jdk8-mips64-public/hotspot: src/share/vm/utilities/taskqueue.cpp@c18cbe5936b8 (annotated)

src/share/vm/utilities/taskqueue.cpp@c18cbe5936b8 (annotated)

src/share/vm/utilities/taskqueue.cpp

Thu, 27 May 2010 19:08:38 -0700

author: trims
date: Thu, 27 May 2010 19:08:38 -0700
changeset 1907: c18cbe5936b8
parent 1746: 2a1472c30599
child 1993: b2a00dd3117c
permissions: -rw-r--r--

6941466: Oracle rebranding changes for Hotspot repositories
Summary: Change all the Sun copyrights to Oracle copyright
Reviewed-by: ohair

 /*
  * Copyright (c) 2001, 2009, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.
  *
  * This code is distributed in the hope that it will be useful, but WITHOUT
  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  * version 2 for more details (a copy is included in the LICENSE file that
  * accompanied this code).
  *
  * You should have received a copy of the GNU General Public License version
  * 2 along with this work; if not, write to the Free Software Foundation,
  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  *
  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  * or visit www.oracle.com if you need additional information or have any
  * questions.
  *
  */
 # include "incls/_precompiled.incl"
 # include "incls/_taskqueue.cpp.incl"
 #ifdef TRACESPINNING
 uint ParallelTaskTerminator::_total_yields = 0;
 uint ParallelTaskTerminator::_total_spins = 0;
 uint ParallelTaskTerminator::_total_peeks = 0;
 #endif
 int TaskQueueSetSuper::randomParkAndMiller(int *seed0) {
   const int a =      16807;
   const int m = 2147483647;
   const int q =     127773;  /* m div a */
   const int r =       2836;  /* m mod a */
   assert(sizeof(int) == 4, "I think this relies on that");
   int seed = *seed0;
   int hi   = seed / q;
   int lo   = seed % q;
   int test = a * lo - r * hi;
   if (test > 0)
     seed = test;
   else
     seed = test + m;
   *seed0 = seed;
   return seed;
 }
 ParallelTaskTerminator::
 ParallelTaskTerminator(int n_threads, TaskQueueSetSuper* queue_set) :
   _n_threads(n_threads),
   _queue_set(queue_set),
   _offered_termination(0) {}
 bool ParallelTaskTerminator::peek_in_queue_set() {
   return _queue_set->peek();
 }
 void ParallelTaskTerminator::yield() {
   assert(_offered_termination <= _n_threads, "Invariant");
   os::yield();
 }
 void ParallelTaskTerminator::sleep(uint millis) {
   assert(_offered_termination <= _n_threads, "Invariant");
   os::sleep(Thread::current(), millis, false);
 }
 bool
 ParallelTaskTerminator::offer_termination(TerminatorTerminator* terminator) {
   assert(_offered_termination < _n_threads, "Invariant");
   Atomic::inc(&_offered_termination);
   uint yield_count = 0;
   // Number of hard spin loops done since last yield
   uint hard_spin_count = 0;
   // Number of iterations in the hard spin loop.
   uint hard_spin_limit = WorkStealingHardSpins;
   // If WorkStealingSpinToYieldRatio is 0, no hard spinning is done.
   // If it is greater than 0, then start with a small number
   // of spins and increase number with each turn at spinning until
   // the count of hard spins exceeds WorkStealingSpinToYieldRatio.
   // Then do a yield() call and start spinning afresh.
   if (WorkStealingSpinToYieldRatio > 0) {
     hard_spin_limit = WorkStealingHardSpins >> WorkStealingSpinToYieldRatio;
     hard_spin_limit = MAX2(hard_spin_limit, 1U);
   }
   // Remember the initial spin limit.
   uint hard_spin_start = hard_spin_limit;
   // Loop waiting for all threads to offer termination or
   // more work.
   while (true) {
     assert(_offered_termination <= _n_threads, "Invariant");
     // Are all threads offering termination?
     if (_offered_termination == _n_threads) {
       return true;
     } else {
       // Look for more work.
       // Periodically sleep() instead of yield() to give threads
       // waiting on the cores the chance to grab this code
       if (yield_count <= WorkStealingYieldsBeforeSleep) {
         // Do a yield or hardspin.  For purposes of deciding whether
         // to sleep, count this as a yield.
         yield_count++;
         // Periodically call yield() instead spinning
         // After WorkStealingSpinToYieldRatio spins, do a yield() call
         // and reset the counts and starting limit.
         if (hard_spin_count > WorkStealingSpinToYieldRatio) {
           yield();
           hard_spin_count = 0;
           hard_spin_limit = hard_spin_start;
 #ifdef TRACESPINNING
           _total_yields++;
 #endif
         } else {
           // Hard spin this time
           // Increase the hard spinning period but only up to a limit.
           hard_spin_limit = MIN2(2*hard_spin_limit,
                                  (uint) WorkStealingHardSpins);
           for (uint j = 0; j < hard_spin_limit; j++) {
             SpinPause();
           }
           hard_spin_count++;
 #ifdef TRACESPINNING
           _total_spins++;
 #endif
         }
       } else {
         if (PrintGCDetails && Verbose) {
          gclog_or_tty->print_cr("ParallelTaskTerminator::offer_termination() "
            "thread %d sleeps after %d yields",
            Thread::current(), yield_count);
         }
         yield_count = 0;
         // A sleep will cause this processor to seek work on another processor's
         // runqueue, if it has nothing else to run (as opposed to the yield
         // which may only move the thread to the end of the this processor's
         // runqueue).
         sleep(WorkStealingSleepMillis);
       }
 #ifdef TRACESPINNING
       _total_peeks++;
 #endif
       if (peek_in_queue_set() ||
           (terminator != NULL && terminator->should_exit_termination())) {
         Atomic::dec(&_offered_termination);
         assert(_offered_termination < _n_threads, "Invariant");
         return false;
       }
     }
   }
 }
 #ifdef TRACESPINNING
 void ParallelTaskTerminator::print_termination_counts() {
   gclog_or_tty->print_cr("ParallelTaskTerminator Total yields: %lld  "
     "Total spins: %lld  Total peeks: %lld",
     total_yields(),
     total_spins(),
     total_peeks());
 }
 #endif
 void ParallelTaskTerminator::reset_for_reuse() {
   if (_offered_termination != 0) {
     assert(_offered_termination == _n_threads,
            "Terminator may still be in use");
     _offered_termination = 0;
   }
 }
 #ifdef ASSERT
 bool ObjArrayTask::is_valid() const {
   return _obj != NULL && _obj->is_objArray() && _index > 0 &&
     _index < objArrayOop(_obj)->length();
 }
 #endif // ASSERT
 bool RegionTaskQueueWithOverflow::is_empty() {
   return (_region_queue.size() == 0) &&
          (_overflow_stack->length() == 0);
 }
 bool RegionTaskQueueWithOverflow::stealable_is_empty() {
   return _region_queue.size() == 0;
 }
 bool RegionTaskQueueWithOverflow::overflow_is_empty() {
   return _overflow_stack->length() == 0;
 }
 void RegionTaskQueueWithOverflow::initialize() {
   _region_queue.initialize();
   assert(_overflow_stack == 0, "Creating memory leak");
   _overflow_stack =
     new (ResourceObj::C_HEAP) GrowableArray<RegionTask>(10, true);
 }
 void RegionTaskQueueWithOverflow::save(RegionTask t) {
   if (TraceRegionTasksQueuing && Verbose) {
     gclog_or_tty->print_cr("CTQ: save " PTR_FORMAT, t);
   }
   if(!_region_queue.push(t)) {
     _overflow_stack->push(t);
   }
 }
 // Note that using this method will retrieve all regions
 // that have been saved but that it will always check
 // the overflow stack.  It may be more efficient to
 // check the stealable queue and the overflow stack
 // separately.
 bool RegionTaskQueueWithOverflow::retrieve(RegionTask& region_task) {
   bool result = retrieve_from_overflow(region_task);
   if (!result) {
     result = retrieve_from_stealable_queue(region_task);
   }
   if (TraceRegionTasksQueuing && Verbose && result) {
     gclog_or_tty->print_cr("  CTQ: retrieve " PTR_FORMAT, result);
   }
   return result;
 }
 bool RegionTaskQueueWithOverflow::retrieve_from_stealable_queue(
                                    RegionTask& region_task) {
   bool result = _region_queue.pop_local(region_task);
   if (TraceRegionTasksQueuing && Verbose) {
     gclog_or_tty->print_cr("CTQ: retrieve_stealable " PTR_FORMAT, region_task);
   }
   return result;
 }
 bool
 RegionTaskQueueWithOverflow::retrieve_from_overflow(RegionTask& region_task) {
   bool result;
   if (!_overflow_stack->is_empty()) {
     region_task = _overflow_stack->pop();
     result = true;
   } else {
     region_task = (RegionTask) NULL;
     result = false;
   }
   if (TraceRegionTasksQueuing && Verbose) {
     gclog_or_tty->print_cr("CTQ: retrieve_stealable " PTR_FORMAT, region_task);
   }
   return result;
 }

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/utilities/taskqueue.cpp@c18cbe5936b8 (annotated)

src/share/vm/utilities/taskqueue.cpp