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

Tue, 28 May 2013 09:32:06 +0200

author
tschatzl
date
Tue, 28 May 2013 09:32:06 +0200
changeset 5204
e72f7eecc96d
parent 3114
20213c8a3c40
child 6876
710a3c8b516e
child 9858
b985cbb00e68
permissions
-rw-r--r--

8013895: G1: G1SummarizeRSetStats output on Linux needs improvemen
Summary: Fixed the output of G1SummarizeRSetStats: too small datatype for the number of concurrently processed cards, added concurrent remembered set thread time retrieval for Linux and Windows (BSD uses os::elapsedTime() now), and other cleanup. The information presented during VM operation is now relative to the previous output, not always cumulative if G1SummarizeRSetStatsPeriod > 0. At VM exit, the code prints a cumulative summary.
Reviewed-by: johnc, jwilhelm

ysr@777 1 /*
tonyp@3114 2 * Copyright (c) 2001, 2011, Oracle and/or its affiliates. All rights reserved.
ysr@777 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
ysr@777 4 *
ysr@777 5 * This code is free software; you can redistribute it and/or modify it
ysr@777 6 * under the terms of the GNU General Public License version 2 only, as
ysr@777 7 * published by the Free Software Foundation.
ysr@777 8 *
ysr@777 9 * This code is distributed in the hope that it will be useful, but WITHOUT
ysr@777 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
ysr@777 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
ysr@777 12 * version 2 for more details (a copy is included in the LICENSE file that
ysr@777 13 * accompanied this code).
ysr@777 14 *
ysr@777 15 * You should have received a copy of the GNU General Public License version
ysr@777 16 * 2 along with this work; if not, write to the Free Software Foundation,
ysr@777 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
ysr@777 18 *
trims@1907 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
trims@1907 20 * or visit www.oracle.com if you need additional information or have any
trims@1907 21 * questions.
ysr@777 22 *
ysr@777 23 */
ysr@777 24
stefank@2314 25 #include "precompiled.hpp"
stefank@2314 26 #include "gc_implementation/g1/g1MMUTracker.hpp"
stefank@2314 27 #include "runtime/mutexLocker.hpp"
stefank@2314 28 #include "utilities/ostream.hpp"
ysr@777 29
ysr@777 30 #define _DISABLE_MMU 0
ysr@777 31
ysr@777 32 // can't rely on comparing doubles with tolerating a small margin for error
ysr@777 33 #define SMALL_MARGIN 0.0000001
ysr@777 34 #define is_double_leq_0(_value) ( (_value) < SMALL_MARGIN )
ysr@777 35 #define is_double_leq(_val1, _val2) is_double_leq_0((_val1) - (_val2))
ysr@777 36 #define is_double_geq(_val1, _val2) is_double_leq_0((_val2) - (_val1))
ysr@777 37
ysr@777 38 /***** ALL TIMES ARE IN SECS!!!!!!! *****/
ysr@777 39
ysr@777 40 G1MMUTracker::G1MMUTracker(double time_slice, double max_gc_time) :
ysr@777 41 _time_slice(time_slice),
tonyp@1371 42 _max_gc_time(max_gc_time) { }
ysr@777 43
ysr@777 44 G1MMUTrackerQueue::G1MMUTrackerQueue(double time_slice, double max_gc_time) :
ysr@777 45 G1MMUTracker(time_slice, max_gc_time),
ysr@777 46 _head_index(0),
ysr@777 47 _tail_index(trim_index(_head_index+1)),
ysr@777 48 _no_entries(0) { }
ysr@777 49
ysr@777 50 void G1MMUTrackerQueue::remove_expired_entries(double current_time) {
ysr@777 51 double limit = current_time - _time_slice;
ysr@777 52 while (_no_entries > 0) {
ysr@777 53 if (is_double_geq(limit, _array[_tail_index].end_time())) {
ysr@777 54 _tail_index = trim_index(_tail_index + 1);
ysr@777 55 --_no_entries;
ysr@777 56 } else
ysr@777 57 return;
ysr@777 58 }
ysr@777 59 guarantee(_no_entries == 0, "should have no entries in the array");
ysr@777 60 }
ysr@777 61
ysr@777 62 double G1MMUTrackerQueue::calculate_gc_time(double current_time) {
ysr@777 63 double gc_time = 0.0;
ysr@777 64 double limit = current_time - _time_slice;
ysr@777 65 for (int i = 0; i < _no_entries; ++i) {
ysr@777 66 int index = trim_index(_tail_index + i);
ysr@777 67 G1MMUTrackerQueueElem *elem = &_array[index];
ysr@777 68 if (elem->end_time() > limit) {
ysr@777 69 if (elem->start_time() > limit)
ysr@777 70 gc_time += elem->duration();
ysr@777 71 else
ysr@777 72 gc_time += elem->end_time() - limit;
ysr@777 73 }
ysr@777 74 }
ysr@777 75 return gc_time;
ysr@777 76 }
ysr@777 77
ysr@777 78 void G1MMUTrackerQueue::add_pause(double start, double end, bool gc_thread) {
ysr@777 79 double longest_allowed = longest_pause_internal(start);
ysr@777 80 if (longest_allowed < 0.0)
ysr@777 81 longest_allowed = 0.0;
ysr@777 82 double duration = end - start;
ysr@777 83
ysr@777 84 remove_expired_entries(end);
ysr@777 85 if (_no_entries == QueueLength) {
johnc@1946 86 // OK, we've filled up the queue. There are a few ways
johnc@1946 87 // of dealing with this "gracefully"
ysr@777 88 // increase the array size (:-)
ysr@777 89 // remove the oldest entry (this might allow more GC time for
johnc@1946 90 // the time slice than what's allowed) - this is what we
johnc@1946 91 // currently do
ysr@1523 92 // consolidate the two entries with the minimum gap between them
ysr@1523 93 // (this might allow less GC time than what's allowed)
johnc@1946 94
ysr@1523 95 // In the case where ScavengeALot is true, such overflow is not
ysr@1523 96 // uncommon; in such cases, we can, without much loss of precision
ysr@1523 97 // or performance (we are GC'ing most of the time anyway!),
johnc@1946 98 // simply overwrite the oldest entry in the tracker.
johnc@1946 99
ysr@1523 100 _head_index = trim_index(_head_index + 1);
ysr@1523 101 assert(_head_index == _tail_index, "Because we have a full circular buffer");
ysr@1523 102 _tail_index = trim_index(_tail_index + 1);
ysr@1523 103 } else {
ysr@1523 104 _head_index = trim_index(_head_index + 1);
ysr@1523 105 ++_no_entries;
ysr@777 106 }
ysr@777 107 _array[_head_index] = G1MMUTrackerQueueElem(start, end);
ysr@777 108 }
ysr@777 109
ysr@777 110 // basically the _internal call does not remove expired entries
ysr@777 111 // this is for trying things out in the future and a couple
ysr@777 112 // of other places (debugging)
ysr@777 113
ysr@777 114 double G1MMUTrackerQueue::longest_pause(double current_time) {
ysr@777 115 if (_DISABLE_MMU)
ysr@777 116 return _max_gc_time;
ysr@777 117
ysr@777 118 MutexLockerEx x(MMUTracker_lock, Mutex::_no_safepoint_check_flag);
ysr@777 119 remove_expired_entries(current_time);
ysr@777 120
ysr@777 121 return longest_pause_internal(current_time);
ysr@777 122 }
ysr@777 123
ysr@777 124 double G1MMUTrackerQueue::longest_pause_internal(double current_time) {
ysr@777 125 double target_time = _max_gc_time;
ysr@777 126
ysr@777 127 while( 1 ) {
ysr@777 128 double gc_time =
tonyp@1371 129 calculate_gc_time(current_time + target_time);
ysr@777 130 double diff = target_time + gc_time - _max_gc_time;
ysr@777 131 if (!is_double_leq_0(diff)) {
ysr@777 132 target_time -= diff;
ysr@777 133 if (is_double_leq_0(target_time)) {
ysr@777 134 target_time = -1.0;
ysr@777 135 break;
ysr@777 136 }
ysr@777 137 } else {
ysr@777 138 break;
ysr@777 139 }
ysr@777 140 }
ysr@777 141
ysr@777 142 return target_time;
ysr@777 143 }
ysr@777 144
ysr@777 145 // basically the _internal call does not remove expired entries
ysr@777 146 // this is for trying things out in the future and a couple
ysr@777 147 // of other places (debugging)
ysr@777 148
ysr@777 149 double G1MMUTrackerQueue::when_sec(double current_time, double pause_time) {
ysr@777 150 if (_DISABLE_MMU)
ysr@777 151 return 0.0;
ysr@777 152
ysr@777 153 MutexLockerEx x(MMUTracker_lock, Mutex::_no_safepoint_check_flag);
ysr@777 154 remove_expired_entries(current_time);
ysr@777 155
ysr@777 156 return when_internal(current_time, pause_time);
ysr@777 157 }
ysr@777 158
ysr@777 159 double G1MMUTrackerQueue::when_internal(double current_time,
ysr@777 160 double pause_time) {
ysr@777 161 // if the pause is over the maximum, just assume that it's the maximum
ysr@777 162 double adjusted_pause_time =
ysr@777 163 (pause_time > max_gc_time()) ? max_gc_time() : pause_time;
ysr@777 164 double earliest_end = current_time + adjusted_pause_time;
ysr@777 165 double limit = earliest_end - _time_slice;
ysr@777 166 double gc_time = calculate_gc_time(earliest_end);
ysr@777 167 double diff = gc_time + adjusted_pause_time - max_gc_time();
ysr@777 168 if (is_double_leq_0(diff))
ysr@777 169 return 0.0;
ysr@777 170
ysr@777 171 int index = _tail_index;
ysr@777 172 while ( 1 ) {
ysr@777 173 G1MMUTrackerQueueElem *elem = &_array[index];
ysr@777 174 if (elem->end_time() > limit) {
ysr@777 175 if (elem->start_time() > limit)
ysr@777 176 diff -= elem->duration();
ysr@777 177 else
ysr@777 178 diff -= elem->end_time() - limit;
ysr@777 179 if (is_double_leq_0(diff))
ysr@777 180 return elem->end_time() + diff + _time_slice - adjusted_pause_time - current_time;
ysr@777 181 }
ysr@777 182 index = trim_index(index+1);
ysr@777 183 guarantee(index != trim_index(_head_index + 1), "should not go past head");
ysr@777 184 }
ysr@777 185 }

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