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 
  36 ageTable::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 
  63 void ageTable::clear() {
  64   for (size_t* p = sizes; p < sizes + table_size; ++p) {
  65     *p = 0;
  66   }
  67 }
  68 
  69 void ageTable::merge(ageTable* subTable) {
  70   for (int i = 0; i < table_size; i++) {
  71     sizes[i]+= subTable->sizes[i];
  72   }
  73 }
  74 
  75 uint 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 }
--- EOF ---