Mon, 04 Jan 2010 14:51:26 -0800
6637203: Classunloading messages go to stdout rather than Xloggc file, causing hangs when stdout is closed
Summary: Decoupled TraceClassUnloading from verbose:gc, JVMTI_VERBOSE_GC and PrintGC[Details], making it settable in a manner identical to TraceClassLoading. Reverted an inadvertent change of TraceClassUnloading output in a previous changeset from gclog back to tty.
Reviewed-by: coleenp, dholmes, jmasa, poonam
duke@435 | 1 | /* |
xdono@1014 | 2 | * Copyright 1997-2009 Sun Microsystems, Inc. All Rights Reserved. |
duke@435 | 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
duke@435 | 4 | * |
duke@435 | 5 | * This code is free software; you can redistribute it and/or modify it |
duke@435 | 6 | * under the terms of the GNU General Public License version 2 only, as |
duke@435 | 7 | * published by the Free Software Foundation. |
duke@435 | 8 | * |
duke@435 | 9 | * This code is distributed in the hope that it will be useful, but WITHOUT |
duke@435 | 10 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
duke@435 | 11 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
duke@435 | 12 | * version 2 for more details (a copy is included in the LICENSE file that |
duke@435 | 13 | * accompanied this code). |
duke@435 | 14 | * |
duke@435 | 15 | * You should have received a copy of the GNU General Public License version |
duke@435 | 16 | * 2 along with this work; if not, write to the Free Software Foundation, |
duke@435 | 17 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
duke@435 | 18 | * |
duke@435 | 19 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
duke@435 | 20 | * CA 95054 USA or visit www.sun.com if you need additional information or |
duke@435 | 21 | * have any questions. |
duke@435 | 22 | * |
duke@435 | 23 | */ |
duke@435 | 24 | |
duke@435 | 25 | # include "incls/_precompiled.incl" |
duke@435 | 26 | # include "incls/_safepoint.cpp.incl" |
duke@435 | 27 | |
duke@435 | 28 | // -------------------------------------------------------------------------------------------------- |
duke@435 | 29 | // Implementation of Safepoint begin/end |
duke@435 | 30 | |
duke@435 | 31 | SafepointSynchronize::SynchronizeState volatile SafepointSynchronize::_state = SafepointSynchronize::_not_synchronized; |
duke@435 | 32 | volatile int SafepointSynchronize::_waiting_to_block = 0; |
duke@435 | 33 | jlong SafepointSynchronize::_last_safepoint = 0; |
duke@435 | 34 | volatile int SafepointSynchronize::_safepoint_counter = 0; |
duke@435 | 35 | static volatile int PageArmed = 0 ; // safepoint polling page is RO|RW vs PROT_NONE |
duke@435 | 36 | static volatile int TryingToBlock = 0 ; // proximate value -- for advisory use only |
duke@435 | 37 | static bool timeout_error_printed = false; |
duke@435 | 38 | |
duke@435 | 39 | // Roll all threads forward to a safepoint and suspend them all |
duke@435 | 40 | void SafepointSynchronize::begin() { |
duke@435 | 41 | |
duke@435 | 42 | Thread* myThread = Thread::current(); |
duke@435 | 43 | assert(myThread->is_VM_thread(), "Only VM thread may execute a safepoint"); |
duke@435 | 44 | |
duke@435 | 45 | _last_safepoint = os::javaTimeNanos(); |
duke@435 | 46 | |
duke@435 | 47 | #ifndef SERIALGC |
duke@435 | 48 | if (UseConcMarkSweepGC) { |
duke@435 | 49 | // In the future we should investigate whether CMS can use the |
duke@435 | 50 | // more-general mechanism below. DLD (01/05). |
duke@435 | 51 | ConcurrentMarkSweepThread::synchronize(false); |
ysr@1280 | 52 | } else if (UseG1GC) { |
duke@435 | 53 | ConcurrentGCThread::safepoint_synchronize(); |
duke@435 | 54 | } |
duke@435 | 55 | #endif // SERIALGC |
duke@435 | 56 | |
duke@435 | 57 | // By getting the Threads_lock, we assure that no threads are about to start or |
duke@435 | 58 | // exit. It is released again in SafepointSynchronize::end(). |
duke@435 | 59 | Threads_lock->lock(); |
duke@435 | 60 | |
duke@435 | 61 | assert( _state == _not_synchronized, "trying to safepoint synchronize with wrong state"); |
duke@435 | 62 | |
duke@435 | 63 | int nof_threads = Threads::number_of_threads(); |
duke@435 | 64 | |
duke@435 | 65 | if (TraceSafepoint) { |
duke@435 | 66 | tty->print_cr("Safepoint synchronization initiated. (%d)", nof_threads); |
duke@435 | 67 | } |
duke@435 | 68 | |
duke@435 | 69 | RuntimeService::record_safepoint_begin(); |
duke@435 | 70 | |
duke@435 | 71 | { |
duke@435 | 72 | MutexLocker mu(Safepoint_lock); |
duke@435 | 73 | |
duke@435 | 74 | // Set number of threads to wait for, before we initiate the callbacks |
duke@435 | 75 | _waiting_to_block = nof_threads; |
duke@435 | 76 | TryingToBlock = 0 ; |
duke@435 | 77 | int still_running = nof_threads; |
duke@435 | 78 | |
duke@435 | 79 | // Save the starting time, so that it can be compared to see if this has taken |
duke@435 | 80 | // too long to complete. |
duke@435 | 81 | jlong safepoint_limit_time; |
duke@435 | 82 | timeout_error_printed = false; |
duke@435 | 83 | |
xlu@1438 | 84 | // PrintSafepointStatisticsTimeout can be specified separately. When |
xlu@1438 | 85 | // specified, PrintSafepointStatistics will be set to true in |
xlu@1438 | 86 | // deferred_initialize_stat method. The initialization has to be done |
xlu@1438 | 87 | // early enough to avoid any races. See bug 6880029 for details. |
xlu@1438 | 88 | if (PrintSafepointStatistics || PrintSafepointStatisticsTimeout > 0) { |
xlu@1438 | 89 | deferred_initialize_stat(); |
xlu@1438 | 90 | } |
xlu@1438 | 91 | |
duke@435 | 92 | // Begin the process of bringing the system to a safepoint. |
duke@435 | 93 | // Java threads can be in several different states and are |
duke@435 | 94 | // stopped by different mechanisms: |
duke@435 | 95 | // |
duke@435 | 96 | // 1. Running interpreted |
duke@435 | 97 | // The interpeter dispatch table is changed to force it to |
duke@435 | 98 | // check for a safepoint condition between bytecodes. |
duke@435 | 99 | // 2. Running in native code |
duke@435 | 100 | // When returning from the native code, a Java thread must check |
duke@435 | 101 | // the safepoint _state to see if we must block. If the |
duke@435 | 102 | // VM thread sees a Java thread in native, it does |
duke@435 | 103 | // not wait for this thread to block. The order of the memory |
duke@435 | 104 | // writes and reads of both the safepoint state and the Java |
duke@435 | 105 | // threads state is critical. In order to guarantee that the |
duke@435 | 106 | // memory writes are serialized with respect to each other, |
duke@435 | 107 | // the VM thread issues a memory barrier instruction |
duke@435 | 108 | // (on MP systems). In order to avoid the overhead of issuing |
duke@435 | 109 | // a memory barrier for each Java thread making native calls, each Java |
duke@435 | 110 | // thread performs a write to a single memory page after changing |
duke@435 | 111 | // the thread state. The VM thread performs a sequence of |
duke@435 | 112 | // mprotect OS calls which forces all previous writes from all |
duke@435 | 113 | // Java threads to be serialized. This is done in the |
duke@435 | 114 | // os::serialize_thread_states() call. This has proven to be |
duke@435 | 115 | // much more efficient than executing a membar instruction |
duke@435 | 116 | // on every call to native code. |
duke@435 | 117 | // 3. Running compiled Code |
duke@435 | 118 | // Compiled code reads a global (Safepoint Polling) page that |
duke@435 | 119 | // is set to fault if we are trying to get to a safepoint. |
duke@435 | 120 | // 4. Blocked |
duke@435 | 121 | // A thread which is blocked will not be allowed to return from the |
duke@435 | 122 | // block condition until the safepoint operation is complete. |
duke@435 | 123 | // 5. In VM or Transitioning between states |
duke@435 | 124 | // If a Java thread is currently running in the VM or transitioning |
duke@435 | 125 | // between states, the safepointing code will wait for the thread to |
duke@435 | 126 | // block itself when it attempts transitions to a new state. |
duke@435 | 127 | // |
duke@435 | 128 | _state = _synchronizing; |
duke@435 | 129 | OrderAccess::fence(); |
duke@435 | 130 | |
duke@435 | 131 | // Flush all thread states to memory |
duke@435 | 132 | if (!UseMembar) { |
duke@435 | 133 | os::serialize_thread_states(); |
duke@435 | 134 | } |
duke@435 | 135 | |
duke@435 | 136 | // Make interpreter safepoint aware |
duke@435 | 137 | Interpreter::notice_safepoints(); |
duke@435 | 138 | |
duke@435 | 139 | if (UseCompilerSafepoints && DeferPollingPageLoopCount < 0) { |
duke@435 | 140 | // Make polling safepoint aware |
duke@435 | 141 | guarantee (PageArmed == 0, "invariant") ; |
duke@435 | 142 | PageArmed = 1 ; |
duke@435 | 143 | os::make_polling_page_unreadable(); |
duke@435 | 144 | } |
duke@435 | 145 | |
duke@435 | 146 | // Consider using active_processor_count() ... but that call is expensive. |
duke@435 | 147 | int ncpus = os::processor_count() ; |
duke@435 | 148 | |
duke@435 | 149 | #ifdef ASSERT |
duke@435 | 150 | for (JavaThread *cur = Threads::first(); cur != NULL; cur = cur->next()) { |
duke@435 | 151 | assert(cur->safepoint_state()->is_running(), "Illegal initial state"); |
duke@435 | 152 | } |
duke@435 | 153 | #endif // ASSERT |
duke@435 | 154 | |
duke@435 | 155 | if (SafepointTimeout) |
duke@435 | 156 | safepoint_limit_time = os::javaTimeNanos() + (jlong)SafepointTimeoutDelay * MICROUNITS; |
duke@435 | 157 | |
duke@435 | 158 | // Iterate through all threads until it have been determined how to stop them all at a safepoint |
duke@435 | 159 | unsigned int iterations = 0; |
duke@435 | 160 | int steps = 0 ; |
duke@435 | 161 | while(still_running > 0) { |
duke@435 | 162 | for (JavaThread *cur = Threads::first(); cur != NULL; cur = cur->next()) { |
duke@435 | 163 | assert(!cur->is_ConcurrentGC_thread(), "A concurrent GC thread is unexpectly being suspended"); |
duke@435 | 164 | ThreadSafepointState *cur_state = cur->safepoint_state(); |
duke@435 | 165 | if (cur_state->is_running()) { |
duke@435 | 166 | cur_state->examine_state_of_thread(); |
duke@435 | 167 | if (!cur_state->is_running()) { |
duke@435 | 168 | still_running--; |
duke@435 | 169 | // consider adjusting steps downward: |
duke@435 | 170 | // steps = 0 |
duke@435 | 171 | // steps -= NNN |
duke@435 | 172 | // steps >>= 1 |
duke@435 | 173 | // steps = MIN(steps, 2000-100) |
duke@435 | 174 | // if (iterations != 0) steps -= NNN |
duke@435 | 175 | } |
duke@435 | 176 | if (TraceSafepoint && Verbose) cur_state->print(); |
duke@435 | 177 | } |
duke@435 | 178 | } |
duke@435 | 179 | |
xlu@1438 | 180 | if (PrintSafepointStatistics && iterations == 0) { |
duke@435 | 181 | begin_statistics(nof_threads, still_running); |
duke@435 | 182 | } |
duke@435 | 183 | |
duke@435 | 184 | if (still_running > 0) { |
duke@435 | 185 | // Check for if it takes to long |
duke@435 | 186 | if (SafepointTimeout && safepoint_limit_time < os::javaTimeNanos()) { |
duke@435 | 187 | print_safepoint_timeout(_spinning_timeout); |
duke@435 | 188 | } |
duke@435 | 189 | |
duke@435 | 190 | // Spin to avoid context switching. |
duke@435 | 191 | // There's a tension between allowing the mutators to run (and rendezvous) |
duke@435 | 192 | // vs spinning. As the VM thread spins, wasting cycles, it consumes CPU that |
duke@435 | 193 | // a mutator might otherwise use profitably to reach a safepoint. Excessive |
duke@435 | 194 | // spinning by the VM thread on a saturated system can increase rendezvous latency. |
duke@435 | 195 | // Blocking or yielding incur their own penalties in the form of context switching |
duke@435 | 196 | // and the resultant loss of $ residency. |
duke@435 | 197 | // |
duke@435 | 198 | // Further complicating matters is that yield() does not work as naively expected |
duke@435 | 199 | // on many platforms -- yield() does not guarantee that any other ready threads |
duke@435 | 200 | // will run. As such we revert yield_all() after some number of iterations. |
duke@435 | 201 | // Yield_all() is implemented as a short unconditional sleep on some platforms. |
duke@435 | 202 | // Typical operating systems round a "short" sleep period up to 10 msecs, so sleeping |
duke@435 | 203 | // can actually increase the time it takes the VM thread to detect that a system-wide |
duke@435 | 204 | // stop-the-world safepoint has been reached. In a pathological scenario such as that |
duke@435 | 205 | // described in CR6415670 the VMthread may sleep just before the mutator(s) become safe. |
duke@435 | 206 | // In that case the mutators will be stalled waiting for the safepoint to complete and the |
duke@435 | 207 | // the VMthread will be sleeping, waiting for the mutators to rendezvous. The VMthread |
duke@435 | 208 | // will eventually wake up and detect that all mutators are safe, at which point |
duke@435 | 209 | // we'll again make progress. |
duke@435 | 210 | // |
duke@435 | 211 | // Beware too that that the VMThread typically runs at elevated priority. |
duke@435 | 212 | // Its default priority is higher than the default mutator priority. |
duke@435 | 213 | // Obviously, this complicates spinning. |
duke@435 | 214 | // |
duke@435 | 215 | // Note too that on Windows XP SwitchThreadTo() has quite different behavior than Sleep(0). |
duke@435 | 216 | // Sleep(0) will _not yield to lower priority threads, while SwitchThreadTo() will. |
duke@435 | 217 | // |
duke@435 | 218 | // See the comments in synchronizer.cpp for additional remarks on spinning. |
duke@435 | 219 | // |
duke@435 | 220 | // In the future we might: |
duke@435 | 221 | // 1. Modify the safepoint scheme to avoid potentally unbounded spinning. |
duke@435 | 222 | // This is tricky as the path used by a thread exiting the JVM (say on |
duke@435 | 223 | // on JNI call-out) simply stores into its state field. The burden |
duke@435 | 224 | // is placed on the VM thread, which must poll (spin). |
duke@435 | 225 | // 2. Find something useful to do while spinning. If the safepoint is GC-related |
duke@435 | 226 | // we might aggressively scan the stacks of threads that are already safe. |
duke@435 | 227 | // 3. Use Solaris schedctl to examine the state of the still-running mutators. |
duke@435 | 228 | // If all the mutators are ONPROC there's no reason to sleep or yield. |
duke@435 | 229 | // 4. YieldTo() any still-running mutators that are ready but OFFPROC. |
duke@435 | 230 | // 5. Check system saturation. If the system is not fully saturated then |
duke@435 | 231 | // simply spin and avoid sleep/yield. |
duke@435 | 232 | // 6. As still-running mutators rendezvous they could unpark the sleeping |
duke@435 | 233 | // VMthread. This works well for still-running mutators that become |
duke@435 | 234 | // safe. The VMthread must still poll for mutators that call-out. |
duke@435 | 235 | // 7. Drive the policy on time-since-begin instead of iterations. |
duke@435 | 236 | // 8. Consider making the spin duration a function of the # of CPUs: |
duke@435 | 237 | // Spin = (((ncpus-1) * M) + K) + F(still_running) |
duke@435 | 238 | // Alternately, instead of counting iterations of the outer loop |
duke@435 | 239 | // we could count the # of threads visited in the inner loop, above. |
duke@435 | 240 | // 9. On windows consider using the return value from SwitchThreadTo() |
duke@435 | 241 | // to drive subsequent spin/SwitchThreadTo()/Sleep(N) decisions. |
duke@435 | 242 | |
duke@435 | 243 | if (UseCompilerSafepoints && int(iterations) == DeferPollingPageLoopCount) { |
duke@435 | 244 | guarantee (PageArmed == 0, "invariant") ; |
duke@435 | 245 | PageArmed = 1 ; |
duke@435 | 246 | os::make_polling_page_unreadable(); |
duke@435 | 247 | } |
duke@435 | 248 | |
duke@435 | 249 | // Instead of (ncpus > 1) consider either (still_running < (ncpus + EPSILON)) or |
duke@435 | 250 | // ((still_running + _waiting_to_block - TryingToBlock)) < ncpus) |
duke@435 | 251 | ++steps ; |
duke@435 | 252 | if (ncpus > 1 && steps < SafepointSpinBeforeYield) { |
duke@435 | 253 | SpinPause() ; // MP-Polite spin |
duke@435 | 254 | } else |
duke@435 | 255 | if (steps < DeferThrSuspendLoopCount) { |
duke@435 | 256 | os::NakedYield() ; |
duke@435 | 257 | } else { |
duke@435 | 258 | os::yield_all(steps) ; |
duke@435 | 259 | // Alternately, the VM thread could transiently depress its scheduling priority or |
duke@435 | 260 | // transiently increase the priority of the tardy mutator(s). |
duke@435 | 261 | } |
duke@435 | 262 | |
duke@435 | 263 | iterations ++ ; |
duke@435 | 264 | } |
duke@435 | 265 | assert(iterations < (uint)max_jint, "We have been iterating in the safepoint loop too long"); |
duke@435 | 266 | } |
duke@435 | 267 | assert(still_running == 0, "sanity check"); |
duke@435 | 268 | |
duke@435 | 269 | if (PrintSafepointStatistics) { |
duke@435 | 270 | update_statistics_on_spin_end(); |
duke@435 | 271 | } |
duke@435 | 272 | |
duke@435 | 273 | // wait until all threads are stopped |
duke@435 | 274 | while (_waiting_to_block > 0) { |
duke@435 | 275 | if (TraceSafepoint) tty->print_cr("Waiting for %d thread(s) to block", _waiting_to_block); |
duke@435 | 276 | if (!SafepointTimeout || timeout_error_printed) { |
duke@435 | 277 | Safepoint_lock->wait(true); // true, means with no safepoint checks |
duke@435 | 278 | } else { |
duke@435 | 279 | // Compute remaining time |
duke@435 | 280 | jlong remaining_time = safepoint_limit_time - os::javaTimeNanos(); |
duke@435 | 281 | |
duke@435 | 282 | // If there is no remaining time, then there is an error |
duke@435 | 283 | if (remaining_time < 0 || Safepoint_lock->wait(true, remaining_time / MICROUNITS)) { |
duke@435 | 284 | print_safepoint_timeout(_blocking_timeout); |
duke@435 | 285 | } |
duke@435 | 286 | } |
duke@435 | 287 | } |
duke@435 | 288 | assert(_waiting_to_block == 0, "sanity check"); |
duke@435 | 289 | |
duke@435 | 290 | #ifndef PRODUCT |
duke@435 | 291 | if (SafepointTimeout) { |
duke@435 | 292 | jlong current_time = os::javaTimeNanos(); |
duke@435 | 293 | if (safepoint_limit_time < current_time) { |
duke@435 | 294 | tty->print_cr("# SafepointSynchronize: Finished after " |
duke@435 | 295 | INT64_FORMAT_W(6) " ms", |
duke@435 | 296 | ((current_time - safepoint_limit_time) / MICROUNITS + |
duke@435 | 297 | SafepointTimeoutDelay)); |
duke@435 | 298 | } |
duke@435 | 299 | } |
duke@435 | 300 | #endif |
duke@435 | 301 | |
duke@435 | 302 | assert((_safepoint_counter & 0x1) == 0, "must be even"); |
duke@435 | 303 | assert(Threads_lock->owned_by_self(), "must hold Threads_lock"); |
duke@435 | 304 | _safepoint_counter ++; |
duke@435 | 305 | |
duke@435 | 306 | // Record state |
duke@435 | 307 | _state = _synchronized; |
duke@435 | 308 | |
duke@435 | 309 | OrderAccess::fence(); |
duke@435 | 310 | |
duke@435 | 311 | if (TraceSafepoint) { |
duke@435 | 312 | VM_Operation *op = VMThread::vm_operation(); |
duke@435 | 313 | tty->print_cr("Entering safepoint region: %s", (op != NULL) ? op->name() : "no vm operation"); |
duke@435 | 314 | } |
duke@435 | 315 | |
duke@435 | 316 | RuntimeService::record_safepoint_synchronized(); |
duke@435 | 317 | if (PrintSafepointStatistics) { |
duke@435 | 318 | update_statistics_on_sync_end(os::javaTimeNanos()); |
duke@435 | 319 | } |
duke@435 | 320 | |
duke@435 | 321 | // Call stuff that needs to be run when a safepoint is just about to be completed |
duke@435 | 322 | do_cleanup_tasks(); |
duke@435 | 323 | } |
duke@435 | 324 | } |
duke@435 | 325 | |
duke@435 | 326 | // Wake up all threads, so they are ready to resume execution after the safepoint |
duke@435 | 327 | // operation has been carried out |
duke@435 | 328 | void SafepointSynchronize::end() { |
duke@435 | 329 | |
duke@435 | 330 | assert(Threads_lock->owned_by_self(), "must hold Threads_lock"); |
duke@435 | 331 | assert((_safepoint_counter & 0x1) == 1, "must be odd"); |
duke@435 | 332 | _safepoint_counter ++; |
duke@435 | 333 | // memory fence isn't required here since an odd _safepoint_counter |
duke@435 | 334 | // value can do no harm and a fence is issued below anyway. |
duke@435 | 335 | |
duke@435 | 336 | DEBUG_ONLY(Thread* myThread = Thread::current();) |
duke@435 | 337 | assert(myThread->is_VM_thread(), "Only VM thread can execute a safepoint"); |
duke@435 | 338 | |
duke@435 | 339 | if (PrintSafepointStatistics) { |
duke@435 | 340 | end_statistics(os::javaTimeNanos()); |
duke@435 | 341 | } |
duke@435 | 342 | |
duke@435 | 343 | #ifdef ASSERT |
duke@435 | 344 | // A pending_exception cannot be installed during a safepoint. The threads |
duke@435 | 345 | // may install an async exception after they come back from a safepoint into |
duke@435 | 346 | // pending_exception after they unblock. But that should happen later. |
duke@435 | 347 | for(JavaThread *cur = Threads::first(); cur; cur = cur->next()) { |
duke@435 | 348 | assert (!(cur->has_pending_exception() && |
duke@435 | 349 | cur->safepoint_state()->is_at_poll_safepoint()), |
duke@435 | 350 | "safepoint installed a pending exception"); |
duke@435 | 351 | } |
duke@435 | 352 | #endif // ASSERT |
duke@435 | 353 | |
duke@435 | 354 | if (PageArmed) { |
duke@435 | 355 | // Make polling safepoint aware |
duke@435 | 356 | os::make_polling_page_readable(); |
duke@435 | 357 | PageArmed = 0 ; |
duke@435 | 358 | } |
duke@435 | 359 | |
duke@435 | 360 | // Remove safepoint check from interpreter |
duke@435 | 361 | Interpreter::ignore_safepoints(); |
duke@435 | 362 | |
duke@435 | 363 | { |
duke@435 | 364 | MutexLocker mu(Safepoint_lock); |
duke@435 | 365 | |
duke@435 | 366 | assert(_state == _synchronized, "must be synchronized before ending safepoint synchronization"); |
duke@435 | 367 | |
duke@435 | 368 | // Set to not synchronized, so the threads will not go into the signal_thread_blocked method |
duke@435 | 369 | // when they get restarted. |
duke@435 | 370 | _state = _not_synchronized; |
duke@435 | 371 | OrderAccess::fence(); |
duke@435 | 372 | |
duke@435 | 373 | if (TraceSafepoint) { |
duke@435 | 374 | tty->print_cr("Leaving safepoint region"); |
duke@435 | 375 | } |
duke@435 | 376 | |
duke@435 | 377 | // Start suspended threads |
duke@435 | 378 | for(JavaThread *current = Threads::first(); current; current = current->next()) { |
twisti@1040 | 379 | // A problem occurring on Solaris is when attempting to restart threads |
duke@435 | 380 | // the first #cpus - 1 go well, but then the VMThread is preempted when we get |
duke@435 | 381 | // to the next one (since it has been running the longest). We then have |
duke@435 | 382 | // to wait for a cpu to become available before we can continue restarting |
duke@435 | 383 | // threads. |
duke@435 | 384 | // FIXME: This causes the performance of the VM to degrade when active and with |
duke@435 | 385 | // large numbers of threads. Apparently this is due to the synchronous nature |
duke@435 | 386 | // of suspending threads. |
duke@435 | 387 | // |
duke@435 | 388 | // TODO-FIXME: the comments above are vestigial and no longer apply. |
duke@435 | 389 | // Furthermore, using solaris' schedctl in this particular context confers no benefit |
duke@435 | 390 | if (VMThreadHintNoPreempt) { |
duke@435 | 391 | os::hint_no_preempt(); |
duke@435 | 392 | } |
duke@435 | 393 | ThreadSafepointState* cur_state = current->safepoint_state(); |
duke@435 | 394 | assert(cur_state->type() != ThreadSafepointState::_running, "Thread not suspended at safepoint"); |
duke@435 | 395 | cur_state->restart(); |
duke@435 | 396 | assert(cur_state->is_running(), "safepoint state has not been reset"); |
duke@435 | 397 | } |
duke@435 | 398 | |
duke@435 | 399 | RuntimeService::record_safepoint_end(); |
duke@435 | 400 | |
duke@435 | 401 | // Release threads lock, so threads can be created/destroyed again. It will also starts all threads |
duke@435 | 402 | // blocked in signal_thread_blocked |
duke@435 | 403 | Threads_lock->unlock(); |
duke@435 | 404 | |
duke@435 | 405 | } |
duke@435 | 406 | #ifndef SERIALGC |
duke@435 | 407 | // If there are any concurrent GC threads resume them. |
duke@435 | 408 | if (UseConcMarkSweepGC) { |
duke@435 | 409 | ConcurrentMarkSweepThread::desynchronize(false); |
ysr@1280 | 410 | } else if (UseG1GC) { |
duke@435 | 411 | ConcurrentGCThread::safepoint_desynchronize(); |
duke@435 | 412 | } |
duke@435 | 413 | #endif // SERIALGC |
duke@435 | 414 | } |
duke@435 | 415 | |
duke@435 | 416 | bool SafepointSynchronize::is_cleanup_needed() { |
duke@435 | 417 | // Need a safepoint if some inline cache buffers is non-empty |
duke@435 | 418 | if (!InlineCacheBuffer::is_empty()) return true; |
duke@435 | 419 | return false; |
duke@435 | 420 | } |
duke@435 | 421 | |
duke@435 | 422 | jlong CounterDecay::_last_timestamp = 0; |
duke@435 | 423 | |
duke@435 | 424 | static void do_method(methodOop m) { |
duke@435 | 425 | m->invocation_counter()->decay(); |
duke@435 | 426 | } |
duke@435 | 427 | |
duke@435 | 428 | void CounterDecay::decay() { |
duke@435 | 429 | _last_timestamp = os::javaTimeMillis(); |
duke@435 | 430 | |
duke@435 | 431 | // This operation is going to be performed only at the end of a safepoint |
duke@435 | 432 | // and hence GC's will not be going on, all Java mutators are suspended |
duke@435 | 433 | // at this point and hence SystemDictionary_lock is also not needed. |
duke@435 | 434 | assert(SafepointSynchronize::is_at_safepoint(), "can only be executed at a safepoint"); |
duke@435 | 435 | int nclasses = SystemDictionary::number_of_classes(); |
duke@435 | 436 | double classes_per_tick = nclasses * (CounterDecayMinIntervalLength * 1e-3 / |
duke@435 | 437 | CounterHalfLifeTime); |
duke@435 | 438 | for (int i = 0; i < classes_per_tick; i++) { |
duke@435 | 439 | klassOop k = SystemDictionary::try_get_next_class(); |
duke@435 | 440 | if (k != NULL && k->klass_part()->oop_is_instance()) { |
duke@435 | 441 | instanceKlass::cast(k)->methods_do(do_method); |
duke@435 | 442 | } |
duke@435 | 443 | } |
duke@435 | 444 | } |
duke@435 | 445 | |
duke@435 | 446 | // Various cleaning tasks that should be done periodically at safepoints |
duke@435 | 447 | void SafepointSynchronize::do_cleanup_tasks() { |
duke@435 | 448 | jlong cleanup_time; |
duke@435 | 449 | |
duke@435 | 450 | // Update fat-monitor pool, since this is a safepoint. |
duke@435 | 451 | if (TraceSafepoint) { |
duke@435 | 452 | cleanup_time = os::javaTimeNanos(); |
duke@435 | 453 | } |
duke@435 | 454 | |
duke@435 | 455 | ObjectSynchronizer::deflate_idle_monitors(); |
duke@435 | 456 | InlineCacheBuffer::update_inline_caches(); |
duke@435 | 457 | if(UseCounterDecay && CounterDecay::is_decay_needed()) { |
duke@435 | 458 | CounterDecay::decay(); |
duke@435 | 459 | } |
duke@435 | 460 | NMethodSweeper::sweep(); |
duke@435 | 461 | |
duke@435 | 462 | if (TraceSafepoint) { |
duke@435 | 463 | tty->print_cr("do_cleanup_tasks takes "INT64_FORMAT_W(6) "ms", |
duke@435 | 464 | (os::javaTimeNanos() - cleanup_time) / MICROUNITS); |
duke@435 | 465 | } |
duke@435 | 466 | } |
duke@435 | 467 | |
duke@435 | 468 | |
duke@435 | 469 | bool SafepointSynchronize::safepoint_safe(JavaThread *thread, JavaThreadState state) { |
duke@435 | 470 | switch(state) { |
duke@435 | 471 | case _thread_in_native: |
duke@435 | 472 | // native threads are safe if they have no java stack or have walkable stack |
duke@435 | 473 | return !thread->has_last_Java_frame() || thread->frame_anchor()->walkable(); |
duke@435 | 474 | |
duke@435 | 475 | // blocked threads should have already have walkable stack |
duke@435 | 476 | case _thread_blocked: |
duke@435 | 477 | assert(!thread->has_last_Java_frame() || thread->frame_anchor()->walkable(), "blocked and not walkable"); |
duke@435 | 478 | return true; |
duke@435 | 479 | |
duke@435 | 480 | default: |
duke@435 | 481 | return false; |
duke@435 | 482 | } |
duke@435 | 483 | } |
duke@435 | 484 | |
duke@435 | 485 | |
duke@435 | 486 | // ------------------------------------------------------------------------------------------------------- |
duke@435 | 487 | // Implementation of Safepoint callback point |
duke@435 | 488 | |
duke@435 | 489 | void SafepointSynchronize::block(JavaThread *thread) { |
duke@435 | 490 | assert(thread != NULL, "thread must be set"); |
duke@435 | 491 | assert(thread->is_Java_thread(), "not a Java thread"); |
duke@435 | 492 | |
duke@435 | 493 | // Threads shouldn't block if they are in the middle of printing, but... |
duke@435 | 494 | ttyLocker::break_tty_lock_for_safepoint(os::current_thread_id()); |
duke@435 | 495 | |
duke@435 | 496 | // Only bail from the block() call if the thread is gone from the |
duke@435 | 497 | // thread list; starting to exit should still block. |
duke@435 | 498 | if (thread->is_terminated()) { |
duke@435 | 499 | // block current thread if we come here from native code when VM is gone |
duke@435 | 500 | thread->block_if_vm_exited(); |
duke@435 | 501 | |
duke@435 | 502 | // otherwise do nothing |
duke@435 | 503 | return; |
duke@435 | 504 | } |
duke@435 | 505 | |
duke@435 | 506 | JavaThreadState state = thread->thread_state(); |
duke@435 | 507 | thread->frame_anchor()->make_walkable(thread); |
duke@435 | 508 | |
duke@435 | 509 | // Check that we have a valid thread_state at this point |
duke@435 | 510 | switch(state) { |
duke@435 | 511 | case _thread_in_vm_trans: |
duke@435 | 512 | case _thread_in_Java: // From compiled code |
duke@435 | 513 | |
duke@435 | 514 | // We are highly likely to block on the Safepoint_lock. In order to avoid blocking in this case, |
duke@435 | 515 | // we pretend we are still in the VM. |
duke@435 | 516 | thread->set_thread_state(_thread_in_vm); |
duke@435 | 517 | |
duke@435 | 518 | if (is_synchronizing()) { |
duke@435 | 519 | Atomic::inc (&TryingToBlock) ; |
duke@435 | 520 | } |
duke@435 | 521 | |
duke@435 | 522 | // We will always be holding the Safepoint_lock when we are examine the state |
duke@435 | 523 | // of a thread. Hence, the instructions between the Safepoint_lock->lock() and |
duke@435 | 524 | // Safepoint_lock->unlock() are happening atomic with regards to the safepoint code |
duke@435 | 525 | Safepoint_lock->lock_without_safepoint_check(); |
duke@435 | 526 | if (is_synchronizing()) { |
duke@435 | 527 | // Decrement the number of threads to wait for and signal vm thread |
duke@435 | 528 | assert(_waiting_to_block > 0, "sanity check"); |
duke@435 | 529 | _waiting_to_block--; |
duke@435 | 530 | thread->safepoint_state()->set_has_called_back(true); |
duke@435 | 531 | |
duke@435 | 532 | // Consider (_waiting_to_block < 2) to pipeline the wakeup of the VM thread |
duke@435 | 533 | if (_waiting_to_block == 0) { |
duke@435 | 534 | Safepoint_lock->notify_all(); |
duke@435 | 535 | } |
duke@435 | 536 | } |
duke@435 | 537 | |
duke@435 | 538 | // We transition the thread to state _thread_blocked here, but |
duke@435 | 539 | // we can't do our usual check for external suspension and then |
duke@435 | 540 | // self-suspend after the lock_without_safepoint_check() call |
duke@435 | 541 | // below because we are often called during transitions while |
duke@435 | 542 | // we hold different locks. That would leave us suspended while |
duke@435 | 543 | // holding a resource which results in deadlocks. |
duke@435 | 544 | thread->set_thread_state(_thread_blocked); |
duke@435 | 545 | Safepoint_lock->unlock(); |
duke@435 | 546 | |
duke@435 | 547 | // We now try to acquire the threads lock. Since this lock is hold by the VM thread during |
duke@435 | 548 | // the entire safepoint, the threads will all line up here during the safepoint. |
duke@435 | 549 | Threads_lock->lock_without_safepoint_check(); |
duke@435 | 550 | // restore original state. This is important if the thread comes from compiled code, so it |
duke@435 | 551 | // will continue to execute with the _thread_in_Java state. |
duke@435 | 552 | thread->set_thread_state(state); |
duke@435 | 553 | Threads_lock->unlock(); |
duke@435 | 554 | break; |
duke@435 | 555 | |
duke@435 | 556 | case _thread_in_native_trans: |
duke@435 | 557 | case _thread_blocked_trans: |
duke@435 | 558 | case _thread_new_trans: |
duke@435 | 559 | if (thread->safepoint_state()->type() == ThreadSafepointState::_call_back) { |
duke@435 | 560 | thread->print_thread_state(); |
duke@435 | 561 | fatal("Deadlock in safepoint code. " |
duke@435 | 562 | "Should have called back to the VM before blocking."); |
duke@435 | 563 | } |
duke@435 | 564 | |
duke@435 | 565 | // We transition the thread to state _thread_blocked here, but |
duke@435 | 566 | // we can't do our usual check for external suspension and then |
duke@435 | 567 | // self-suspend after the lock_without_safepoint_check() call |
duke@435 | 568 | // below because we are often called during transitions while |
duke@435 | 569 | // we hold different locks. That would leave us suspended while |
duke@435 | 570 | // holding a resource which results in deadlocks. |
duke@435 | 571 | thread->set_thread_state(_thread_blocked); |
duke@435 | 572 | |
duke@435 | 573 | // It is not safe to suspend a thread if we discover it is in _thread_in_native_trans. Hence, |
duke@435 | 574 | // the safepoint code might still be waiting for it to block. We need to change the state here, |
duke@435 | 575 | // so it can see that it is at a safepoint. |
duke@435 | 576 | |
duke@435 | 577 | // Block until the safepoint operation is completed. |
duke@435 | 578 | Threads_lock->lock_without_safepoint_check(); |
duke@435 | 579 | |
duke@435 | 580 | // Restore state |
duke@435 | 581 | thread->set_thread_state(state); |
duke@435 | 582 | |
duke@435 | 583 | Threads_lock->unlock(); |
duke@435 | 584 | break; |
duke@435 | 585 | |
duke@435 | 586 | default: |
duke@435 | 587 | fatal1("Illegal threadstate encountered: %d", state); |
duke@435 | 588 | } |
duke@435 | 589 | |
duke@435 | 590 | // Check for pending. async. exceptions or suspends - except if the |
duke@435 | 591 | // thread was blocked inside the VM. has_special_runtime_exit_condition() |
duke@435 | 592 | // is called last since it grabs a lock and we only want to do that when |
duke@435 | 593 | // we must. |
duke@435 | 594 | // |
duke@435 | 595 | // Note: we never deliver an async exception at a polling point as the |
duke@435 | 596 | // compiler may not have an exception handler for it. The polling |
duke@435 | 597 | // code will notice the async and deoptimize and the exception will |
duke@435 | 598 | // be delivered. (Polling at a return point is ok though). Sure is |
duke@435 | 599 | // a lot of bother for a deprecated feature... |
duke@435 | 600 | // |
duke@435 | 601 | // We don't deliver an async exception if the thread state is |
duke@435 | 602 | // _thread_in_native_trans so JNI functions won't be called with |
duke@435 | 603 | // a surprising pending exception. If the thread state is going back to java, |
duke@435 | 604 | // async exception is checked in check_special_condition_for_native_trans(). |
duke@435 | 605 | |
duke@435 | 606 | if (state != _thread_blocked_trans && |
duke@435 | 607 | state != _thread_in_vm_trans && |
duke@435 | 608 | thread->has_special_runtime_exit_condition()) { |
duke@435 | 609 | thread->handle_special_runtime_exit_condition( |
duke@435 | 610 | !thread->is_at_poll_safepoint() && (state != _thread_in_native_trans)); |
duke@435 | 611 | } |
duke@435 | 612 | } |
duke@435 | 613 | |
duke@435 | 614 | // ------------------------------------------------------------------------------------------------------ |
duke@435 | 615 | // Exception handlers |
duke@435 | 616 | |
duke@435 | 617 | #ifndef PRODUCT |
duke@435 | 618 | #ifdef _LP64 |
duke@435 | 619 | #define PTR_PAD "" |
duke@435 | 620 | #else |
duke@435 | 621 | #define PTR_PAD " " |
duke@435 | 622 | #endif |
duke@435 | 623 | |
duke@435 | 624 | static void print_ptrs(intptr_t oldptr, intptr_t newptr, bool wasoop) { |
duke@435 | 625 | bool is_oop = newptr ? ((oop)newptr)->is_oop() : false; |
duke@435 | 626 | tty->print_cr(PTR_FORMAT PTR_PAD " %s %c " PTR_FORMAT PTR_PAD " %s %s", |
duke@435 | 627 | oldptr, wasoop?"oop":" ", oldptr == newptr ? ' ' : '!', |
duke@435 | 628 | newptr, is_oop?"oop":" ", (wasoop && !is_oop) ? "STALE" : ((wasoop==false&&is_oop==false&&oldptr !=newptr)?"STOMP":" ")); |
duke@435 | 629 | } |
duke@435 | 630 | |
duke@435 | 631 | static void print_longs(jlong oldptr, jlong newptr, bool wasoop) { |
duke@435 | 632 | bool is_oop = newptr ? ((oop)(intptr_t)newptr)->is_oop() : false; |
duke@435 | 633 | tty->print_cr(PTR64_FORMAT " %s %c " PTR64_FORMAT " %s %s", |
duke@435 | 634 | oldptr, wasoop?"oop":" ", oldptr == newptr ? ' ' : '!', |
duke@435 | 635 | newptr, is_oop?"oop":" ", (wasoop && !is_oop) ? "STALE" : ((wasoop==false&&is_oop==false&&oldptr !=newptr)?"STOMP":" ")); |
duke@435 | 636 | } |
duke@435 | 637 | |
duke@435 | 638 | #ifdef SPARC |
duke@435 | 639 | static void print_me(intptr_t *new_sp, intptr_t *old_sp, bool *was_oops) { |
duke@435 | 640 | #ifdef _LP64 |
duke@435 | 641 | tty->print_cr("--------+------address-----+------before-----------+-------after----------+"); |
duke@435 | 642 | const int incr = 1; // Increment to skip a long, in units of intptr_t |
duke@435 | 643 | #else |
duke@435 | 644 | tty->print_cr("--------+--address-+------before-----------+-------after----------+"); |
duke@435 | 645 | const int incr = 2; // Increment to skip a long, in units of intptr_t |
duke@435 | 646 | #endif |
duke@435 | 647 | tty->print_cr("---SP---|"); |
duke@435 | 648 | for( int i=0; i<16; i++ ) { |
duke@435 | 649 | tty->print("blob %c%d |"PTR_FORMAT" ","LO"[i>>3],i&7,new_sp); print_ptrs(*old_sp++,*new_sp++,*was_oops++); } |
duke@435 | 650 | tty->print_cr("--------|"); |
duke@435 | 651 | for( int i1=0; i1<frame::memory_parameter_word_sp_offset-16; i1++ ) { |
duke@435 | 652 | tty->print("argv pad|"PTR_FORMAT" ",new_sp); print_ptrs(*old_sp++,*new_sp++,*was_oops++); } |
duke@435 | 653 | tty->print(" pad|"PTR_FORMAT" ",new_sp); print_ptrs(*old_sp++,*new_sp++,*was_oops++); |
duke@435 | 654 | tty->print_cr("--------|"); |
duke@435 | 655 | 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; |
duke@435 | 656 | 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; |
duke@435 | 657 | 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; |
duke@435 | 658 | 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; |
duke@435 | 659 | tty->print_cr(" FSR |"PTR_FORMAT" "PTR64_FORMAT" "PTR64_FORMAT,new_sp,*(jlong*)old_sp,*(jlong*)new_sp); |
duke@435 | 660 | old_sp += incr; new_sp += incr; was_oops += incr; |
duke@435 | 661 | // Skip the floats |
duke@435 | 662 | tty->print_cr("--Float-|"PTR_FORMAT,new_sp); |
duke@435 | 663 | tty->print_cr("---FP---|"); |
duke@435 | 664 | old_sp += incr*32; new_sp += incr*32; was_oops += incr*32; |
duke@435 | 665 | for( int i2=0; i2<16; i2++ ) { |
duke@435 | 666 | tty->print("call %c%d |"PTR_FORMAT" ","LI"[i2>>3],i2&7,new_sp); print_ptrs(*old_sp++,*new_sp++,*was_oops++); } |
duke@435 | 667 | tty->print_cr(""); |
duke@435 | 668 | } |
duke@435 | 669 | #endif // SPARC |
duke@435 | 670 | #endif // PRODUCT |
duke@435 | 671 | |
duke@435 | 672 | |
duke@435 | 673 | void SafepointSynchronize::handle_polling_page_exception(JavaThread *thread) { |
duke@435 | 674 | assert(thread->is_Java_thread(), "polling reference encountered by VM thread"); |
duke@435 | 675 | assert(thread->thread_state() == _thread_in_Java, "should come from Java code"); |
duke@435 | 676 | assert(SafepointSynchronize::is_synchronizing(), "polling encountered outside safepoint synchronization"); |
duke@435 | 677 | |
duke@435 | 678 | // Uncomment this to get some serious before/after printing of the |
duke@435 | 679 | // Sparc safepoint-blob frame structure. |
duke@435 | 680 | /* |
duke@435 | 681 | intptr_t* sp = thread->last_Java_sp(); |
duke@435 | 682 | intptr_t stack_copy[150]; |
duke@435 | 683 | for( int i=0; i<150; i++ ) stack_copy[i] = sp[i]; |
duke@435 | 684 | bool was_oops[150]; |
duke@435 | 685 | for( int i=0; i<150; i++ ) |
duke@435 | 686 | was_oops[i] = stack_copy[i] ? ((oop)stack_copy[i])->is_oop() : false; |
duke@435 | 687 | */ |
duke@435 | 688 | |
duke@435 | 689 | if (ShowSafepointMsgs) { |
duke@435 | 690 | tty->print("handle_polling_page_exception: "); |
duke@435 | 691 | } |
duke@435 | 692 | |
duke@435 | 693 | if (PrintSafepointStatistics) { |
duke@435 | 694 | inc_page_trap_count(); |
duke@435 | 695 | } |
duke@435 | 696 | |
duke@435 | 697 | ThreadSafepointState* state = thread->safepoint_state(); |
duke@435 | 698 | |
duke@435 | 699 | state->handle_polling_page_exception(); |
duke@435 | 700 | // print_me(sp,stack_copy,was_oops); |
duke@435 | 701 | } |
duke@435 | 702 | |
duke@435 | 703 | |
duke@435 | 704 | void SafepointSynchronize::print_safepoint_timeout(SafepointTimeoutReason reason) { |
duke@435 | 705 | if (!timeout_error_printed) { |
duke@435 | 706 | timeout_error_printed = true; |
duke@435 | 707 | // Print out the thread infor which didn't reach the safepoint for debugging |
duke@435 | 708 | // purposes (useful when there are lots of threads in the debugger). |
duke@435 | 709 | tty->print_cr(""); |
duke@435 | 710 | tty->print_cr("# SafepointSynchronize::begin: Timeout detected:"); |
duke@435 | 711 | if (reason == _spinning_timeout) { |
duke@435 | 712 | tty->print_cr("# SafepointSynchronize::begin: Timed out while spinning to reach a safepoint."); |
duke@435 | 713 | } else if (reason == _blocking_timeout) { |
duke@435 | 714 | tty->print_cr("# SafepointSynchronize::begin: Timed out while waiting for threads to stop."); |
duke@435 | 715 | } |
duke@435 | 716 | |
duke@435 | 717 | tty->print_cr("# SafepointSynchronize::begin: Threads which did not reach the safepoint:"); |
duke@435 | 718 | ThreadSafepointState *cur_state; |
duke@435 | 719 | ResourceMark rm; |
duke@435 | 720 | for(JavaThread *cur_thread = Threads::first(); cur_thread; |
duke@435 | 721 | cur_thread = cur_thread->next()) { |
duke@435 | 722 | cur_state = cur_thread->safepoint_state(); |
duke@435 | 723 | |
duke@435 | 724 | if (cur_thread->thread_state() != _thread_blocked && |
duke@435 | 725 | ((reason == _spinning_timeout && cur_state->is_running()) || |
duke@435 | 726 | (reason == _blocking_timeout && !cur_state->has_called_back()))) { |
duke@435 | 727 | tty->print("# "); |
duke@435 | 728 | cur_thread->print(); |
duke@435 | 729 | tty->print_cr(""); |
duke@435 | 730 | } |
duke@435 | 731 | } |
duke@435 | 732 | tty->print_cr("# SafepointSynchronize::begin: (End of list)"); |
duke@435 | 733 | } |
duke@435 | 734 | |
duke@435 | 735 | // To debug the long safepoint, specify both DieOnSafepointTimeout & |
duke@435 | 736 | // ShowMessageBoxOnError. |
duke@435 | 737 | if (DieOnSafepointTimeout) { |
duke@435 | 738 | char msg[1024]; |
duke@435 | 739 | VM_Operation *op = VMThread::vm_operation(); |
xlu@948 | 740 | sprintf(msg, "Safepoint sync time longer than " INTX_FORMAT "ms detected when executing %s.", |
duke@435 | 741 | SafepointTimeoutDelay, |
duke@435 | 742 | op != NULL ? op->name() : "no vm operation"); |
duke@435 | 743 | fatal(msg); |
duke@435 | 744 | } |
duke@435 | 745 | } |
duke@435 | 746 | |
duke@435 | 747 | |
duke@435 | 748 | // ------------------------------------------------------------------------------------------------------- |
duke@435 | 749 | // Implementation of ThreadSafepointState |
duke@435 | 750 | |
duke@435 | 751 | ThreadSafepointState::ThreadSafepointState(JavaThread *thread) { |
duke@435 | 752 | _thread = thread; |
duke@435 | 753 | _type = _running; |
duke@435 | 754 | _has_called_back = false; |
duke@435 | 755 | _at_poll_safepoint = false; |
duke@435 | 756 | } |
duke@435 | 757 | |
duke@435 | 758 | void ThreadSafepointState::create(JavaThread *thread) { |
duke@435 | 759 | ThreadSafepointState *state = new ThreadSafepointState(thread); |
duke@435 | 760 | thread->set_safepoint_state(state); |
duke@435 | 761 | } |
duke@435 | 762 | |
duke@435 | 763 | void ThreadSafepointState::destroy(JavaThread *thread) { |
duke@435 | 764 | if (thread->safepoint_state()) { |
duke@435 | 765 | delete(thread->safepoint_state()); |
duke@435 | 766 | thread->set_safepoint_state(NULL); |
duke@435 | 767 | } |
duke@435 | 768 | } |
duke@435 | 769 | |
duke@435 | 770 | void ThreadSafepointState::examine_state_of_thread() { |
duke@435 | 771 | assert(is_running(), "better be running or just have hit safepoint poll"); |
duke@435 | 772 | |
duke@435 | 773 | JavaThreadState state = _thread->thread_state(); |
duke@435 | 774 | |
duke@435 | 775 | // Check for a thread that is suspended. Note that thread resume tries |
duke@435 | 776 | // to grab the Threads_lock which we own here, so a thread cannot be |
duke@435 | 777 | // resumed during safepoint synchronization. |
duke@435 | 778 | |
dcubed@1414 | 779 | // We check to see if this thread is suspended without locking to |
dcubed@1414 | 780 | // avoid deadlocking with a third thread that is waiting for this |
dcubed@1414 | 781 | // thread to be suspended. The third thread can notice the safepoint |
dcubed@1414 | 782 | // that we're trying to start at the beginning of its SR_lock->wait() |
dcubed@1414 | 783 | // call. If that happens, then the third thread will block on the |
dcubed@1414 | 784 | // safepoint while still holding the underlying SR_lock. We won't be |
dcubed@1414 | 785 | // able to get the SR_lock and we'll deadlock. |
dcubed@1414 | 786 | // |
dcubed@1414 | 787 | // We don't need to grab the SR_lock here for two reasons: |
dcubed@1414 | 788 | // 1) The suspend flags are both volatile and are set with an |
dcubed@1414 | 789 | // Atomic::cmpxchg() call so we should see the suspended |
dcubed@1414 | 790 | // state right away. |
dcubed@1414 | 791 | // 2) We're being called from the safepoint polling loop; if |
dcubed@1414 | 792 | // we don't see the suspended state on this iteration, then |
dcubed@1414 | 793 | // we'll come around again. |
dcubed@1414 | 794 | // |
dcubed@1414 | 795 | bool is_suspended = _thread->is_ext_suspended(); |
duke@435 | 796 | if (is_suspended) { |
duke@435 | 797 | roll_forward(_at_safepoint); |
duke@435 | 798 | return; |
duke@435 | 799 | } |
duke@435 | 800 | |
duke@435 | 801 | // Some JavaThread states have an initial safepoint state of |
duke@435 | 802 | // running, but are actually at a safepoint. We will happily |
duke@435 | 803 | // agree and update the safepoint state here. |
duke@435 | 804 | if (SafepointSynchronize::safepoint_safe(_thread, state)) { |
duke@435 | 805 | roll_forward(_at_safepoint); |
duke@435 | 806 | return; |
duke@435 | 807 | } |
duke@435 | 808 | |
duke@435 | 809 | if (state == _thread_in_vm) { |
duke@435 | 810 | roll_forward(_call_back); |
duke@435 | 811 | return; |
duke@435 | 812 | } |
duke@435 | 813 | |
duke@435 | 814 | // All other thread states will continue to run until they |
duke@435 | 815 | // transition and self-block in state _blocked |
duke@435 | 816 | // Safepoint polling in compiled code causes the Java threads to do the same. |
duke@435 | 817 | // Note: new threads may require a malloc so they must be allowed to finish |
duke@435 | 818 | |
duke@435 | 819 | assert(is_running(), "examine_state_of_thread on non-running thread"); |
duke@435 | 820 | return; |
duke@435 | 821 | } |
duke@435 | 822 | |
duke@435 | 823 | // Returns true is thread could not be rolled forward at present position. |
duke@435 | 824 | void ThreadSafepointState::roll_forward(suspend_type type) { |
duke@435 | 825 | _type = type; |
duke@435 | 826 | |
duke@435 | 827 | switch(_type) { |
duke@435 | 828 | case _at_safepoint: |
duke@435 | 829 | SafepointSynchronize::signal_thread_at_safepoint(); |
duke@435 | 830 | break; |
duke@435 | 831 | |
duke@435 | 832 | case _call_back: |
duke@435 | 833 | set_has_called_back(false); |
duke@435 | 834 | break; |
duke@435 | 835 | |
duke@435 | 836 | case _running: |
duke@435 | 837 | default: |
duke@435 | 838 | ShouldNotReachHere(); |
duke@435 | 839 | } |
duke@435 | 840 | } |
duke@435 | 841 | |
duke@435 | 842 | void ThreadSafepointState::restart() { |
duke@435 | 843 | switch(type()) { |
duke@435 | 844 | case _at_safepoint: |
duke@435 | 845 | case _call_back: |
duke@435 | 846 | break; |
duke@435 | 847 | |
duke@435 | 848 | case _running: |
duke@435 | 849 | default: |
duke@435 | 850 | tty->print_cr("restart thread "INTPTR_FORMAT" with state %d", |
duke@435 | 851 | _thread, _type); |
duke@435 | 852 | _thread->print(); |
duke@435 | 853 | ShouldNotReachHere(); |
duke@435 | 854 | } |
duke@435 | 855 | _type = _running; |
duke@435 | 856 | set_has_called_back(false); |
duke@435 | 857 | } |
duke@435 | 858 | |
duke@435 | 859 | |
duke@435 | 860 | void ThreadSafepointState::print_on(outputStream *st) const { |
duke@435 | 861 | const char *s; |
duke@435 | 862 | |
duke@435 | 863 | switch(_type) { |
duke@435 | 864 | case _running : s = "_running"; break; |
duke@435 | 865 | case _at_safepoint : s = "_at_safepoint"; break; |
duke@435 | 866 | case _call_back : s = "_call_back"; break; |
duke@435 | 867 | default: |
duke@435 | 868 | ShouldNotReachHere(); |
duke@435 | 869 | } |
duke@435 | 870 | |
duke@435 | 871 | st->print_cr("Thread: " INTPTR_FORMAT |
duke@435 | 872 | " [0x%2x] State: %s _has_called_back %d _at_poll_safepoint %d", |
duke@435 | 873 | _thread, _thread->osthread()->thread_id(), s, _has_called_back, |
duke@435 | 874 | _at_poll_safepoint); |
duke@435 | 875 | |
duke@435 | 876 | _thread->print_thread_state_on(st); |
duke@435 | 877 | } |
duke@435 | 878 | |
duke@435 | 879 | |
duke@435 | 880 | // --------------------------------------------------------------------------------------------------------------------- |
duke@435 | 881 | |
duke@435 | 882 | // Block the thread at the safepoint poll or poll return. |
duke@435 | 883 | void ThreadSafepointState::handle_polling_page_exception() { |
duke@435 | 884 | |
duke@435 | 885 | // Check state. block() will set thread state to thread_in_vm which will |
duke@435 | 886 | // cause the safepoint state _type to become _call_back. |
duke@435 | 887 | assert(type() == ThreadSafepointState::_running, |
duke@435 | 888 | "polling page exception on thread not running state"); |
duke@435 | 889 | |
duke@435 | 890 | // Step 1: Find the nmethod from the return address |
duke@435 | 891 | if (ShowSafepointMsgs && Verbose) { |
duke@435 | 892 | tty->print_cr("Polling page exception at " INTPTR_FORMAT, thread()->saved_exception_pc()); |
duke@435 | 893 | } |
duke@435 | 894 | address real_return_addr = thread()->saved_exception_pc(); |
duke@435 | 895 | |
duke@435 | 896 | CodeBlob *cb = CodeCache::find_blob(real_return_addr); |
duke@435 | 897 | assert(cb != NULL && cb->is_nmethod(), "return address should be in nmethod"); |
duke@435 | 898 | nmethod* nm = (nmethod*)cb; |
duke@435 | 899 | |
duke@435 | 900 | // Find frame of caller |
duke@435 | 901 | frame stub_fr = thread()->last_frame(); |
duke@435 | 902 | CodeBlob* stub_cb = stub_fr.cb(); |
duke@435 | 903 | assert(stub_cb->is_safepoint_stub(), "must be a safepoint stub"); |
duke@435 | 904 | RegisterMap map(thread(), true); |
duke@435 | 905 | frame caller_fr = stub_fr.sender(&map); |
duke@435 | 906 | |
duke@435 | 907 | // Should only be poll_return or poll |
duke@435 | 908 | assert( nm->is_at_poll_or_poll_return(real_return_addr), "should not be at call" ); |
duke@435 | 909 | |
duke@435 | 910 | // This is a poll immediately before a return. The exception handling code |
duke@435 | 911 | // has already had the effect of causing the return to occur, so the execution |
duke@435 | 912 | // will continue immediately after the call. In addition, the oopmap at the |
duke@435 | 913 | // return point does not mark the return value as an oop (if it is), so |
duke@435 | 914 | // it needs a handle here to be updated. |
duke@435 | 915 | if( nm->is_at_poll_return(real_return_addr) ) { |
duke@435 | 916 | // See if return type is an oop. |
duke@435 | 917 | bool return_oop = nm->method()->is_returning_oop(); |
duke@435 | 918 | Handle return_value; |
duke@435 | 919 | if (return_oop) { |
duke@435 | 920 | // The oop result has been saved on the stack together with all |
duke@435 | 921 | // the other registers. In order to preserve it over GCs we need |
duke@435 | 922 | // to keep it in a handle. |
duke@435 | 923 | oop result = caller_fr.saved_oop_result(&map); |
duke@435 | 924 | assert(result == NULL || result->is_oop(), "must be oop"); |
duke@435 | 925 | return_value = Handle(thread(), result); |
duke@435 | 926 | assert(Universe::heap()->is_in_or_null(result), "must be heap pointer"); |
duke@435 | 927 | } |
duke@435 | 928 | |
duke@435 | 929 | // Block the thread |
duke@435 | 930 | SafepointSynchronize::block(thread()); |
duke@435 | 931 | |
duke@435 | 932 | // restore oop result, if any |
duke@435 | 933 | if (return_oop) { |
duke@435 | 934 | caller_fr.set_saved_oop_result(&map, return_value()); |
duke@435 | 935 | } |
duke@435 | 936 | } |
duke@435 | 937 | |
duke@435 | 938 | // This is a safepoint poll. Verify the return address and block. |
duke@435 | 939 | else { |
duke@435 | 940 | set_at_poll_safepoint(true); |
duke@435 | 941 | |
duke@435 | 942 | // verify the blob built the "return address" correctly |
duke@435 | 943 | assert(real_return_addr == caller_fr.pc(), "must match"); |
duke@435 | 944 | |
duke@435 | 945 | // Block the thread |
duke@435 | 946 | SafepointSynchronize::block(thread()); |
duke@435 | 947 | set_at_poll_safepoint(false); |
duke@435 | 948 | |
duke@435 | 949 | // If we have a pending async exception deoptimize the frame |
duke@435 | 950 | // as otherwise we may never deliver it. |
duke@435 | 951 | if (thread()->has_async_condition()) { |
duke@435 | 952 | ThreadInVMfromJavaNoAsyncException __tiv(thread()); |
duke@435 | 953 | VM_DeoptimizeFrame deopt(thread(), caller_fr.id()); |
duke@435 | 954 | VMThread::execute(&deopt); |
duke@435 | 955 | } |
duke@435 | 956 | |
duke@435 | 957 | // If an exception has been installed we must check for a pending deoptimization |
duke@435 | 958 | // Deoptimize frame if exception has been thrown. |
duke@435 | 959 | |
duke@435 | 960 | if (thread()->has_pending_exception() ) { |
duke@435 | 961 | RegisterMap map(thread(), true); |
duke@435 | 962 | frame caller_fr = stub_fr.sender(&map); |
duke@435 | 963 | if (caller_fr.is_deoptimized_frame()) { |
duke@435 | 964 | // The exception patch will destroy registers that are still |
duke@435 | 965 | // live and will be needed during deoptimization. Defer the |
duke@435 | 966 | // Async exception should have defered the exception until the |
duke@435 | 967 | // next safepoint which will be detected when we get into |
duke@435 | 968 | // the interpreter so if we have an exception now things |
duke@435 | 969 | // are messed up. |
duke@435 | 970 | |
duke@435 | 971 | fatal("Exception installed and deoptimization is pending"); |
duke@435 | 972 | } |
duke@435 | 973 | } |
duke@435 | 974 | } |
duke@435 | 975 | } |
duke@435 | 976 | |
duke@435 | 977 | |
duke@435 | 978 | // |
duke@435 | 979 | // Statistics & Instrumentations |
duke@435 | 980 | // |
duke@435 | 981 | SafepointSynchronize::SafepointStats* SafepointSynchronize::_safepoint_stats = NULL; |
duke@435 | 982 | int SafepointSynchronize::_cur_stat_index = 0; |
duke@435 | 983 | julong SafepointSynchronize::_safepoint_reasons[VM_Operation::VMOp_Terminating]; |
duke@435 | 984 | julong SafepointSynchronize::_coalesced_vmop_count = 0; |
duke@435 | 985 | jlong SafepointSynchronize::_max_sync_time = 0; |
duke@435 | 986 | |
duke@435 | 987 | // last_safepoint_start_time records the start time of last safepoint. |
duke@435 | 988 | static jlong last_safepoint_start_time = 0; |
duke@435 | 989 | static jlong sync_end_time = 0; |
duke@435 | 990 | static bool need_to_track_page_armed_status = false; |
duke@435 | 991 | static bool init_done = false; |
duke@435 | 992 | |
duke@435 | 993 | void SafepointSynchronize::deferred_initialize_stat() { |
duke@435 | 994 | if (init_done) return; |
duke@435 | 995 | |
duke@435 | 996 | if (PrintSafepointStatisticsCount <= 0) { |
duke@435 | 997 | fatal("Wrong PrintSafepointStatisticsCount"); |
duke@435 | 998 | } |
duke@435 | 999 | |
duke@435 | 1000 | // If PrintSafepointStatisticsTimeout is specified, the statistics data will |
duke@435 | 1001 | // be printed right away, in which case, _safepoint_stats will regress to |
duke@435 | 1002 | // a single element array. Otherwise, it is a circular ring buffer with default |
duke@435 | 1003 | // size of PrintSafepointStatisticsCount. |
duke@435 | 1004 | int stats_array_size; |
duke@435 | 1005 | if (PrintSafepointStatisticsTimeout > 0) { |
duke@435 | 1006 | stats_array_size = 1; |
duke@435 | 1007 | PrintSafepointStatistics = true; |
duke@435 | 1008 | } else { |
duke@435 | 1009 | stats_array_size = PrintSafepointStatisticsCount; |
duke@435 | 1010 | } |
duke@435 | 1011 | _safepoint_stats = (SafepointStats*)os::malloc(stats_array_size |
duke@435 | 1012 | * sizeof(SafepointStats)); |
duke@435 | 1013 | guarantee(_safepoint_stats != NULL, |
duke@435 | 1014 | "not enough memory for safepoint instrumentation data"); |
duke@435 | 1015 | |
duke@435 | 1016 | if (UseCompilerSafepoints && DeferPollingPageLoopCount >= 0) { |
duke@435 | 1017 | need_to_track_page_armed_status = true; |
duke@435 | 1018 | } |
duke@435 | 1019 | |
duke@435 | 1020 | tty->print(" vmop_name " |
duke@435 | 1021 | "[threads: total initially_running wait_to_block] "); |
duke@435 | 1022 | tty->print("[time: spin block sync] " |
duke@435 | 1023 | "[vmop_time time_elapsed] "); |
duke@435 | 1024 | |
duke@435 | 1025 | // no page armed status printed out if it is always armed. |
duke@435 | 1026 | if (need_to_track_page_armed_status) { |
duke@435 | 1027 | tty->print("page_armed "); |
duke@435 | 1028 | } |
duke@435 | 1029 | |
duke@435 | 1030 | tty->print_cr("page_trap_count"); |
duke@435 | 1031 | |
duke@435 | 1032 | init_done = true; |
duke@435 | 1033 | } |
duke@435 | 1034 | |
duke@435 | 1035 | void SafepointSynchronize::begin_statistics(int nof_threads, int nof_running) { |
xlu@1438 | 1036 | assert(init_done, "safepoint statistics array hasn't been initialized"); |
duke@435 | 1037 | SafepointStats *spstat = &_safepoint_stats[_cur_stat_index]; |
duke@435 | 1038 | |
duke@435 | 1039 | VM_Operation *op = VMThread::vm_operation(); |
duke@435 | 1040 | spstat->_vmop_type = (op != NULL ? op->type() : -1); |
duke@435 | 1041 | if (op != NULL) { |
duke@435 | 1042 | _safepoint_reasons[spstat->_vmop_type]++; |
duke@435 | 1043 | } |
duke@435 | 1044 | |
duke@435 | 1045 | spstat->_nof_total_threads = nof_threads; |
duke@435 | 1046 | spstat->_nof_initial_running_threads = nof_running; |
duke@435 | 1047 | spstat->_nof_threads_hit_page_trap = 0; |
duke@435 | 1048 | |
duke@435 | 1049 | // Records the start time of spinning. The real time spent on spinning |
duke@435 | 1050 | // will be adjusted when spin is done. Same trick is applied for time |
duke@435 | 1051 | // spent on waiting for threads to block. |
duke@435 | 1052 | if (nof_running != 0) { |
duke@435 | 1053 | spstat->_time_to_spin = os::javaTimeNanos(); |
duke@435 | 1054 | } else { |
duke@435 | 1055 | spstat->_time_to_spin = 0; |
duke@435 | 1056 | } |
duke@435 | 1057 | |
duke@435 | 1058 | if (last_safepoint_start_time == 0) { |
duke@435 | 1059 | spstat->_time_elapsed_since_last_safepoint = 0; |
duke@435 | 1060 | } else { |
duke@435 | 1061 | spstat->_time_elapsed_since_last_safepoint = _last_safepoint - |
duke@435 | 1062 | last_safepoint_start_time; |
duke@435 | 1063 | } |
duke@435 | 1064 | last_safepoint_start_time = _last_safepoint; |
duke@435 | 1065 | } |
duke@435 | 1066 | |
duke@435 | 1067 | void SafepointSynchronize::update_statistics_on_spin_end() { |
duke@435 | 1068 | SafepointStats *spstat = &_safepoint_stats[_cur_stat_index]; |
duke@435 | 1069 | |
duke@435 | 1070 | jlong cur_time = os::javaTimeNanos(); |
duke@435 | 1071 | |
duke@435 | 1072 | spstat->_nof_threads_wait_to_block = _waiting_to_block; |
duke@435 | 1073 | if (spstat->_nof_initial_running_threads != 0) { |
duke@435 | 1074 | spstat->_time_to_spin = cur_time - spstat->_time_to_spin; |
duke@435 | 1075 | } |
duke@435 | 1076 | |
duke@435 | 1077 | if (need_to_track_page_armed_status) { |
duke@435 | 1078 | spstat->_page_armed = (PageArmed == 1); |
duke@435 | 1079 | } |
duke@435 | 1080 | |
duke@435 | 1081 | // Records the start time of waiting for to block. Updated when block is done. |
duke@435 | 1082 | if (_waiting_to_block != 0) { |
duke@435 | 1083 | spstat->_time_to_wait_to_block = cur_time; |
duke@435 | 1084 | } else { |
duke@435 | 1085 | spstat->_time_to_wait_to_block = 0; |
duke@435 | 1086 | } |
duke@435 | 1087 | } |
duke@435 | 1088 | |
duke@435 | 1089 | void SafepointSynchronize::update_statistics_on_sync_end(jlong end_time) { |
duke@435 | 1090 | SafepointStats *spstat = &_safepoint_stats[_cur_stat_index]; |
duke@435 | 1091 | |
duke@435 | 1092 | if (spstat->_nof_threads_wait_to_block != 0) { |
duke@435 | 1093 | spstat->_time_to_wait_to_block = end_time - |
duke@435 | 1094 | spstat->_time_to_wait_to_block; |
duke@435 | 1095 | } |
duke@435 | 1096 | |
duke@435 | 1097 | // Records the end time of sync which will be used to calculate the total |
duke@435 | 1098 | // vm operation time. Again, the real time spending in syncing will be deducted |
duke@435 | 1099 | // from the start of the sync time later when end_statistics is called. |
duke@435 | 1100 | spstat->_time_to_sync = end_time - _last_safepoint; |
duke@435 | 1101 | if (spstat->_time_to_sync > _max_sync_time) { |
duke@435 | 1102 | _max_sync_time = spstat->_time_to_sync; |
duke@435 | 1103 | } |
duke@435 | 1104 | sync_end_time = end_time; |
duke@435 | 1105 | } |
duke@435 | 1106 | |
duke@435 | 1107 | void SafepointSynchronize::end_statistics(jlong vmop_end_time) { |
duke@435 | 1108 | SafepointStats *spstat = &_safepoint_stats[_cur_stat_index]; |
duke@435 | 1109 | |
duke@435 | 1110 | // Update the vm operation time. |
duke@435 | 1111 | spstat->_time_to_exec_vmop = vmop_end_time - sync_end_time; |
duke@435 | 1112 | // Only the sync time longer than the specified |
duke@435 | 1113 | // PrintSafepointStatisticsTimeout will be printed out right away. |
duke@435 | 1114 | // By default, it is -1 meaning all samples will be put into the list. |
duke@435 | 1115 | if ( PrintSafepointStatisticsTimeout > 0) { |
duke@435 | 1116 | if (spstat->_time_to_sync > PrintSafepointStatisticsTimeout * MICROUNITS) { |
duke@435 | 1117 | print_statistics(); |
duke@435 | 1118 | } |
duke@435 | 1119 | } else { |
duke@435 | 1120 | // The safepoint statistics will be printed out when the _safepoin_stats |
duke@435 | 1121 | // array fills up. |
duke@435 | 1122 | if (_cur_stat_index != PrintSafepointStatisticsCount - 1) { |
duke@435 | 1123 | _cur_stat_index ++; |
duke@435 | 1124 | } else { |
duke@435 | 1125 | print_statistics(); |
duke@435 | 1126 | _cur_stat_index = 0; |
duke@435 | 1127 | tty->print_cr(""); |
duke@435 | 1128 | } |
duke@435 | 1129 | } |
duke@435 | 1130 | } |
duke@435 | 1131 | |
duke@435 | 1132 | void SafepointSynchronize::print_statistics() { |
duke@435 | 1133 | int index; |
duke@435 | 1134 | SafepointStats* sstats = _safepoint_stats; |
duke@435 | 1135 | |
duke@435 | 1136 | for (index = 0; index <= _cur_stat_index; index++) { |
duke@435 | 1137 | sstats = &_safepoint_stats[index]; |
duke@435 | 1138 | tty->print("%-28s [" |
duke@435 | 1139 | INT32_FORMAT_W(8)INT32_FORMAT_W(11)INT32_FORMAT_W(15) |
duke@435 | 1140 | "] ", |
duke@435 | 1141 | sstats->_vmop_type == -1 ? "no vm operation" : |
duke@435 | 1142 | VM_Operation::name(sstats->_vmop_type), |
duke@435 | 1143 | sstats->_nof_total_threads, |
duke@435 | 1144 | sstats->_nof_initial_running_threads, |
duke@435 | 1145 | sstats->_nof_threads_wait_to_block); |
duke@435 | 1146 | // "/ MICROUNITS " is to convert the unit from nanos to millis. |
duke@435 | 1147 | tty->print(" [" |
duke@435 | 1148 | INT64_FORMAT_W(6)INT64_FORMAT_W(6)INT64_FORMAT_W(6) |
duke@435 | 1149 | "] " |
duke@435 | 1150 | "["INT64_FORMAT_W(6)INT64_FORMAT_W(9) "] ", |
duke@435 | 1151 | sstats->_time_to_spin / MICROUNITS, |
duke@435 | 1152 | sstats->_time_to_wait_to_block / MICROUNITS, |
duke@435 | 1153 | sstats->_time_to_sync / MICROUNITS, |
duke@435 | 1154 | sstats->_time_to_exec_vmop / MICROUNITS, |
duke@435 | 1155 | sstats->_time_elapsed_since_last_safepoint / MICROUNITS); |
duke@435 | 1156 | |
duke@435 | 1157 | if (need_to_track_page_armed_status) { |
duke@435 | 1158 | tty->print(INT32_FORMAT" ", sstats->_page_armed); |
duke@435 | 1159 | } |
duke@435 | 1160 | tty->print_cr(INT32_FORMAT" ", sstats->_nof_threads_hit_page_trap); |
duke@435 | 1161 | } |
duke@435 | 1162 | } |
duke@435 | 1163 | |
duke@435 | 1164 | // This method will be called when VM exits. It will first call |
duke@435 | 1165 | // print_statistics to print out the rest of the sampling. Then |
duke@435 | 1166 | // it tries to summarize the sampling. |
duke@435 | 1167 | void SafepointSynchronize::print_stat_on_exit() { |
duke@435 | 1168 | if (_safepoint_stats == NULL) return; |
duke@435 | 1169 | |
duke@435 | 1170 | SafepointStats *spstat = &_safepoint_stats[_cur_stat_index]; |
duke@435 | 1171 | |
duke@435 | 1172 | // During VM exit, end_statistics may not get called and in that |
duke@435 | 1173 | // case, if the sync time is less than PrintSafepointStatisticsTimeout, |
duke@435 | 1174 | // don't print it out. |
duke@435 | 1175 | // Approximate the vm op time. |
duke@435 | 1176 | _safepoint_stats[_cur_stat_index]._time_to_exec_vmop = |
duke@435 | 1177 | os::javaTimeNanos() - sync_end_time; |
duke@435 | 1178 | |
duke@435 | 1179 | if ( PrintSafepointStatisticsTimeout < 0 || |
duke@435 | 1180 | spstat->_time_to_sync > PrintSafepointStatisticsTimeout * MICROUNITS) { |
duke@435 | 1181 | print_statistics(); |
duke@435 | 1182 | } |
duke@435 | 1183 | tty->print_cr(""); |
duke@435 | 1184 | |
duke@435 | 1185 | // Print out polling page sampling status. |
duke@435 | 1186 | if (!need_to_track_page_armed_status) { |
duke@435 | 1187 | if (UseCompilerSafepoints) { |
duke@435 | 1188 | tty->print_cr("Polling page always armed"); |
duke@435 | 1189 | } |
duke@435 | 1190 | } else { |
duke@435 | 1191 | tty->print_cr("Defer polling page loop count = %d\n", |
duke@435 | 1192 | DeferPollingPageLoopCount); |
duke@435 | 1193 | } |
duke@435 | 1194 | |
duke@435 | 1195 | for (int index = 0; index < VM_Operation::VMOp_Terminating; index++) { |
duke@435 | 1196 | if (_safepoint_reasons[index] != 0) { |
duke@435 | 1197 | tty->print_cr("%-26s"UINT64_FORMAT_W(10), VM_Operation::name(index), |
duke@435 | 1198 | _safepoint_reasons[index]); |
duke@435 | 1199 | } |
duke@435 | 1200 | } |
duke@435 | 1201 | |
duke@435 | 1202 | tty->print_cr(UINT64_FORMAT_W(5)" VM operations coalesced during safepoint", |
duke@435 | 1203 | _coalesced_vmop_count); |
duke@435 | 1204 | tty->print_cr("Maximum sync time "INT64_FORMAT_W(5)" ms", |
duke@435 | 1205 | _max_sync_time / MICROUNITS); |
duke@435 | 1206 | } |
duke@435 | 1207 | |
duke@435 | 1208 | // ------------------------------------------------------------------------------------------------ |
duke@435 | 1209 | // Non-product code |
duke@435 | 1210 | |
duke@435 | 1211 | #ifndef PRODUCT |
duke@435 | 1212 | |
duke@435 | 1213 | void SafepointSynchronize::print_state() { |
duke@435 | 1214 | if (_state == _not_synchronized) { |
duke@435 | 1215 | tty->print_cr("not synchronized"); |
duke@435 | 1216 | } else if (_state == _synchronizing || _state == _synchronized) { |
duke@435 | 1217 | tty->print_cr("State: %s", (_state == _synchronizing) ? "synchronizing" : |
duke@435 | 1218 | "synchronized"); |
duke@435 | 1219 | |
duke@435 | 1220 | for(JavaThread *cur = Threads::first(); cur; cur = cur->next()) { |
duke@435 | 1221 | cur->safepoint_state()->print(); |
duke@435 | 1222 | } |
duke@435 | 1223 | } |
duke@435 | 1224 | } |
duke@435 | 1225 | |
duke@435 | 1226 | void SafepointSynchronize::safepoint_msg(const char* format, ...) { |
duke@435 | 1227 | if (ShowSafepointMsgs) { |
duke@435 | 1228 | va_list ap; |
duke@435 | 1229 | va_start(ap, format); |
duke@435 | 1230 | tty->vprint_cr(format, ap); |
duke@435 | 1231 | va_end(ap); |
duke@435 | 1232 | } |
duke@435 | 1233 | } |
duke@435 | 1234 | |
duke@435 | 1235 | #endif // !PRODUCT |