ageTable.cpp revision 9056:dc9930a04ab0 
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 "utilities/copy.hpp"
32
33/* Copyright (c) 1992, 2015, Oracle and/or its affiliates, and Stanford University.
34   See the LICENSE file for license information. */
35
36ageTable::ageTable(bool global) {
37
38  clear();
39
40  if (UsePerfData && global) {
41
42    ResourceMark rm;
43    EXCEPTION_MARK;
44
45    const char* agetable_ns = "generation.0.agetable";
46    const char* bytes_ns = PerfDataManager::name_space(agetable_ns, "bytes");
47
48    for(int age = 0; age < table_size; age ++) {
49      char age_name[10];
50      jio_snprintf(age_name, sizeof(age_name), "%2.2d", age);
51      const char* cname = PerfDataManager::counter_name(bytes_ns, age_name);
52      _perf_sizes[age] = PerfDataManager::create_variable(SUN_GC, cname,
53                                                          PerfData::U_Bytes,
54                                                          CHECK);
55    }
56
57    const char* cname = PerfDataManager::counter_name(agetable_ns, "size");
58    PerfDataManager::create_constant(SUN_GC, cname, PerfData::U_None,
59                                     table_size, CHECK);
60  }
61}
62
63void ageTable::clear() {
64  for (size_t* p = sizes; p < sizes + table_size; ++p) {
65    *p = 0;
66  }
67}
68
69void ageTable::merge(ageTable* subTable) {
70  for (int i = 0; i < table_size; i++) {
71    sizes[i]+= subTable->sizes[i];
72  }
73}
74
75uint ageTable::compute_tenuring_threshold(size_t survivor_capacity, GCPolicyCounters* gc_counters) {
76  size_t desired_survivor_size = (size_t)((((double) survivor_capacity)*TargetSurvivorRatio)/100);
77  uint result;
78
79  if (AlwaysTenure || NeverTenure) {
80    assert(MaxTenuringThreshold == 0 || MaxTenuringThreshold == markOopDesc::max_age + 1,
81           "MaxTenuringThreshold should be 0 or markOopDesc::max_age + 1, but is " UINTX_FORMAT, MaxTenuringThreshold);
82    result = MaxTenuringThreshold;
83  } else {
84    size_t total = 0;
85    uint age = 1;
86    assert(sizes[0] == 0, "no objects with age zero should be recorded");
87    while (age < table_size) {
88      total += sizes[age];
89      // check if including objects of age 'age' made us pass the desired
90      // size, if so 'age' is the new threshold
91      if (total > desired_survivor_size) break;
92      age++;
93    }
94    result = age < MaxTenuringThreshold ? age : MaxTenuringThreshold;
95  }
96
97  if (PrintTenuringDistribution || UsePerfData) {
98
99    if (PrintTenuringDistribution) {
100      gclog_or_tty->cr();
101      gclog_or_tty->print_cr("Desired survivor size " SIZE_FORMAT " bytes, new threshold "
102        UINTX_FORMAT " (max threshold " UINTX_FORMAT ")",
103        desired_survivor_size*oopSize, (uintx) result, MaxTenuringThreshold);
104    }
105
106    size_t total = 0;
107    uint age = 1;
108    while (age < table_size) {
109      total += sizes[age];
110      if (sizes[age] > 0) {
111        if (PrintTenuringDistribution) {
112          gclog_or_tty->print_cr("- age %3u: " SIZE_FORMAT_W(10) " bytes, " SIZE_FORMAT_W(10) " total",
113                                        age,    sizes[age]*oopSize,          total*oopSize);
114        }
115      }
116      if (UsePerfData) {
117        _perf_sizes[age]->set_value(sizes[age]*oopSize);
118      }
119      age++;
120    }
121    if (UsePerfData) {
122      gc_counters->tenuring_threshold()->set_value(result);
123      gc_counters->desired_survivor_size()->set_value(
124        desired_survivor_size*oopSize);
125    }
126  }
127
128  return result;
129}
130