1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/src/share/vm/utilities/workgroup.cpp Sat Dec 01 00:00:00 2007 +0000
1.3 @@ -0,0 +1,444 @@
1.4 +/*
1.5 + * Copyright 2001-2007 Sun Microsystems, Inc. All Rights Reserved.
1.6 + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
1.7 + *
1.8 + * This code is free software; you can redistribute it and/or modify it
1.9 + * under the terms of the GNU General Public License version 2 only, as
1.10 + * published by the Free Software Foundation.
1.11 + *
1.12 + * This code is distributed in the hope that it will be useful, but WITHOUT
1.13 + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
1.14 + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
1.15 + * version 2 for more details (a copy is included in the LICENSE file that
1.16 + * accompanied this code).
1.17 + *
1.18 + * You should have received a copy of the GNU General Public License version
1.19 + * 2 along with this work; if not, write to the Free Software Foundation,
1.20 + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
1.21 + *
1.22 + * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
1.23 + * CA 95054 USA or visit www.sun.com if you need additional information or
1.24 + * have any questions.
1.25 + *
1.26 + */
1.27 +
1.28 +# include "incls/_precompiled.incl"
1.29 +# include "incls/_workgroup.cpp.incl"
1.30 +
1.31 +// Definitions of WorkGang methods.
1.32 +
1.33 +AbstractWorkGang::AbstractWorkGang(const char* name,
1.34 + bool are_GC_threads) :
1.35 + _name(name),
1.36 + _are_GC_threads(are_GC_threads) {
1.37 + // Other initialization.
1.38 + _monitor = new Monitor(/* priority */ Mutex::leaf,
1.39 + /* name */ "WorkGroup monitor",
1.40 + /* allow_vm_block */ are_GC_threads);
1.41 + assert(monitor() != NULL, "Failed to allocate monitor");
1.42 + _terminate = false;
1.43 + _task = NULL;
1.44 + _sequence_number = 0;
1.45 + _started_workers = 0;
1.46 + _finished_workers = 0;
1.47 +}
1.48 +
1.49 +WorkGang::WorkGang(const char* name,
1.50 + int workers,
1.51 + bool are_GC_threads) :
1.52 + AbstractWorkGang(name, are_GC_threads) {
1.53 + // Save arguments.
1.54 + _total_workers = workers;
1.55 + if (TraceWorkGang) {
1.56 + tty->print_cr("Constructing work gang %s with %d threads", name, workers);
1.57 + }
1.58 + _gang_workers = NEW_C_HEAP_ARRAY(GangWorker*, workers);
1.59 + assert(gang_workers() != NULL, "Failed to allocate gang workers");
1.60 + for (int worker = 0; worker < total_workers(); worker += 1) {
1.61 + GangWorker* new_worker = new GangWorker(this, worker);
1.62 + assert(new_worker != NULL, "Failed to allocate GangWorker");
1.63 + _gang_workers[worker] = new_worker;
1.64 + if (new_worker == NULL || !os::create_thread(new_worker, os::pgc_thread))
1.65 + vm_exit_out_of_memory(0, "Cannot create worker GC thread. Out of system resources.");
1.66 + if (!DisableStartThread) {
1.67 + os::start_thread(new_worker);
1.68 + }
1.69 + }
1.70 +}
1.71 +
1.72 +AbstractWorkGang::~AbstractWorkGang() {
1.73 + if (TraceWorkGang) {
1.74 + tty->print_cr("Destructing work gang %s", name());
1.75 + }
1.76 + stop(); // stop all the workers
1.77 + for (int worker = 0; worker < total_workers(); worker += 1) {
1.78 + delete gang_worker(worker);
1.79 + }
1.80 + delete gang_workers();
1.81 + delete monitor();
1.82 +}
1.83 +
1.84 +GangWorker* AbstractWorkGang::gang_worker(int i) const {
1.85 + // Array index bounds checking.
1.86 + GangWorker* result = NULL;
1.87 + assert(gang_workers() != NULL, "No workers for indexing");
1.88 + assert(((i >= 0) && (i < total_workers())), "Worker index out of bounds");
1.89 + result = _gang_workers[i];
1.90 + assert(result != NULL, "Indexing to null worker");
1.91 + return result;
1.92 +}
1.93 +
1.94 +void WorkGang::run_task(AbstractGangTask* task) {
1.95 + // This thread is executed by the VM thread which does not block
1.96 + // on ordinary MutexLocker's.
1.97 + MutexLockerEx ml(monitor(), Mutex::_no_safepoint_check_flag);
1.98 + if (TraceWorkGang) {
1.99 + tty->print_cr("Running work gang %s task %s", name(), task->name());
1.100 + }
1.101 + // Tell all the workers to run a task.
1.102 + assert(task != NULL, "Running a null task");
1.103 + // Initialize.
1.104 + _task = task;
1.105 + _sequence_number += 1;
1.106 + _started_workers = 0;
1.107 + _finished_workers = 0;
1.108 + // Tell the workers to get to work.
1.109 + monitor()->notify_all();
1.110 + // Wait for them to be finished
1.111 + while (finished_workers() < total_workers()) {
1.112 + if (TraceWorkGang) {
1.113 + tty->print_cr("Waiting in work gang %s: %d/%d finished sequence %d",
1.114 + name(), finished_workers(), total_workers(),
1.115 + _sequence_number);
1.116 + }
1.117 + monitor()->wait(/* no_safepoint_check */ true);
1.118 + }
1.119 + _task = NULL;
1.120 + if (TraceWorkGang) {
1.121 + tty->print_cr("/nFinished work gang %s: %d/%d sequence %d",
1.122 + name(), finished_workers(), total_workers(),
1.123 + _sequence_number);
1.124 + }
1.125 +}
1.126 +
1.127 +void AbstractWorkGang::stop() {
1.128 + // Tell all workers to terminate, then wait for them to become inactive.
1.129 + MutexLockerEx ml(monitor(), Mutex::_no_safepoint_check_flag);
1.130 + if (TraceWorkGang) {
1.131 + tty->print_cr("Stopping work gang %s task %s", name(), task()->name());
1.132 + }
1.133 + _task = NULL;
1.134 + _terminate = true;
1.135 + monitor()->notify_all();
1.136 + while (finished_workers() < total_workers()) {
1.137 + if (TraceWorkGang) {
1.138 + tty->print_cr("Waiting in work gang %s: %d/%d finished",
1.139 + name(), finished_workers(), total_workers());
1.140 + }
1.141 + monitor()->wait(/* no_safepoint_check */ true);
1.142 + }
1.143 +}
1.144 +
1.145 +void AbstractWorkGang::internal_worker_poll(WorkData* data) const {
1.146 + assert(monitor()->owned_by_self(), "worker_poll is an internal method");
1.147 + assert(data != NULL, "worker data is null");
1.148 + data->set_terminate(terminate());
1.149 + data->set_task(task());
1.150 + data->set_sequence_number(sequence_number());
1.151 +}
1.152 +
1.153 +void AbstractWorkGang::internal_note_start() {
1.154 + assert(monitor()->owned_by_self(), "note_finish is an internal method");
1.155 + _started_workers += 1;
1.156 +}
1.157 +
1.158 +void AbstractWorkGang::internal_note_finish() {
1.159 + assert(monitor()->owned_by_self(), "note_finish is an internal method");
1.160 + _finished_workers += 1;
1.161 +}
1.162 +
1.163 +void AbstractWorkGang::print_worker_threads_on(outputStream* st) const {
1.164 + uint num_thr = total_workers();
1.165 + for (uint i = 0; i < num_thr; i++) {
1.166 + gang_worker(i)->print_on(st);
1.167 + st->cr();
1.168 + }
1.169 +}
1.170 +
1.171 +void AbstractWorkGang::threads_do(ThreadClosure* tc) const {
1.172 + assert(tc != NULL, "Null ThreadClosure");
1.173 + uint num_thr = total_workers();
1.174 + for (uint i = 0; i < num_thr; i++) {
1.175 + tc->do_thread(gang_worker(i));
1.176 + }
1.177 +}
1.178 +
1.179 +// GangWorker methods.
1.180 +
1.181 +GangWorker::GangWorker(AbstractWorkGang* gang, uint id) {
1.182 + _gang = gang;
1.183 + set_id(id);
1.184 + set_name("Gang worker#%d (%s)", id, gang->name());
1.185 +}
1.186 +
1.187 +void GangWorker::run() {
1.188 + initialize();
1.189 + loop();
1.190 +}
1.191 +
1.192 +void GangWorker::initialize() {
1.193 + this->initialize_thread_local_storage();
1.194 + assert(_gang != NULL, "No gang to run in");
1.195 + os::set_priority(this, NearMaxPriority);
1.196 + if (TraceWorkGang) {
1.197 + tty->print_cr("Running gang worker for gang %s id %d",
1.198 + gang()->name(), id());
1.199 + }
1.200 + // The VM thread should not execute here because MutexLocker's are used
1.201 + // as (opposed to MutexLockerEx's).
1.202 + assert(!Thread::current()->is_VM_thread(), "VM thread should not be part"
1.203 + " of a work gang");
1.204 +}
1.205 +
1.206 +void GangWorker::loop() {
1.207 + int previous_sequence_number = 0;
1.208 + Monitor* gang_monitor = gang()->monitor();
1.209 + for ( ; /* !terminate() */; ) {
1.210 + WorkData data;
1.211 + int part; // Initialized below.
1.212 + {
1.213 + // Grab the gang mutex.
1.214 + MutexLocker ml(gang_monitor);
1.215 + // Wait for something to do.
1.216 + // Polling outside the while { wait } avoids missed notifies
1.217 + // in the outer loop.
1.218 + gang()->internal_worker_poll(&data);
1.219 + if (TraceWorkGang) {
1.220 + tty->print("Polled outside for work in gang %s worker %d",
1.221 + gang()->name(), id());
1.222 + tty->print(" terminate: %s",
1.223 + data.terminate() ? "true" : "false");
1.224 + tty->print(" sequence: %d (prev: %d)",
1.225 + data.sequence_number(), previous_sequence_number);
1.226 + if (data.task() != NULL) {
1.227 + tty->print(" task: %s", data.task()->name());
1.228 + } else {
1.229 + tty->print(" task: NULL");
1.230 + }
1.231 + tty->cr();
1.232 + }
1.233 + for ( ; /* break or return */; ) {
1.234 + // Terminate if requested.
1.235 + if (data.terminate()) {
1.236 + gang()->internal_note_finish();
1.237 + gang_monitor->notify_all();
1.238 + return;
1.239 + }
1.240 + // Check for new work.
1.241 + if ((data.task() != NULL) &&
1.242 + (data.sequence_number() != previous_sequence_number)) {
1.243 + gang()->internal_note_start();
1.244 + gang_monitor->notify_all();
1.245 + part = gang()->started_workers() - 1;
1.246 + break;
1.247 + }
1.248 + // Nothing to do.
1.249 + gang_monitor->wait(/* no_safepoint_check */ true);
1.250 + gang()->internal_worker_poll(&data);
1.251 + if (TraceWorkGang) {
1.252 + tty->print("Polled inside for work in gang %s worker %d",
1.253 + gang()->name(), id());
1.254 + tty->print(" terminate: %s",
1.255 + data.terminate() ? "true" : "false");
1.256 + tty->print(" sequence: %d (prev: %d)",
1.257 + data.sequence_number(), previous_sequence_number);
1.258 + if (data.task() != NULL) {
1.259 + tty->print(" task: %s", data.task()->name());
1.260 + } else {
1.261 + tty->print(" task: NULL");
1.262 + }
1.263 + tty->cr();
1.264 + }
1.265 + }
1.266 + // Drop gang mutex.
1.267 + }
1.268 + if (TraceWorkGang) {
1.269 + tty->print("Work for work gang %s id %d task %s part %d",
1.270 + gang()->name(), id(), data.task()->name(), part);
1.271 + }
1.272 + assert(data.task() != NULL, "Got null task");
1.273 + data.task()->work(part);
1.274 + {
1.275 + if (TraceWorkGang) {
1.276 + tty->print("Finish for work gang %s id %d task %s part %d",
1.277 + gang()->name(), id(), data.task()->name(), part);
1.278 + }
1.279 + // Grab the gang mutex.
1.280 + MutexLocker ml(gang_monitor);
1.281 + gang()->internal_note_finish();
1.282 + // Tell the gang you are done.
1.283 + gang_monitor->notify_all();
1.284 + // Drop the gang mutex.
1.285 + }
1.286 + previous_sequence_number = data.sequence_number();
1.287 + }
1.288 +}
1.289 +
1.290 +bool GangWorker::is_GC_task_thread() const {
1.291 + return gang()->are_GC_threads();
1.292 +}
1.293 +
1.294 +void GangWorker::print_on(outputStream* st) const {
1.295 + st->print("\"%s\" ", name());
1.296 + Thread::print_on(st);
1.297 + st->cr();
1.298 +}
1.299 +
1.300 +// Printing methods
1.301 +
1.302 +const char* AbstractWorkGang::name() const {
1.303 + return _name;
1.304 +}
1.305 +
1.306 +#ifndef PRODUCT
1.307 +
1.308 +const char* AbstractGangTask::name() const {
1.309 + return _name;
1.310 +}
1.311 +
1.312 +#endif /* PRODUCT */
1.313 +
1.314 +// *** WorkGangBarrierSync
1.315 +
1.316 +WorkGangBarrierSync::WorkGangBarrierSync()
1.317 + : _monitor(Mutex::safepoint, "work gang barrier sync", true),
1.318 + _n_workers(0), _n_completed(0) {
1.319 +}
1.320 +
1.321 +WorkGangBarrierSync::WorkGangBarrierSync(int n_workers, const char* name)
1.322 + : _monitor(Mutex::safepoint, name, true),
1.323 + _n_workers(n_workers), _n_completed(0) {
1.324 +}
1.325 +
1.326 +void WorkGangBarrierSync::set_n_workers(int n_workers) {
1.327 + _n_workers = n_workers;
1.328 + _n_completed = 0;
1.329 +}
1.330 +
1.331 +void WorkGangBarrierSync::enter() {
1.332 + MutexLockerEx x(monitor(), Mutex::_no_safepoint_check_flag);
1.333 + inc_completed();
1.334 + if (n_completed() == n_workers()) {
1.335 + monitor()->notify_all();
1.336 + }
1.337 + else {
1.338 + while (n_completed() != n_workers()) {
1.339 + monitor()->wait(/* no_safepoint_check */ true);
1.340 + }
1.341 + }
1.342 +}
1.343 +
1.344 +// SubTasksDone functions.
1.345 +
1.346 +SubTasksDone::SubTasksDone(int n) :
1.347 + _n_tasks(n), _n_threads(1), _tasks(NULL) {
1.348 + _tasks = NEW_C_HEAP_ARRAY(jint, n);
1.349 + guarantee(_tasks != NULL, "alloc failure");
1.350 + clear();
1.351 +}
1.352 +
1.353 +bool SubTasksDone::valid() {
1.354 + return _tasks != NULL;
1.355 +}
1.356 +
1.357 +void SubTasksDone::set_par_threads(int t) {
1.358 +#ifdef ASSERT
1.359 + assert(_claimed == 0 || _threads_completed == _n_threads,
1.360 + "should not be called while tasks are being processed!");
1.361 +#endif
1.362 + _n_threads = (t == 0 ? 1 : t);
1.363 +}
1.364 +
1.365 +void SubTasksDone::clear() {
1.366 + for (int i = 0; i < _n_tasks; i++) {
1.367 + _tasks[i] = 0;
1.368 + }
1.369 + _threads_completed = 0;
1.370 +#ifdef ASSERT
1.371 + _claimed = 0;
1.372 +#endif
1.373 +}
1.374 +
1.375 +bool SubTasksDone::is_task_claimed(int t) {
1.376 + assert(0 <= t && t < _n_tasks, "bad task id.");
1.377 + jint old = _tasks[t];
1.378 + if (old == 0) {
1.379 + old = Atomic::cmpxchg(1, &_tasks[t], 0);
1.380 + }
1.381 + assert(_tasks[t] == 1, "What else?");
1.382 + bool res = old != 0;
1.383 +#ifdef ASSERT
1.384 + if (!res) {
1.385 + assert(_claimed < _n_tasks, "Too many tasks claimed; missing clear?");
1.386 + Atomic::inc(&_claimed);
1.387 + }
1.388 +#endif
1.389 + return res;
1.390 +}
1.391 +
1.392 +void SubTasksDone::all_tasks_completed() {
1.393 + jint observed = _threads_completed;
1.394 + jint old;
1.395 + do {
1.396 + old = observed;
1.397 + observed = Atomic::cmpxchg(old+1, &_threads_completed, old);
1.398 + } while (observed != old);
1.399 + // If this was the last thread checking in, clear the tasks.
1.400 + if (observed+1 == _n_threads) clear();
1.401 +}
1.402 +
1.403 +
1.404 +SubTasksDone::~SubTasksDone() {
1.405 + if (_tasks != NULL) FREE_C_HEAP_ARRAY(jint, _tasks);
1.406 +}
1.407 +
1.408 +// *** SequentialSubTasksDone
1.409 +
1.410 +void SequentialSubTasksDone::clear() {
1.411 + _n_tasks = _n_claimed = 0;
1.412 + _n_threads = _n_completed = 0;
1.413 +}
1.414 +
1.415 +bool SequentialSubTasksDone::valid() {
1.416 + return _n_threads > 0;
1.417 +}
1.418 +
1.419 +bool SequentialSubTasksDone::is_task_claimed(int& t) {
1.420 + jint* n_claimed_ptr = &_n_claimed;
1.421 + t = *n_claimed_ptr;
1.422 + while (t < _n_tasks) {
1.423 + jint res = Atomic::cmpxchg(t+1, n_claimed_ptr, t);
1.424 + if (res == t) {
1.425 + return false;
1.426 + }
1.427 + t = *n_claimed_ptr;
1.428 + }
1.429 + return true;
1.430 +}
1.431 +
1.432 +bool SequentialSubTasksDone::all_tasks_completed() {
1.433 + jint* n_completed_ptr = &_n_completed;
1.434 + jint complete = *n_completed_ptr;
1.435 + while (true) {
1.436 + jint res = Atomic::cmpxchg(complete+1, n_completed_ptr, complete);
1.437 + if (res == complete) {
1.438 + break;
1.439 + }
1.440 + complete = res;
1.441 + }
1.442 + if (complete+1 == _n_threads) {
1.443 + clear();
1.444 + return true;
1.445 + }
1.446 + return false;
1.447 +}
