ~JavaThreadParkedState() { 494 if (_active) { 495 _stat->monitor_wait_end(); 496 } 497 } 498}; 499 500// Change status to blocked on (re-)entering a synchronization block 501class JavaThreadBlockedOnMonitorEnterState : public JavaThreadStatusChanger { 502 private: 503 ThreadStatistics* _stat; 504 bool _active; 505 506 static bool contended_enter_begin(JavaThread *java_thread) { 507 set_thread_status(java_thread, java_lang_Thread::BLOCKED_ON_MONITOR_ENTER); 508 ThreadStatistics* stat = java_thread->get_thread_stat(); 509 stat->contended_enter(); 510 bool active = ThreadService::is_thread_monitoring_contention(); 511 if (active) { 512 stat->contended_enter_begin(); 513 } 514 return active; 515 } 516 517 public: 518 // java_thread is waiting thread being blocked on monitor reenter. 519 // Current thread is the notifying thread which holds the monitor. 520 static bool wait_reenter_begin(JavaThread *java_thread, ObjectMonitor *obj_m) { 521 assert((java_thread != NULL), "Java thread should not be null here"); 522 bool active = false; 523 if (is_alive(java_thread) && ServiceUtil::visible_oop((oop)obj_m->object())) { 524 active = contended_enter_begin(java_thread); 525 } 526 return active; 527 } 528 529 static void wait_reenter_end(JavaThread *java_thread, bool active) { 530 if (active) { 531 java_thread->get_thread_stat()->contended_enter_end(); 532 } 533 set_thread_status(java_thread, java_lang_Thread::RUNNABLE); 534 } 535 536 JavaThreadBlockedOnMonitorEnterState(JavaThread *java_thread, ObjectMonitor *obj_m) : 537 JavaThreadStatusChanger(java_thread) { 538 assert((java_thread != NULL), "Java thread should not be null here"); 539 // Change thread status and collect contended enter stats for monitor contended 540 // enter done for external java world objects and it is contended. All other cases 541 // like for vm internal objects and for external objects which are not contended 542 // thread status is not changed and contended enter stat is not collected. 543 _active = false; 544 if (is_alive() && ServiceUtil::visible_oop((oop)obj_m->object()) && obj_m->contentions() > 0) { 545 _stat = java_thread->get_thread_stat(); 546 _active = contended_enter_begin(java_thread); 547 } 548 } 549 550 ~JavaThreadBlockedOnMonitorEnterState() { 551 if (_active) { 552 _stat->contended_enter_end(); 553 } 554 } 555}; 556 557// Change status to sleeping 558class JavaThreadSleepState : public JavaThreadStatusChanger { 559 private: 560 ThreadStatistics* _stat; 561 bool _active; 562 public: 563 JavaThreadSleepState(JavaThread *java_thread) : 564 JavaThreadStatusChanger(java_thread, java_lang_Thread::SLEEPING) { 565 if (is_alive()) { 566 _stat = java_thread->get_thread_stat(); 567 _active = ThreadService::is_thread_monitoring_contention(); 568 _stat->thread_sleep(); 569 if (_active) { 570 _stat->thread_sleep_begin(); 571 } 572 } else { 573 _active = false; 574 } 575 } 576 577 ~JavaThreadSleepState() { 578 if (_active) { 579 _stat->thread_sleep_end(); 580 } 581 } 582}; 583 584#endif // SHARE_VM_SERVICES_THREADSERVICE_HPP 585