Wed, 10 Mar 2010 21:42:26 -0800
6933402: RFE: Improve PrintSafepointStatistics output to track cleanup time
Summary: Improve the usability of safepoint statistics data. See bug evaluation for more details.
Reviewed-by: ysr, dholmes
1 /*
2 * Copyright 1997-2009 Sun Microsystems, Inc. All Rights Reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
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11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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13 * accompanied this code).
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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.
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23 */
25 # include "incls/_precompiled.incl"
26 # include "incls/_safepoint.cpp.incl"
28 // --------------------------------------------------------------------------------------------------
29 // Implementation of Safepoint begin/end
31 SafepointSynchronize::SynchronizeState volatile SafepointSynchronize::_state = SafepointSynchronize::_not_synchronized;
32 volatile int SafepointSynchronize::_waiting_to_block = 0;
33 volatile int SafepointSynchronize::_safepoint_counter = 0;
34 long SafepointSynchronize::_end_of_last_safepoint = 0;
35 static volatile int PageArmed = 0 ; // safepoint polling page is RO|RW vs PROT_NONE
36 static volatile int TryingToBlock = 0 ; // proximate value -- for advisory use only
37 static bool timeout_error_printed = false;
39 // Roll all threads forward to a safepoint and suspend them all
40 void SafepointSynchronize::begin() {
42 Thread* myThread = Thread::current();
43 assert(myThread->is_VM_thread(), "Only VM thread may execute a safepoint");
45 if (PrintSafepointStatistics || PrintSafepointStatisticsTimeout > 0) {
46 _safepoint_begin_time = os::javaTimeNanos();
47 _ts_of_current_safepoint = tty->time_stamp().seconds();
48 }
50 #ifndef SERIALGC
51 if (UseConcMarkSweepGC) {
52 // In the future we should investigate whether CMS can use the
53 // more-general mechanism below. DLD (01/05).
54 ConcurrentMarkSweepThread::synchronize(false);
55 } else if (UseG1GC) {
56 ConcurrentGCThread::safepoint_synchronize();
57 }
58 #endif // SERIALGC
60 // By getting the Threads_lock, we assure that no threads are about to start or
61 // exit. It is released again in SafepointSynchronize::end().
62 Threads_lock->lock();
64 assert( _state == _not_synchronized, "trying to safepoint synchronize with wrong state");
66 int nof_threads = Threads::number_of_threads();
68 if (TraceSafepoint) {
69 tty->print_cr("Safepoint synchronization initiated. (%d)", nof_threads);
70 }
72 RuntimeService::record_safepoint_begin();
74 {
75 MutexLocker mu(Safepoint_lock);
77 // Set number of threads to wait for, before we initiate the callbacks
78 _waiting_to_block = nof_threads;
79 TryingToBlock = 0 ;
80 int still_running = nof_threads;
82 // Save the starting time, so that it can be compared to see if this has taken
83 // too long to complete.
84 jlong safepoint_limit_time;
85 timeout_error_printed = false;
87 // PrintSafepointStatisticsTimeout can be specified separately. When
88 // specified, PrintSafepointStatistics will be set to true in
89 // deferred_initialize_stat method. The initialization has to be done
90 // early enough to avoid any races. See bug 6880029 for details.
91 if (PrintSafepointStatistics || PrintSafepointStatisticsTimeout > 0) {
92 deferred_initialize_stat();
93 }
95 // Begin the process of bringing the system to a safepoint.
96 // Java threads can be in several different states and are
97 // stopped by different mechanisms:
98 //
99 // 1. Running interpreted
100 // The interpeter dispatch table is changed to force it to
101 // check for a safepoint condition between bytecodes.
102 // 2. Running in native code
103 // When returning from the native code, a Java thread must check
104 // the safepoint _state to see if we must block. If the
105 // VM thread sees a Java thread in native, it does
106 // not wait for this thread to block. The order of the memory
107 // writes and reads of both the safepoint state and the Java
108 // threads state is critical. In order to guarantee that the
109 // memory writes are serialized with respect to each other,
110 // the VM thread issues a memory barrier instruction
111 // (on MP systems). In order to avoid the overhead of issuing
112 // a memory barrier for each Java thread making native calls, each Java
113 // thread performs a write to a single memory page after changing
114 // the thread state. The VM thread performs a sequence of
115 // mprotect OS calls which forces all previous writes from all
116 // Java threads to be serialized. This is done in the
117 // os::serialize_thread_states() call. This has proven to be
118 // much more efficient than executing a membar instruction
119 // on every call to native code.
120 // 3. Running compiled Code
121 // Compiled code reads a global (Safepoint Polling) page that
122 // is set to fault if we are trying to get to a safepoint.
123 // 4. Blocked
124 // A thread which is blocked will not be allowed to return from the
125 // block condition until the safepoint operation is complete.
126 // 5. In VM or Transitioning between states
127 // If a Java thread is currently running in the VM or transitioning
128 // between states, the safepointing code will wait for the thread to
129 // block itself when it attempts transitions to a new state.
130 //
131 _state = _synchronizing;
132 OrderAccess::fence();
134 // Flush all thread states to memory
135 if (!UseMembar) {
136 os::serialize_thread_states();
137 }
139 // Make interpreter safepoint aware
140 Interpreter::notice_safepoints();
142 if (UseCompilerSafepoints && DeferPollingPageLoopCount < 0) {
143 // Make polling safepoint aware
144 guarantee (PageArmed == 0, "invariant") ;
145 PageArmed = 1 ;
146 os::make_polling_page_unreadable();
147 }
149 // Consider using active_processor_count() ... but that call is expensive.
150 int ncpus = os::processor_count() ;
152 #ifdef ASSERT
153 for (JavaThread *cur = Threads::first(); cur != NULL; cur = cur->next()) {
154 assert(cur->safepoint_state()->is_running(), "Illegal initial state");
155 }
156 #endif // ASSERT
158 if (SafepointTimeout)
159 safepoint_limit_time = os::javaTimeNanos() + (jlong)SafepointTimeoutDelay * MICROUNITS;
161 // Iterate through all threads until it have been determined how to stop them all at a safepoint
162 unsigned int iterations = 0;
163 int steps = 0 ;
164 while(still_running > 0) {
165 for (JavaThread *cur = Threads::first(); cur != NULL; cur = cur->next()) {
166 assert(!cur->is_ConcurrentGC_thread(), "A concurrent GC thread is unexpectly being suspended");
167 ThreadSafepointState *cur_state = cur->safepoint_state();
168 if (cur_state->is_running()) {
169 cur_state->examine_state_of_thread();
170 if (!cur_state->is_running()) {
171 still_running--;
172 // consider adjusting steps downward:
173 // steps = 0
174 // steps -= NNN
175 // steps >>= 1
176 // steps = MIN(steps, 2000-100)
177 // if (iterations != 0) steps -= NNN
178 }
179 if (TraceSafepoint && Verbose) cur_state->print();
180 }
181 }
183 if (PrintSafepointStatistics && iterations == 0) {
184 begin_statistics(nof_threads, still_running);
185 }
187 if (still_running > 0) {
188 // Check for if it takes to long
189 if (SafepointTimeout && safepoint_limit_time < os::javaTimeNanos()) {
190 print_safepoint_timeout(_spinning_timeout);
191 }
193 // Spin to avoid context switching.
194 // There's a tension between allowing the mutators to run (and rendezvous)
195 // vs spinning. As the VM thread spins, wasting cycles, it consumes CPU that
196 // a mutator might otherwise use profitably to reach a safepoint. Excessive
197 // spinning by the VM thread on a saturated system can increase rendezvous latency.
198 // Blocking or yielding incur their own penalties in the form of context switching
199 // and the resultant loss of $ residency.
200 //
201 // Further complicating matters is that yield() does not work as naively expected
202 // on many platforms -- yield() does not guarantee that any other ready threads
203 // will run. As such we revert yield_all() after some number of iterations.
204 // Yield_all() is implemented as a short unconditional sleep on some platforms.
205 // Typical operating systems round a "short" sleep period up to 10 msecs, so sleeping
206 // can actually increase the time it takes the VM thread to detect that a system-wide
207 // stop-the-world safepoint has been reached. In a pathological scenario such as that
208 // described in CR6415670 the VMthread may sleep just before the mutator(s) become safe.
209 // In that case the mutators will be stalled waiting for the safepoint to complete and the
210 // the VMthread will be sleeping, waiting for the mutators to rendezvous. The VMthread
211 // will eventually wake up and detect that all mutators are safe, at which point
212 // we'll again make progress.
213 //
214 // Beware too that that the VMThread typically runs at elevated priority.
215 // Its default priority is higher than the default mutator priority.
216 // Obviously, this complicates spinning.
217 //
218 // Note too that on Windows XP SwitchThreadTo() has quite different behavior than Sleep(0).
219 // Sleep(0) will _not yield to lower priority threads, while SwitchThreadTo() will.
220 //
221 // See the comments in synchronizer.cpp for additional remarks on spinning.
222 //
223 // In the future we might:
224 // 1. Modify the safepoint scheme to avoid potentally unbounded spinning.
225 // This is tricky as the path used by a thread exiting the JVM (say on
226 // on JNI call-out) simply stores into its state field. The burden
227 // is placed on the VM thread, which must poll (spin).
228 // 2. Find something useful to do while spinning. If the safepoint is GC-related
229 // we might aggressively scan the stacks of threads that are already safe.
230 // 3. Use Solaris schedctl to examine the state of the still-running mutators.
231 // If all the mutators are ONPROC there's no reason to sleep or yield.
232 // 4. YieldTo() any still-running mutators that are ready but OFFPROC.
233 // 5. Check system saturation. If the system is not fully saturated then
234 // simply spin and avoid sleep/yield.
235 // 6. As still-running mutators rendezvous they could unpark the sleeping
236 // VMthread. This works well for still-running mutators that become
237 // safe. The VMthread must still poll for mutators that call-out.
238 // 7. Drive the policy on time-since-begin instead of iterations.
239 // 8. Consider making the spin duration a function of the # of CPUs:
240 // Spin = (((ncpus-1) * M) + K) + F(still_running)
241 // Alternately, instead of counting iterations of the outer loop
242 // we could count the # of threads visited in the inner loop, above.
243 // 9. On windows consider using the return value from SwitchThreadTo()
244 // to drive subsequent spin/SwitchThreadTo()/Sleep(N) decisions.
246 if (UseCompilerSafepoints && int(iterations) == DeferPollingPageLoopCount) {
247 guarantee (PageArmed == 0, "invariant") ;
248 PageArmed = 1 ;
249 os::make_polling_page_unreadable();
250 }
252 // Instead of (ncpus > 1) consider either (still_running < (ncpus + EPSILON)) or
253 // ((still_running + _waiting_to_block - TryingToBlock)) < ncpus)
254 ++steps ;
255 if (ncpus > 1 && steps < SafepointSpinBeforeYield) {
256 SpinPause() ; // MP-Polite spin
257 } else
258 if (steps < DeferThrSuspendLoopCount) {
259 os::NakedYield() ;
260 } else {
261 os::yield_all(steps) ;
262 // Alternately, the VM thread could transiently depress its scheduling priority or
263 // transiently increase the priority of the tardy mutator(s).
264 }
266 iterations ++ ;
267 }
268 assert(iterations < (uint)max_jint, "We have been iterating in the safepoint loop too long");
269 }
270 assert(still_running == 0, "sanity check");
272 if (PrintSafepointStatistics) {
273 update_statistics_on_spin_end();
274 }
276 // wait until all threads are stopped
277 while (_waiting_to_block > 0) {
278 if (TraceSafepoint) tty->print_cr("Waiting for %d thread(s) to block", _waiting_to_block);
279 if (!SafepointTimeout || timeout_error_printed) {
280 Safepoint_lock->wait(true); // true, means with no safepoint checks
281 } else {
282 // Compute remaining time
283 jlong remaining_time = safepoint_limit_time - os::javaTimeNanos();
285 // If there is no remaining time, then there is an error
286 if (remaining_time < 0 || Safepoint_lock->wait(true, remaining_time / MICROUNITS)) {
287 print_safepoint_timeout(_blocking_timeout);
288 }
289 }
290 }
291 assert(_waiting_to_block == 0, "sanity check");
293 #ifndef PRODUCT
294 if (SafepointTimeout) {
295 jlong current_time = os::javaTimeNanos();
296 if (safepoint_limit_time < current_time) {
297 tty->print_cr("# SafepointSynchronize: Finished after "
298 INT64_FORMAT_W(6) " ms",
299 ((current_time - safepoint_limit_time) / MICROUNITS +
300 SafepointTimeoutDelay));
301 }
302 }
303 #endif
305 assert((_safepoint_counter & 0x1) == 0, "must be even");
306 assert(Threads_lock->owned_by_self(), "must hold Threads_lock");
307 _safepoint_counter ++;
309 // Record state
310 _state = _synchronized;
312 OrderAccess::fence();
314 if (TraceSafepoint) {
315 VM_Operation *op = VMThread::vm_operation();
316 tty->print_cr("Entering safepoint region: %s", (op != NULL) ? op->name() : "no vm operation");
317 }
319 RuntimeService::record_safepoint_synchronized();
320 if (PrintSafepointStatistics) {
321 update_statistics_on_sync_end(os::javaTimeNanos());
322 }
324 // Call stuff that needs to be run when a safepoint is just about to be completed
325 do_cleanup_tasks();
327 if (PrintSafepointStatistics) {
328 // Record how much time spend on the above cleanup tasks
329 update_statistics_on_cleanup_end(os::javaTimeNanos());
330 }
331 }
332 }
334 // Wake up all threads, so they are ready to resume execution after the safepoint
335 // operation has been carried out
336 void SafepointSynchronize::end() {
338 assert(Threads_lock->owned_by_self(), "must hold Threads_lock");
339 assert((_safepoint_counter & 0x1) == 1, "must be odd");
340 _safepoint_counter ++;
341 // memory fence isn't required here since an odd _safepoint_counter
342 // value can do no harm and a fence is issued below anyway.
344 DEBUG_ONLY(Thread* myThread = Thread::current();)
345 assert(myThread->is_VM_thread(), "Only VM thread can execute a safepoint");
347 if (PrintSafepointStatistics) {
348 end_statistics(os::javaTimeNanos());
349 }
351 #ifdef ASSERT
352 // A pending_exception cannot be installed during a safepoint. The threads
353 // may install an async exception after they come back from a safepoint into
354 // pending_exception after they unblock. But that should happen later.
355 for(JavaThread *cur = Threads::first(); cur; cur = cur->next()) {
356 assert (!(cur->has_pending_exception() &&
357 cur->safepoint_state()->is_at_poll_safepoint()),
358 "safepoint installed a pending exception");
359 }
360 #endif // ASSERT
362 if (PageArmed) {
363 // Make polling safepoint aware
364 os::make_polling_page_readable();
365 PageArmed = 0 ;
366 }
368 // Remove safepoint check from interpreter
369 Interpreter::ignore_safepoints();
371 {
372 MutexLocker mu(Safepoint_lock);
374 assert(_state == _synchronized, "must be synchronized before ending safepoint synchronization");
376 // Set to not synchronized, so the threads will not go into the signal_thread_blocked method
377 // when they get restarted.
378 _state = _not_synchronized;
379 OrderAccess::fence();
381 if (TraceSafepoint) {
382 tty->print_cr("Leaving safepoint region");
383 }
385 // Start suspended threads
386 for(JavaThread *current = Threads::first(); current; current = current->next()) {
387 // A problem occurring on Solaris is when attempting to restart threads
388 // the first #cpus - 1 go well, but then the VMThread is preempted when we get
389 // to the next one (since it has been running the longest). We then have
390 // to wait for a cpu to become available before we can continue restarting
391 // threads.
392 // FIXME: This causes the performance of the VM to degrade when active and with
393 // large numbers of threads. Apparently this is due to the synchronous nature
394 // of suspending threads.
395 //
396 // TODO-FIXME: the comments above are vestigial and no longer apply.
397 // Furthermore, using solaris' schedctl in this particular context confers no benefit
398 if (VMThreadHintNoPreempt) {
399 os::hint_no_preempt();
400 }
401 ThreadSafepointState* cur_state = current->safepoint_state();
402 assert(cur_state->type() != ThreadSafepointState::_running, "Thread not suspended at safepoint");
403 cur_state->restart();
404 assert(cur_state->is_running(), "safepoint state has not been reset");
405 }
407 RuntimeService::record_safepoint_end();
409 // Release threads lock, so threads can be created/destroyed again. It will also starts all threads
410 // blocked in signal_thread_blocked
411 Threads_lock->unlock();
413 }
414 #ifndef SERIALGC
415 // If there are any concurrent GC threads resume them.
416 if (UseConcMarkSweepGC) {
417 ConcurrentMarkSweepThread::desynchronize(false);
418 } else if (UseG1GC) {
419 ConcurrentGCThread::safepoint_desynchronize();
420 }
421 #endif // SERIALGC
422 // record this time so VMThread can keep track how much time has elasped
423 // since last safepoint.
424 _end_of_last_safepoint = os::javaTimeMillis();
425 }
427 bool SafepointSynchronize::is_cleanup_needed() {
428 // Need a safepoint if some inline cache buffers is non-empty
429 if (!InlineCacheBuffer::is_empty()) return true;
430 return false;
431 }
433 jlong CounterDecay::_last_timestamp = 0;
435 static void do_method(methodOop m) {
436 m->invocation_counter()->decay();
437 }
439 void CounterDecay::decay() {
440 _last_timestamp = os::javaTimeMillis();
442 // This operation is going to be performed only at the end of a safepoint
443 // and hence GC's will not be going on, all Java mutators are suspended
444 // at this point and hence SystemDictionary_lock is also not needed.
445 assert(SafepointSynchronize::is_at_safepoint(), "can only be executed at a safepoint");
446 int nclasses = SystemDictionary::number_of_classes();
447 double classes_per_tick = nclasses * (CounterDecayMinIntervalLength * 1e-3 /
448 CounterHalfLifeTime);
449 for (int i = 0; i < classes_per_tick; i++) {
450 klassOop k = SystemDictionary::try_get_next_class();
451 if (k != NULL && k->klass_part()->oop_is_instance()) {
452 instanceKlass::cast(k)->methods_do(do_method);
453 }
454 }
455 }
457 // Various cleaning tasks that should be done periodically at safepoints
458 void SafepointSynchronize::do_cleanup_tasks() {
459 {
460 TraceTime t1("deflating idle monitors", TraceSafepoint);
461 ObjectSynchronizer::deflate_idle_monitors();
462 }
464 {
465 TraceTime t2("updating inline caches", TraceSafepoint);
466 InlineCacheBuffer::update_inline_caches();
467 }
469 if(UseCounterDecay && CounterDecay::is_decay_needed()) {
470 TraceTime t3("decaying counter", TraceSafepoint);
471 CounterDecay::decay();
472 }
474 TraceTime t4("sweeping nmethods", TraceSafepoint);
475 NMethodSweeper::sweep();
476 }
479 bool SafepointSynchronize::safepoint_safe(JavaThread *thread, JavaThreadState state) {
480 switch(state) {
481 case _thread_in_native:
482 // native threads are safe if they have no java stack or have walkable stack
483 return !thread->has_last_Java_frame() || thread->frame_anchor()->walkable();
485 // blocked threads should have already have walkable stack
486 case _thread_blocked:
487 assert(!thread->has_last_Java_frame() || thread->frame_anchor()->walkable(), "blocked and not walkable");
488 return true;
490 default:
491 return false;
492 }
493 }
496 // -------------------------------------------------------------------------------------------------------
497 // Implementation of Safepoint callback point
499 void SafepointSynchronize::block(JavaThread *thread) {
500 assert(thread != NULL, "thread must be set");
501 assert(thread->is_Java_thread(), "not a Java thread");
503 // Threads shouldn't block if they are in the middle of printing, but...
504 ttyLocker::break_tty_lock_for_safepoint(os::current_thread_id());
506 // Only bail from the block() call if the thread is gone from the
507 // thread list; starting to exit should still block.
508 if (thread->is_terminated()) {
509 // block current thread if we come here from native code when VM is gone
510 thread->block_if_vm_exited();
512 // otherwise do nothing
513 return;
514 }
516 JavaThreadState state = thread->thread_state();
517 thread->frame_anchor()->make_walkable(thread);
519 // Check that we have a valid thread_state at this point
520 switch(state) {
521 case _thread_in_vm_trans:
522 case _thread_in_Java: // From compiled code
524 // We are highly likely to block on the Safepoint_lock. In order to avoid blocking in this case,
525 // we pretend we are still in the VM.
526 thread->set_thread_state(_thread_in_vm);
528 if (is_synchronizing()) {
529 Atomic::inc (&TryingToBlock) ;
530 }
532 // We will always be holding the Safepoint_lock when we are examine the state
533 // of a thread. Hence, the instructions between the Safepoint_lock->lock() and
534 // Safepoint_lock->unlock() are happening atomic with regards to the safepoint code
535 Safepoint_lock->lock_without_safepoint_check();
536 if (is_synchronizing()) {
537 // Decrement the number of threads to wait for and signal vm thread
538 assert(_waiting_to_block > 0, "sanity check");
539 _waiting_to_block--;
540 thread->safepoint_state()->set_has_called_back(true);
542 // Consider (_waiting_to_block < 2) to pipeline the wakeup of the VM thread
543 if (_waiting_to_block == 0) {
544 Safepoint_lock->notify_all();
545 }
546 }
548 // We transition the thread to state _thread_blocked here, but
549 // we can't do our usual check for external suspension and then
550 // self-suspend after the lock_without_safepoint_check() call
551 // below because we are often called during transitions while
552 // we hold different locks. That would leave us suspended while
553 // holding a resource which results in deadlocks.
554 thread->set_thread_state(_thread_blocked);
555 Safepoint_lock->unlock();
557 // We now try to acquire the threads lock. Since this lock is hold by the VM thread during
558 // the entire safepoint, the threads will all line up here during the safepoint.
559 Threads_lock->lock_without_safepoint_check();
560 // restore original state. This is important if the thread comes from compiled code, so it
561 // will continue to execute with the _thread_in_Java state.
562 thread->set_thread_state(state);
563 Threads_lock->unlock();
564 break;
566 case _thread_in_native_trans:
567 case _thread_blocked_trans:
568 case _thread_new_trans:
569 if (thread->safepoint_state()->type() == ThreadSafepointState::_call_back) {
570 thread->print_thread_state();
571 fatal("Deadlock in safepoint code. "
572 "Should have called back to the VM before blocking.");
573 }
575 // We transition the thread to state _thread_blocked here, but
576 // we can't do our usual check for external suspension and then
577 // self-suspend after the lock_without_safepoint_check() call
578 // below because we are often called during transitions while
579 // we hold different locks. That would leave us suspended while
580 // holding a resource which results in deadlocks.
581 thread->set_thread_state(_thread_blocked);
583 // It is not safe to suspend a thread if we discover it is in _thread_in_native_trans. Hence,
584 // the safepoint code might still be waiting for it to block. We need to change the state here,
585 // so it can see that it is at a safepoint.
587 // Block until the safepoint operation is completed.
588 Threads_lock->lock_without_safepoint_check();
590 // Restore state
591 thread->set_thread_state(state);
593 Threads_lock->unlock();
594 break;
596 default:
597 fatal1("Illegal threadstate encountered: %d", state);
598 }
600 // Check for pending. async. exceptions or suspends - except if the
601 // thread was blocked inside the VM. has_special_runtime_exit_condition()
602 // is called last since it grabs a lock and we only want to do that when
603 // we must.
604 //
605 // Note: we never deliver an async exception at a polling point as the
606 // compiler may not have an exception handler for it. The polling
607 // code will notice the async and deoptimize and the exception will
608 // be delivered. (Polling at a return point is ok though). Sure is
609 // a lot of bother for a deprecated feature...
610 //
611 // We don't deliver an async exception if the thread state is
612 // _thread_in_native_trans so JNI functions won't be called with
613 // a surprising pending exception. If the thread state is going back to java,
614 // async exception is checked in check_special_condition_for_native_trans().
616 if (state != _thread_blocked_trans &&
617 state != _thread_in_vm_trans &&
618 thread->has_special_runtime_exit_condition()) {
619 thread->handle_special_runtime_exit_condition(
620 !thread->is_at_poll_safepoint() && (state != _thread_in_native_trans));
621 }
622 }
624 // ------------------------------------------------------------------------------------------------------
625 // Exception handlers
627 #ifndef PRODUCT
628 #ifdef _LP64
629 #define PTR_PAD ""
630 #else
631 #define PTR_PAD " "
632 #endif
634 static void print_ptrs(intptr_t oldptr, intptr_t newptr, bool wasoop) {
635 bool is_oop = newptr ? ((oop)newptr)->is_oop() : false;
636 tty->print_cr(PTR_FORMAT PTR_PAD " %s %c " PTR_FORMAT PTR_PAD " %s %s",
637 oldptr, wasoop?"oop":" ", oldptr == newptr ? ' ' : '!',
638 newptr, is_oop?"oop":" ", (wasoop && !is_oop) ? "STALE" : ((wasoop==false&&is_oop==false&&oldptr !=newptr)?"STOMP":" "));
639 }
641 static void print_longs(jlong oldptr, jlong newptr, bool wasoop) {
642 bool is_oop = newptr ? ((oop)(intptr_t)newptr)->is_oop() : false;
643 tty->print_cr(PTR64_FORMAT " %s %c " PTR64_FORMAT " %s %s",
644 oldptr, wasoop?"oop":" ", oldptr == newptr ? ' ' : '!',
645 newptr, is_oop?"oop":" ", (wasoop && !is_oop) ? "STALE" : ((wasoop==false&&is_oop==false&&oldptr !=newptr)?"STOMP":" "));
646 }
648 #ifdef SPARC
649 static void print_me(intptr_t *new_sp, intptr_t *old_sp, bool *was_oops) {
650 #ifdef _LP64
651 tty->print_cr("--------+------address-----+------before-----------+-------after----------+");
652 const int incr = 1; // Increment to skip a long, in units of intptr_t
653 #else
654 tty->print_cr("--------+--address-+------before-----------+-------after----------+");
655 const int incr = 2; // Increment to skip a long, in units of intptr_t
656 #endif
657 tty->print_cr("---SP---|");
658 for( int i=0; i<16; i++ ) {
659 tty->print("blob %c%d |"PTR_FORMAT" ","LO"[i>>3],i&7,new_sp); print_ptrs(*old_sp++,*new_sp++,*was_oops++); }
660 tty->print_cr("--------|");
661 for( int i1=0; i1<frame::memory_parameter_word_sp_offset-16; i1++ ) {
662 tty->print("argv pad|"PTR_FORMAT" ",new_sp); print_ptrs(*old_sp++,*new_sp++,*was_oops++); }
663 tty->print(" pad|"PTR_FORMAT" ",new_sp); print_ptrs(*old_sp++,*new_sp++,*was_oops++);
664 tty->print_cr("--------|");
665 tty->print(" G1 |"PTR_FORMAT" ",new_sp); print_longs(*(jlong*)old_sp,*(jlong*)new_sp,was_oops[incr-1]); old_sp += incr; new_sp += incr; was_oops += incr;
666 tty->print(" G3 |"PTR_FORMAT" ",new_sp); print_longs(*(jlong*)old_sp,*(jlong*)new_sp,was_oops[incr-1]); old_sp += incr; new_sp += incr; was_oops += incr;
667 tty->print(" G4 |"PTR_FORMAT" ",new_sp); print_longs(*(jlong*)old_sp,*(jlong*)new_sp,was_oops[incr-1]); old_sp += incr; new_sp += incr; was_oops += incr;
668 tty->print(" G5 |"PTR_FORMAT" ",new_sp); print_longs(*(jlong*)old_sp,*(jlong*)new_sp,was_oops[incr-1]); old_sp += incr; new_sp += incr; was_oops += incr;
669 tty->print_cr(" FSR |"PTR_FORMAT" "PTR64_FORMAT" "PTR64_FORMAT,new_sp,*(jlong*)old_sp,*(jlong*)new_sp);
670 old_sp += incr; new_sp += incr; was_oops += incr;
671 // Skip the floats
672 tty->print_cr("--Float-|"PTR_FORMAT,new_sp);
673 tty->print_cr("---FP---|");
674 old_sp += incr*32; new_sp += incr*32; was_oops += incr*32;
675 for( int i2=0; i2<16; i2++ ) {
676 tty->print("call %c%d |"PTR_FORMAT" ","LI"[i2>>3],i2&7,new_sp); print_ptrs(*old_sp++,*new_sp++,*was_oops++); }
677 tty->print_cr("");
678 }
679 #endif // SPARC
680 #endif // PRODUCT
683 void SafepointSynchronize::handle_polling_page_exception(JavaThread *thread) {
684 assert(thread->is_Java_thread(), "polling reference encountered by VM thread");
685 assert(thread->thread_state() == _thread_in_Java, "should come from Java code");
686 assert(SafepointSynchronize::is_synchronizing(), "polling encountered outside safepoint synchronization");
688 // Uncomment this to get some serious before/after printing of the
689 // Sparc safepoint-blob frame structure.
690 /*
691 intptr_t* sp = thread->last_Java_sp();
692 intptr_t stack_copy[150];
693 for( int i=0; i<150; i++ ) stack_copy[i] = sp[i];
694 bool was_oops[150];
695 for( int i=0; i<150; i++ )
696 was_oops[i] = stack_copy[i] ? ((oop)stack_copy[i])->is_oop() : false;
697 */
699 if (ShowSafepointMsgs) {
700 tty->print("handle_polling_page_exception: ");
701 }
703 if (PrintSafepointStatistics) {
704 inc_page_trap_count();
705 }
707 ThreadSafepointState* state = thread->safepoint_state();
709 state->handle_polling_page_exception();
710 // print_me(sp,stack_copy,was_oops);
711 }
714 void SafepointSynchronize::print_safepoint_timeout(SafepointTimeoutReason reason) {
715 if (!timeout_error_printed) {
716 timeout_error_printed = true;
717 // Print out the thread infor which didn't reach the safepoint for debugging
718 // purposes (useful when there are lots of threads in the debugger).
719 tty->print_cr("");
720 tty->print_cr("# SafepointSynchronize::begin: Timeout detected:");
721 if (reason == _spinning_timeout) {
722 tty->print_cr("# SafepointSynchronize::begin: Timed out while spinning to reach a safepoint.");
723 } else if (reason == _blocking_timeout) {
724 tty->print_cr("# SafepointSynchronize::begin: Timed out while waiting for threads to stop.");
725 }
727 tty->print_cr("# SafepointSynchronize::begin: Threads which did not reach the safepoint:");
728 ThreadSafepointState *cur_state;
729 ResourceMark rm;
730 for(JavaThread *cur_thread = Threads::first(); cur_thread;
731 cur_thread = cur_thread->next()) {
732 cur_state = cur_thread->safepoint_state();
734 if (cur_thread->thread_state() != _thread_blocked &&
735 ((reason == _spinning_timeout && cur_state->is_running()) ||
736 (reason == _blocking_timeout && !cur_state->has_called_back()))) {
737 tty->print("# ");
738 cur_thread->print();
739 tty->print_cr("");
740 }
741 }
742 tty->print_cr("# SafepointSynchronize::begin: (End of list)");
743 }
745 // To debug the long safepoint, specify both DieOnSafepointTimeout &
746 // ShowMessageBoxOnError.
747 if (DieOnSafepointTimeout) {
748 char msg[1024];
749 VM_Operation *op = VMThread::vm_operation();
750 sprintf(msg, "Safepoint sync time longer than " INTX_FORMAT "ms detected when executing %s.",
751 SafepointTimeoutDelay,
752 op != NULL ? op->name() : "no vm operation");
753 fatal(msg);
754 }
755 }
758 // -------------------------------------------------------------------------------------------------------
759 // Implementation of ThreadSafepointState
761 ThreadSafepointState::ThreadSafepointState(JavaThread *thread) {
762 _thread = thread;
763 _type = _running;
764 _has_called_back = false;
765 _at_poll_safepoint = false;
766 }
768 void ThreadSafepointState::create(JavaThread *thread) {
769 ThreadSafepointState *state = new ThreadSafepointState(thread);
770 thread->set_safepoint_state(state);
771 }
773 void ThreadSafepointState::destroy(JavaThread *thread) {
774 if (thread->safepoint_state()) {
775 delete(thread->safepoint_state());
776 thread->set_safepoint_state(NULL);
777 }
778 }
780 void ThreadSafepointState::examine_state_of_thread() {
781 assert(is_running(), "better be running or just have hit safepoint poll");
783 JavaThreadState state = _thread->thread_state();
785 // Check for a thread that is suspended. Note that thread resume tries
786 // to grab the Threads_lock which we own here, so a thread cannot be
787 // resumed during safepoint synchronization.
789 // We check to see if this thread is suspended without locking to
790 // avoid deadlocking with a third thread that is waiting for this
791 // thread to be suspended. The third thread can notice the safepoint
792 // that we're trying to start at the beginning of its SR_lock->wait()
793 // call. If that happens, then the third thread will block on the
794 // safepoint while still holding the underlying SR_lock. We won't be
795 // able to get the SR_lock and we'll deadlock.
796 //
797 // We don't need to grab the SR_lock here for two reasons:
798 // 1) The suspend flags are both volatile and are set with an
799 // Atomic::cmpxchg() call so we should see the suspended
800 // state right away.
801 // 2) We're being called from the safepoint polling loop; if
802 // we don't see the suspended state on this iteration, then
803 // we'll come around again.
804 //
805 bool is_suspended = _thread->is_ext_suspended();
806 if (is_suspended) {
807 roll_forward(_at_safepoint);
808 return;
809 }
811 // Some JavaThread states have an initial safepoint state of
812 // running, but are actually at a safepoint. We will happily
813 // agree and update the safepoint state here.
814 if (SafepointSynchronize::safepoint_safe(_thread, state)) {
815 roll_forward(_at_safepoint);
816 return;
817 }
819 if (state == _thread_in_vm) {
820 roll_forward(_call_back);
821 return;
822 }
824 // All other thread states will continue to run until they
825 // transition and self-block in state _blocked
826 // Safepoint polling in compiled code causes the Java threads to do the same.
827 // Note: new threads may require a malloc so they must be allowed to finish
829 assert(is_running(), "examine_state_of_thread on non-running thread");
830 return;
831 }
833 // Returns true is thread could not be rolled forward at present position.
834 void ThreadSafepointState::roll_forward(suspend_type type) {
835 _type = type;
837 switch(_type) {
838 case _at_safepoint:
839 SafepointSynchronize::signal_thread_at_safepoint();
840 break;
842 case _call_back:
843 set_has_called_back(false);
844 break;
846 case _running:
847 default:
848 ShouldNotReachHere();
849 }
850 }
852 void ThreadSafepointState::restart() {
853 switch(type()) {
854 case _at_safepoint:
855 case _call_back:
856 break;
858 case _running:
859 default:
860 tty->print_cr("restart thread "INTPTR_FORMAT" with state %d",
861 _thread, _type);
862 _thread->print();
863 ShouldNotReachHere();
864 }
865 _type = _running;
866 set_has_called_back(false);
867 }
870 void ThreadSafepointState::print_on(outputStream *st) const {
871 const char *s;
873 switch(_type) {
874 case _running : s = "_running"; break;
875 case _at_safepoint : s = "_at_safepoint"; break;
876 case _call_back : s = "_call_back"; break;
877 default:
878 ShouldNotReachHere();
879 }
881 st->print_cr("Thread: " INTPTR_FORMAT
882 " [0x%2x] State: %s _has_called_back %d _at_poll_safepoint %d",
883 _thread, _thread->osthread()->thread_id(), s, _has_called_back,
884 _at_poll_safepoint);
886 _thread->print_thread_state_on(st);
887 }
890 // ---------------------------------------------------------------------------------------------------------------------
892 // Block the thread at the safepoint poll or poll return.
893 void ThreadSafepointState::handle_polling_page_exception() {
895 // Check state. block() will set thread state to thread_in_vm which will
896 // cause the safepoint state _type to become _call_back.
897 assert(type() == ThreadSafepointState::_running,
898 "polling page exception on thread not running state");
900 // Step 1: Find the nmethod from the return address
901 if (ShowSafepointMsgs && Verbose) {
902 tty->print_cr("Polling page exception at " INTPTR_FORMAT, thread()->saved_exception_pc());
903 }
904 address real_return_addr = thread()->saved_exception_pc();
906 CodeBlob *cb = CodeCache::find_blob(real_return_addr);
907 assert(cb != NULL && cb->is_nmethod(), "return address should be in nmethod");
908 nmethod* nm = (nmethod*)cb;
910 // Find frame of caller
911 frame stub_fr = thread()->last_frame();
912 CodeBlob* stub_cb = stub_fr.cb();
913 assert(stub_cb->is_safepoint_stub(), "must be a safepoint stub");
914 RegisterMap map(thread(), true);
915 frame caller_fr = stub_fr.sender(&map);
917 // Should only be poll_return or poll
918 assert( nm->is_at_poll_or_poll_return(real_return_addr), "should not be at call" );
920 // This is a poll immediately before a return. The exception handling code
921 // has already had the effect of causing the return to occur, so the execution
922 // will continue immediately after the call. In addition, the oopmap at the
923 // return point does not mark the return value as an oop (if it is), so
924 // it needs a handle here to be updated.
925 if( nm->is_at_poll_return(real_return_addr) ) {
926 // See if return type is an oop.
927 bool return_oop = nm->method()->is_returning_oop();
928 Handle return_value;
929 if (return_oop) {
930 // The oop result has been saved on the stack together with all
931 // the other registers. In order to preserve it over GCs we need
932 // to keep it in a handle.
933 oop result = caller_fr.saved_oop_result(&map);
934 assert(result == NULL || result->is_oop(), "must be oop");
935 return_value = Handle(thread(), result);
936 assert(Universe::heap()->is_in_or_null(result), "must be heap pointer");
937 }
939 // Block the thread
940 SafepointSynchronize::block(thread());
942 // restore oop result, if any
943 if (return_oop) {
944 caller_fr.set_saved_oop_result(&map, return_value());
945 }
946 }
948 // This is a safepoint poll. Verify the return address and block.
949 else {
950 set_at_poll_safepoint(true);
952 // verify the blob built the "return address" correctly
953 assert(real_return_addr == caller_fr.pc(), "must match");
955 // Block the thread
956 SafepointSynchronize::block(thread());
957 set_at_poll_safepoint(false);
959 // If we have a pending async exception deoptimize the frame
960 // as otherwise we may never deliver it.
961 if (thread()->has_async_condition()) {
962 ThreadInVMfromJavaNoAsyncException __tiv(thread());
963 VM_DeoptimizeFrame deopt(thread(), caller_fr.id());
964 VMThread::execute(&deopt);
965 }
967 // If an exception has been installed we must check for a pending deoptimization
968 // Deoptimize frame if exception has been thrown.
970 if (thread()->has_pending_exception() ) {
971 RegisterMap map(thread(), true);
972 frame caller_fr = stub_fr.sender(&map);
973 if (caller_fr.is_deoptimized_frame()) {
974 // The exception patch will destroy registers that are still
975 // live and will be needed during deoptimization. Defer the
976 // Async exception should have defered the exception until the
977 // next safepoint which will be detected when we get into
978 // the interpreter so if we have an exception now things
979 // are messed up.
981 fatal("Exception installed and deoptimization is pending");
982 }
983 }
984 }
985 }
988 //
989 // Statistics & Instrumentations
990 //
991 SafepointSynchronize::SafepointStats* SafepointSynchronize::_safepoint_stats = NULL;
992 jlong SafepointSynchronize::_safepoint_begin_time = 0;
993 int SafepointSynchronize::_cur_stat_index = 0;
994 julong SafepointSynchronize::_safepoint_reasons[VM_Operation::VMOp_Terminating];
995 julong SafepointSynchronize::_coalesced_vmop_count = 0;
996 jlong SafepointSynchronize::_max_sync_time = 0;
997 jlong SafepointSynchronize::_max_vmop_time = 0;
998 float SafepointSynchronize::_ts_of_current_safepoint = 0.0f;
1000 static jlong cleanup_end_time = 0;
1001 static bool need_to_track_page_armed_status = false;
1002 static bool init_done = false;
1004 // Helper method to print the header.
1005 static void print_header() {
1006 tty->print(" vmop "
1007 "[threads: total initially_running wait_to_block] ");
1008 tty->print("[time: spin block sync cleanup vmop] ");
1010 // no page armed status printed out if it is always armed.
1011 if (need_to_track_page_armed_status) {
1012 tty->print("page_armed ");
1013 }
1015 tty->print_cr("page_trap_count");
1016 }
1018 void SafepointSynchronize::deferred_initialize_stat() {
1019 if (init_done) return;
1021 if (PrintSafepointStatisticsCount <= 0) {
1022 fatal("Wrong PrintSafepointStatisticsCount");
1023 }
1025 // If PrintSafepointStatisticsTimeout is specified, the statistics data will
1026 // be printed right away, in which case, _safepoint_stats will regress to
1027 // a single element array. Otherwise, it is a circular ring buffer with default
1028 // size of PrintSafepointStatisticsCount.
1029 int stats_array_size;
1030 if (PrintSafepointStatisticsTimeout > 0) {
1031 stats_array_size = 1;
1032 PrintSafepointStatistics = true;
1033 } else {
1034 stats_array_size = PrintSafepointStatisticsCount;
1035 }
1036 _safepoint_stats = (SafepointStats*)os::malloc(stats_array_size
1037 * sizeof(SafepointStats));
1038 guarantee(_safepoint_stats != NULL,
1039 "not enough memory for safepoint instrumentation data");
1041 if (UseCompilerSafepoints && DeferPollingPageLoopCount >= 0) {
1042 need_to_track_page_armed_status = true;
1043 }
1044 init_done = true;
1045 }
1047 void SafepointSynchronize::begin_statistics(int nof_threads, int nof_running) {
1048 assert(init_done, "safepoint statistics array hasn't been initialized");
1049 SafepointStats *spstat = &_safepoint_stats[_cur_stat_index];
1051 spstat->_time_stamp = _ts_of_current_safepoint;
1053 VM_Operation *op = VMThread::vm_operation();
1054 spstat->_vmop_type = (op != NULL ? op->type() : -1);
1055 if (op != NULL) {
1056 _safepoint_reasons[spstat->_vmop_type]++;
1057 }
1059 spstat->_nof_total_threads = nof_threads;
1060 spstat->_nof_initial_running_threads = nof_running;
1061 spstat->_nof_threads_hit_page_trap = 0;
1063 // Records the start time of spinning. The real time spent on spinning
1064 // will be adjusted when spin is done. Same trick is applied for time
1065 // spent on waiting for threads to block.
1066 if (nof_running != 0) {
1067 spstat->_time_to_spin = os::javaTimeNanos();
1068 } else {
1069 spstat->_time_to_spin = 0;
1070 }
1071 }
1073 void SafepointSynchronize::update_statistics_on_spin_end() {
1074 SafepointStats *spstat = &_safepoint_stats[_cur_stat_index];
1076 jlong cur_time = os::javaTimeNanos();
1078 spstat->_nof_threads_wait_to_block = _waiting_to_block;
1079 if (spstat->_nof_initial_running_threads != 0) {
1080 spstat->_time_to_spin = cur_time - spstat->_time_to_spin;
1081 }
1083 if (need_to_track_page_armed_status) {
1084 spstat->_page_armed = (PageArmed == 1);
1085 }
1087 // Records the start time of waiting for to block. Updated when block is done.
1088 if (_waiting_to_block != 0) {
1089 spstat->_time_to_wait_to_block = cur_time;
1090 } else {
1091 spstat->_time_to_wait_to_block = 0;
1092 }
1093 }
1095 void SafepointSynchronize::update_statistics_on_sync_end(jlong end_time) {
1096 SafepointStats *spstat = &_safepoint_stats[_cur_stat_index];
1098 if (spstat->_nof_threads_wait_to_block != 0) {
1099 spstat->_time_to_wait_to_block = end_time -
1100 spstat->_time_to_wait_to_block;
1101 }
1103 // Records the end time of sync which will be used to calculate the total
1104 // vm operation time. Again, the real time spending in syncing will be deducted
1105 // from the start of the sync time later when end_statistics is called.
1106 spstat->_time_to_sync = end_time - _safepoint_begin_time;
1107 if (spstat->_time_to_sync > _max_sync_time) {
1108 _max_sync_time = spstat->_time_to_sync;
1109 }
1111 spstat->_time_to_do_cleanups = end_time;
1112 }
1114 void SafepointSynchronize::update_statistics_on_cleanup_end(jlong end_time) {
1115 SafepointStats *spstat = &_safepoint_stats[_cur_stat_index];
1117 // Record how long spent in cleanup tasks.
1118 spstat->_time_to_do_cleanups = end_time - spstat->_time_to_do_cleanups;
1120 cleanup_end_time = end_time;
1121 }
1123 void SafepointSynchronize::end_statistics(jlong vmop_end_time) {
1124 SafepointStats *spstat = &_safepoint_stats[_cur_stat_index];
1126 // Update the vm operation time.
1127 spstat->_time_to_exec_vmop = vmop_end_time - cleanup_end_time;
1128 if (spstat->_time_to_exec_vmop > _max_vmop_time) {
1129 _max_vmop_time = spstat->_time_to_exec_vmop;
1130 }
1131 // Only the sync time longer than the specified
1132 // PrintSafepointStatisticsTimeout will be printed out right away.
1133 // By default, it is -1 meaning all samples will be put into the list.
1134 if ( PrintSafepointStatisticsTimeout > 0) {
1135 if (spstat->_time_to_sync > PrintSafepointStatisticsTimeout * MICROUNITS) {
1136 print_statistics();
1137 }
1138 } else {
1139 // The safepoint statistics will be printed out when the _safepoin_stats
1140 // array fills up.
1141 if (_cur_stat_index == PrintSafepointStatisticsCount - 1) {
1142 print_statistics();
1143 _cur_stat_index = 0;
1144 } else {
1145 _cur_stat_index++;
1146 }
1147 }
1148 }
1150 void SafepointSynchronize::print_statistics() {
1151 SafepointStats* sstats = _safepoint_stats;
1153 for (int index = 0; index <= _cur_stat_index; index++) {
1154 if (index % 30 == 0) {
1155 print_header();
1156 }
1157 sstats = &_safepoint_stats[index];
1158 tty->print("%.3f: ", sstats->_time_stamp);
1159 tty->print("%-26s ["
1160 INT32_FORMAT_W(8)INT32_FORMAT_W(11)INT32_FORMAT_W(15)
1161 " ] ",
1162 sstats->_vmop_type == -1 ? "no vm operation" :
1163 VM_Operation::name(sstats->_vmop_type),
1164 sstats->_nof_total_threads,
1165 sstats->_nof_initial_running_threads,
1166 sstats->_nof_threads_wait_to_block);
1167 // "/ MICROUNITS " is to convert the unit from nanos to millis.
1168 tty->print(" ["
1169 INT64_FORMAT_W(6)INT64_FORMAT_W(6)
1170 INT64_FORMAT_W(6)INT64_FORMAT_W(6)
1171 INT64_FORMAT_W(6)" ] ",
1172 sstats->_time_to_spin / MICROUNITS,
1173 sstats->_time_to_wait_to_block / MICROUNITS,
1174 sstats->_time_to_sync / MICROUNITS,
1175 sstats->_time_to_do_cleanups / MICROUNITS,
1176 sstats->_time_to_exec_vmop / MICROUNITS);
1178 if (need_to_track_page_armed_status) {
1179 tty->print(INT32_FORMAT" ", sstats->_page_armed);
1180 }
1181 tty->print_cr(INT32_FORMAT" ", sstats->_nof_threads_hit_page_trap);
1182 }
1183 }
1185 // This method will be called when VM exits. It will first call
1186 // print_statistics to print out the rest of the sampling. Then
1187 // it tries to summarize the sampling.
1188 void SafepointSynchronize::print_stat_on_exit() {
1189 if (_safepoint_stats == NULL) return;
1191 SafepointStats *spstat = &_safepoint_stats[_cur_stat_index];
1193 // During VM exit, end_statistics may not get called and in that
1194 // case, if the sync time is less than PrintSafepointStatisticsTimeout,
1195 // don't print it out.
1196 // Approximate the vm op time.
1197 _safepoint_stats[_cur_stat_index]._time_to_exec_vmop =
1198 os::javaTimeNanos() - cleanup_end_time;
1200 if ( PrintSafepointStatisticsTimeout < 0 ||
1201 spstat->_time_to_sync > PrintSafepointStatisticsTimeout * MICROUNITS) {
1202 print_statistics();
1203 }
1204 tty->print_cr("");
1206 // Print out polling page sampling status.
1207 if (!need_to_track_page_armed_status) {
1208 if (UseCompilerSafepoints) {
1209 tty->print_cr("Polling page always armed");
1210 }
1211 } else {
1212 tty->print_cr("Defer polling page loop count = %d\n",
1213 DeferPollingPageLoopCount);
1214 }
1216 for (int index = 0; index < VM_Operation::VMOp_Terminating; index++) {
1217 if (_safepoint_reasons[index] != 0) {
1218 tty->print_cr("%-26s"UINT64_FORMAT_W(10), VM_Operation::name(index),
1219 _safepoint_reasons[index]);
1220 }
1221 }
1223 tty->print_cr(UINT64_FORMAT_W(5)" VM operations coalesced during safepoint",
1224 _coalesced_vmop_count);
1225 tty->print_cr("Maximum sync time "INT64_FORMAT_W(5)" ms",
1226 _max_sync_time / MICROUNITS);
1227 tty->print_cr("Maximum vm operation time (except for Exit VM operation) "
1228 INT64_FORMAT_W(5)" ms",
1229 _max_vmop_time / MICROUNITS);
1230 }
1232 // ------------------------------------------------------------------------------------------------
1233 // Non-product code
1235 #ifndef PRODUCT
1237 void SafepointSynchronize::print_state() {
1238 if (_state == _not_synchronized) {
1239 tty->print_cr("not synchronized");
1240 } else if (_state == _synchronizing || _state == _synchronized) {
1241 tty->print_cr("State: %s", (_state == _synchronizing) ? "synchronizing" :
1242 "synchronized");
1244 for(JavaThread *cur = Threads::first(); cur; cur = cur->next()) {
1245 cur->safepoint_state()->print();
1246 }
1247 }
1248 }
1250 void SafepointSynchronize::safepoint_msg(const char* format, ...) {
1251 if (ShowSafepointMsgs) {
1252 va_list ap;
1253 va_start(ap, format);
1254 tty->vprint_cr(format, ap);
1255 va_end(ap);
1256 }
1257 }
1259 #endif // !PRODUCT