/*

 * Copyright (c) 1997, 2016, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 *

 */

#include "precompiled.hpp"

#include "gc/shared/ageTable.inline.hpp"

#include "gc/shared/ageTableTracer.hpp"

#include "gc/shared/collectedHeap.hpp"

#include "gc/shared/collectorPolicy.hpp"

#include "gc/shared/gcPolicyCounters.hpp"

#include "memory/resourceArea.hpp"

#include "logging/log.hpp"

#include "oops/oop.inline.hpp"

#include "utilities/copy.hpp"

/* Copyright (c) 1992, 2016, Oracle and/or its affiliates, and Stanford University.

   See the LICENSE file for license information. */

AgeTable::AgeTable(bool global) {

  clear();

  if (UsePerfData && global) {

    ResourceMark rm;

    EXCEPTION_MARK;

    const char* agetable_ns = "generation.0.agetable";

    const char* bytes_ns = PerfDataManager::name_space(agetable_ns, "bytes");

    for(int age = 0; age < table_size; age ++) {

      char age_name[10];

      jio_snprintf(age_name, sizeof(age_name), "%2.2d", age);

      const char* cname = PerfDataManager::counter_name(bytes_ns, age_name);

      _perf_sizes[age] = PerfDataManager::create_variable(SUN_GC, cname,

                                                          PerfData::U_Bytes,

                                                          CHECK);

    }

    const char* cname = PerfDataManager::counter_name(agetable_ns, "size");

    PerfDataManager::create_constant(SUN_GC, cname, PerfData::U_None,

                                     table_size, CHECK);

  }

}

void AgeTable::clear() {

  for (size_t* p = sizes; p < sizes + table_size; ++p) {

    *p = 0;

  }

}

void AgeTable::merge(AgeTable* subTable) {

  for (int i = 0; i < table_size; i++) {

    sizes[i]+= subTable->sizes[i];

  }

}

uint AgeTable::compute_tenuring_threshold(size_t survivor_capacity, GCPolicyCounters* gc_counters) {

  size_t desired_survivor_size = (size_t)((((double) survivor_capacity)*TargetSurvivorRatio)/100);

  uint result;

  if (AlwaysTenure || NeverTenure) {

    assert(MaxTenuringThreshold == 0 || MaxTenuringThreshold == markOopDesc::max_age + 1,

           "MaxTenuringThreshold should be 0 or markOopDesc::max_age + 1, but is " UINTX_FORMAT, MaxTenuringThreshold);

    result = MaxTenuringThreshold;

  } else {

    size_t total = 0;

    uint age = 1;

    assert(sizes[0] == 0, "no objects with age zero should be recorded");

    while (age < table_size) {

      total += sizes[age];

      // check if including objects of age 'age' made us pass the desired

      // size, if so 'age' is the new threshold

      if (total > desired_survivor_size) break;

      age++;

    }

    result = age < MaxTenuringThreshold ? age : MaxTenuringThreshold;

  }

  log_debug(gc, age)("Desired survivor size " SIZE_FORMAT " bytes, new threshold " UINTX_FORMAT " (max threshold " UINTX_FORMAT ")",

                     desired_survivor_size*oopSize, (uintx) result, MaxTenuringThreshold);

  if (log_is_enabled(Trace, gc, age) || UsePerfData || AgeTableTracer::is_tenuring_distribution_event_enabled()) {

    size_t total = 0;

    uint age = 1;

    while (age < table_size) {

      size_t wordSize = sizes[age];

      total += wordSize;

      if (wordSize > 0) {

        log_trace(gc, age)("- age %3u: " SIZE_FORMAT_W(10) " bytes, " SIZE_FORMAT_W(10) " total",

                            age, wordSize*oopSize, total*oopSize);

      }

      AgeTableTracer::send_tenuring_distribution_event(age, wordSize*oopSize);

      if (UsePerfData) {

        _perf_sizes[age]->set_value(wordSize*oopSize);

      }

      age++;

    }

    if (UsePerfData) {

      gc_counters->tenuring_threshold()->set_value(result);

      gc_counters->desired_survivor_size()->set_value(

        desired_survivor_size*oopSize);

    }

  }

  return result;

}