jdk8-mips64-public/hotspot: src/share/vm/gc_implementation/g1/g1MMUTracker.cpp@15c5903cf9e1 (annotated)

src/share/vm/gc_implementation/g1/g1MMUTracker.cpp@15c5903cf9e1 (annotated)

src/share/vm/gc_implementation/g1/g1MMUTracker.cpp

Mon, 03 Aug 2009 12:59:30 -0700

author: johnc
date: Mon, 03 Aug 2009 12:59:30 -0700
changeset 1324: 15c5903cf9e1
parent 777: 37f87013dfd8
child 1371: e1fdf4fd34dc
permissions: -rw-r--r--

6865703: G1: Parallelize hot card cache cleanup
Summary: Have the GC worker threads clear the hot card cache in parallel by having each worker thread claim a chunk of the card cache and process the cards in that chunk. The size of the chunks that each thread will claim is determined at VM initialization from the size of the card cache and the number of worker threads.
Reviewed-by: jmasa, tonyp

 /*
  * Copyright 2001-2007 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
  * CA 95054 USA or visit www.sun.com if you need additional information or
  * have any questions.
  *
  */
 #include "incls/_precompiled.incl"
 #include "incls/_g1MMUTracker.cpp.incl"
 #define _DISABLE_MMU                             0
 // can't rely on comparing doubles with tolerating a small margin for error
 #define SMALL_MARGIN 0.0000001
 #define is_double_leq_0(_value) ( (_value) < SMALL_MARGIN )
 #define is_double_leq(_val1, _val2) is_double_leq_0((_val1) - (_val2))
 #define is_double_geq(_val1, _val2) is_double_leq_0((_val2) - (_val1))
 /***** ALL TIMES ARE IN SECS!!!!!!! *****/
 G1MMUTracker::G1MMUTracker(double time_slice, double max_gc_time) :
   _time_slice(time_slice),
   _max_gc_time(max_gc_time),
   _conc_overhead_time_sec(0.0) { }
 void
 G1MMUTracker::update_conc_overhead(double conc_overhead) {
   double conc_overhead_time_sec = _time_slice * conc_overhead;
   if (conc_overhead_time_sec > 0.9 * _max_gc_time) {
     // We are screwed, as we only seem to have <10% of the soft
     // real-time goal available for pauses. Let's admit defeat and
     // allow something more generous as a pause target.
     conc_overhead_time_sec = 0.75 * _max_gc_time;
   }
   _conc_overhead_time_sec = conc_overhead_time_sec;
 }
 G1MMUTrackerQueue::G1MMUTrackerQueue(double time_slice, double max_gc_time) :
   G1MMUTracker(time_slice, max_gc_time),
   _head_index(0),
   _tail_index(trim_index(_head_index+1)),
   _no_entries(0) { }
 void G1MMUTrackerQueue::remove_expired_entries(double current_time) {
   double limit = current_time - _time_slice;
   while (_no_entries > 0) {
     if (is_double_geq(limit, _array[_tail_index].end_time())) {
       _tail_index = trim_index(_tail_index + 1);
       --_no_entries;
     } else
       return;
   }
   guarantee(_no_entries == 0, "should have no entries in the array");
 }
 double G1MMUTrackerQueue::calculate_gc_time(double current_time) {
   double gc_time = 0.0;
   double limit = current_time - _time_slice;
   for (int i = 0; i < _no_entries; ++i) {
     int index = trim_index(_tail_index + i);
     G1MMUTrackerQueueElem *elem = &_array[index];
     if (elem->end_time() > limit) {
       if (elem->start_time() > limit)
         gc_time += elem->duration();
       else
         gc_time += elem->end_time() - limit;
     }
   }
   return gc_time;
 }
 void G1MMUTrackerQueue::add_pause(double start, double end, bool gc_thread) {
   double longest_allowed = longest_pause_internal(start);
   if (longest_allowed < 0.0)
     longest_allowed = 0.0;
   double duration = end - start;
   remove_expired_entries(end);
   if (_no_entries == QueueLength) {
     // OK, right now when we fill up we bomb out
     // there are a few ways of dealing with this "gracefully"
     //   increase the array size (:-)
     //   remove the oldest entry (this might allow more GC time for
     //     the time slice than what's allowed)
     //   concolidate the two entries with the minimum gap between them
     //     (this mighte allow less GC time than what's allowed)
     guarantee(0, "array full, currently we can't recover");
   }
   _head_index = trim_index(_head_index + 1);
   ++_no_entries;
   _array[_head_index] = G1MMUTrackerQueueElem(start, end);
 }
 // basically the _internal call does not remove expired entries
 // this is for trying things out in the future and a couple
 // of other places (debugging)
 double G1MMUTrackerQueue::longest_pause(double current_time) {
   if (_DISABLE_MMU)
     return _max_gc_time;
   MutexLockerEx x(MMUTracker_lock, Mutex::_no_safepoint_check_flag);
   remove_expired_entries(current_time);
   return longest_pause_internal(current_time);
 }
 double G1MMUTrackerQueue::longest_pause_internal(double current_time) {
   double target_time = _max_gc_time;
   while( 1 ) {
     double gc_time =
       calculate_gc_time(current_time + target_time) + _conc_overhead_time_sec;
     double diff = target_time + gc_time - _max_gc_time;
     if (!is_double_leq_0(diff)) {
       target_time -= diff;
       if (is_double_leq_0(target_time)) {
         target_time = -1.0;
         break;
       }
     } else {
       break;
     }
   }
   return target_time;
 }
 // basically the _internal call does not remove expired entries
 // this is for trying things out in the future and a couple
 // of other places (debugging)
 double G1MMUTrackerQueue::when_sec(double current_time, double pause_time) {
   if (_DISABLE_MMU)
     return 0.0;
   MutexLockerEx x(MMUTracker_lock, Mutex::_no_safepoint_check_flag);
   remove_expired_entries(current_time);
   return when_internal(current_time, pause_time);
 }
 double G1MMUTrackerQueue::when_internal(double current_time,
                                         double pause_time) {
   // if the pause is over the maximum, just assume that it's the maximum
   double adjusted_pause_time =
     (pause_time > max_gc_time()) ? max_gc_time() : pause_time;
   double earliest_end = current_time + adjusted_pause_time;
   double limit = earliest_end - _time_slice;
   double gc_time = calculate_gc_time(earliest_end);
   double diff = gc_time + adjusted_pause_time - max_gc_time();
   if (is_double_leq_0(diff))
     return 0.0;
   int index = _tail_index;
   while ( 1 ) {
     G1MMUTrackerQueueElem *elem = &_array[index];
     if (elem->end_time() > limit) {
       if (elem->start_time() > limit)
         diff -= elem->duration();
       else
         diff -= elem->end_time() - limit;
       if (is_double_leq_0(diff))
         return  elem->end_time() + diff + _time_slice - adjusted_pause_time - current_time;
     }
     index = trim_index(index+1);
     guarantee(index != trim_index(_head_index + 1), "should not go past head");
   }
 }

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/gc_implementation/g1/g1MMUTracker.cpp@15c5903cf9e1 (annotated)

src/share/vm/gc_implementation/g1/g1MMUTracker.cpp