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 

    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 }