1 /*
   2  * Copyright (c) 1997, 2017, 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 "jvm.h"
  27 #include "gc/shared/ageTable.inline.hpp"
  28 #include "gc/shared/ageTableTracer.hpp"
  29 #include "gc/shared/collectedHeap.hpp"
  30 #include "memory/resourceArea.hpp"
  31 #include "logging/log.hpp"
  32 #include "oops/oop.inline.hpp"
  33 #include "utilities/copy.hpp"
  34 
  35 /* Copyright (c) 1992, 2016, Oracle and/or its affiliates, and Stanford University.
  36    See the LICENSE file for license information. */
  37 
  38 AgeTable::AgeTable(bool global) {
  39 
  40   clear();
  41 
  42   if (UsePerfData && global) {
  43 
  44     ResourceMark rm;
  45     EXCEPTION_MARK;
  46 
  47     const char* agetable_ns = "generation.0.agetable";
  48     const char* bytes_ns = PerfDataManager::name_space(agetable_ns, "bytes");
  49 
  50     for(int age = 0; age < table_size; age ++) {
  51       char age_name[10];
  52       jio_snprintf(age_name, sizeof(age_name), "%2.2d", age);
  53       const char* cname = PerfDataManager::counter_name(bytes_ns, age_name);
  54       _perf_sizes[age] = PerfDataManager::create_variable(SUN_GC, cname,
  55                                                           PerfData::U_Bytes,
  56                                                           CHECK);
  57     }
  58 
  59     const char* cname = PerfDataManager::counter_name(agetable_ns, "size");
  60     PerfDataManager::create_constant(SUN_GC, cname, PerfData::U_None,
  61                                      table_size, CHECK);
  62   }
  63 }
  64 
  65 void AgeTable::clear() {
  66   for (size_t* p = sizes; p < sizes + table_size; ++p) {
  67     *p = 0;
  68   }
  69 }
  70 
  71 void AgeTable::merge(AgeTable* subTable) {
  72   for (int i = 0; i < table_size; i++) {
  73     sizes[i]+= subTable->sizes[i];
  74   }
  75 }
  76 
  77 uint AgeTable::compute_tenuring_threshold(size_t desired_survivor_size) {
  78   uint result;
  79 
  80   if (AlwaysTenure || NeverTenure) {
  81     assert(MaxTenuringThreshold == 0 || MaxTenuringThreshold == markWord::max_age + 1,
  82            "MaxTenuringThreshold should be 0 or markWord::max_age + 1, but is " UINTX_FORMAT, MaxTenuringThreshold);
  83     result = MaxTenuringThreshold;
  84   } else {
  85     size_t total = 0;
  86     uint age = 1;
  87     assert(sizes[0] == 0, "no objects with age zero should be recorded");
  88     while (age < table_size) {
  89       total += sizes[age];
  90       // check if including objects of age 'age' made us pass the desired
  91       // size, if so 'age' is the new threshold
  92       if (total > desired_survivor_size) break;
  93       age++;
  94     }
  95     result = age < MaxTenuringThreshold ? age : MaxTenuringThreshold;
  96   }
  97 
  98 
  99   log_debug(gc, age)("Desired survivor size " SIZE_FORMAT " bytes, new threshold " UINTX_FORMAT " (max threshold " UINTX_FORMAT ")",
 100                      desired_survivor_size * oopSize, (uintx) result, MaxTenuringThreshold);
 101 
 102   return result;
 103 }
 104 
 105 void AgeTable::print_age_table(uint tenuring_threshold) {
 106   if (log_is_enabled(Trace, gc, age) || UsePerfData || AgeTableTracer::is_tenuring_distribution_event_enabled()) {
 107     log_trace(gc, age)("Age table with threshold %u (max threshold " UINTX_FORMAT ")",
 108                        tenuring_threshold, MaxTenuringThreshold);
 109 
 110     size_t total = 0;
 111     uint age = 1;
 112     while (age < table_size) {
 113       size_t wordSize = sizes[age];
 114       total += wordSize;
 115       if (wordSize > 0) {
 116         log_trace(gc, age)("- age %3u: " SIZE_FORMAT_W(10) " bytes, " SIZE_FORMAT_W(10) " total",
 117                             age, wordSize * oopSize, total * oopSize);
 118       }
 119       AgeTableTracer::send_tenuring_distribution_event(age, wordSize * oopSize);
 120       if (UsePerfData) {
 121         _perf_sizes[age]->set_value(wordSize * oopSize);
 122       }
 123       age++;
 124     }
 125   }
 126 }
 127