ageTable.cpp revision 8413:92457dfb91bd 
1/*
2 * Copyright (c) 1997, 2015, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25#include "precompiled.hpp"
26#include "gc/shared/ageTable.hpp"
27#include "gc/shared/collectedHeap.hpp"
28#include "gc/shared/collectorPolicy.hpp"
29#include "gc/shared/gcPolicyCounters.hpp"
30#include "memory/resourceArea.hpp"
31#include "runtime/atomic.inline.hpp"
32#include "utilities/copy.hpp"
33
34/* Copyright (c) 1992, 2015, Oracle and/or its affiliates, and Stanford University.
35   See the LICENSE file for license information. */
36
37ageTable::ageTable(bool global) {
38
39  clear();
40
41  if (UsePerfData && global) {
42
43    ResourceMark rm;
44    EXCEPTION_MARK;
45
46    const char* agetable_ns = "generation.0.agetable";
47    const char* bytes_ns = PerfDataManager::name_space(agetable_ns, "bytes");
48
49    for(int age = 0; age < table_size; age ++) {
50      char age_name[10];
51      jio_snprintf(age_name, sizeof(age_name), "%2.2d", age);
52      const char* cname = PerfDataManager::counter_name(bytes_ns, age_name);
53      _perf_sizes[age] = PerfDataManager::create_variable(SUN_GC, cname,
54                                                          PerfData::U_Bytes,
55                                                          CHECK);
56    }
57
58    const char* cname = PerfDataManager::counter_name(agetable_ns, "size");
59    PerfDataManager::create_constant(SUN_GC, cname, PerfData::U_None,
60                                     table_size, CHECK);
61  }
62}
63
64void ageTable::clear() {
65  for (size_t* p = sizes; p < sizes + table_size; ++p) {
66    *p = 0;
67  }
68}
69
70void ageTable::merge(ageTable* subTable) {
71  for (int i = 0; i < table_size; i++) {
72    sizes[i]+= subTable->sizes[i];
73  }
74}
75
76void ageTable::merge_par(ageTable* subTable) {
77  for (int i = 0; i < table_size; i++) {
78    Atomic::add_ptr(subTable->sizes[i], &sizes[i]);
79  }
80}
81
82uint ageTable::compute_tenuring_threshold(size_t survivor_capacity, GCPolicyCounters* gc_counters) {
83  size_t desired_survivor_size = (size_t)((((double) survivor_capacity)*TargetSurvivorRatio)/100);
84  uint result;
85
86  if (AlwaysTenure || NeverTenure) {
87    assert(MaxTenuringThreshold == 0 || MaxTenuringThreshold == markOopDesc::max_age + 1,
88        err_msg("MaxTenuringThreshold should be 0 or markOopDesc::max_age + 1, but is " UINTX_FORMAT, MaxTenuringThreshold));
89    result = MaxTenuringThreshold;
90  } else {
91    size_t total = 0;
92    uint age = 1;
93    assert(sizes[0] == 0, "no objects with age zero should be recorded");
94    while (age < table_size) {
95      total += sizes[age];
96      // check if including objects of age 'age' made us pass the desired
97      // size, if so 'age' is the new threshold
98      if (total > desired_survivor_size) break;
99      age++;
100    }
101    result = age < MaxTenuringThreshold ? age : MaxTenuringThreshold;
102  }
103
104  if (PrintTenuringDistribution || UsePerfData) {
105
106    if (PrintTenuringDistribution) {
107      gclog_or_tty->cr();
108      gclog_or_tty->print_cr("Desired survivor size " SIZE_FORMAT " bytes, new threshold "
109        UINTX_FORMAT " (max threshold " UINTX_FORMAT ")",
110        desired_survivor_size*oopSize, (uintx) result, MaxTenuringThreshold);
111    }
112
113    size_t total = 0;
114    uint age = 1;
115    while (age < table_size) {
116      total += sizes[age];
117      if (sizes[age] > 0) {
118        if (PrintTenuringDistribution) {
119          gclog_or_tty->print_cr("- age %3u: " SIZE_FORMAT_W(10) " bytes, " SIZE_FORMAT_W(10) " total",
120                                        age,    sizes[age]*oopSize,          total*oopSize);
121        }
122      }
123      if (UsePerfData) {
124        _perf_sizes[age]->set_value(sizes[age]*oopSize);
125      }
126      age++;
127    }
128    if (UsePerfData) {
129      gc_counters->tenuring_threshold()->set_value(result);
130      gc_counters->desired_survivor_size()->set_value(
131        desired_survivor_size*oopSize);
132    }
133  }
134
135  return result;
136}
137