1 /*
   2  * Copyright (c) 1997, 2014, 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_implementation/shared/ageTable.hpp"
  27 #include "gc_implementation/shared/gcPolicyCounters.hpp"
  28 #include "memory/collectorPolicy.hpp"
  29 #include "memory/resourceArea.hpp"
  30 #include "memory/sharedHeap.hpp"
  31 #include "runtime/atomic.inline.hpp"
  32 #include "utilities/copy.hpp"
  33 
  34 /* Copyright (c) 1992-2009 Oracle and/or its affiliates, and Stanford University.
  35    See the LICENSE file for license information. */
  36 
  37 ageTable::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 
  64 void ageTable::clear() {
  65   for (size_t* p = sizes; p < sizes + table_size; ++p) {
  66     *p = 0;
  67   }
  68 }
  69 
  70 void ageTable::merge(ageTable* subTable) {
  71   for (int i = 0; i < table_size; i++) {
  72     sizes[i]+= subTable->sizes[i];
  73   }
  74 }
  75 
  76 void 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 
  82 uint 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 }