/*

 * Copyright 2001-2007 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 *

 */

#include "incls/_precompiled.incl"

#include "incls/_concurrentG1Refine.cpp.incl"

bool ConcurrentG1Refine::_enabled = false;

ConcurrentG1Refine::ConcurrentG1Refine() :

  _pya(PYA_continue), _last_pya(PYA_continue),

  _last_cards_during(), _first_traversal(false),

  _card_counts(NULL), _cur_card_count_histo(NULL), _cum_card_count_histo(NULL),

  _hot_cache(NULL),

  _def_use_cache(false), _use_cache(false),

  _n_periods(0), _total_cards(0), _total_travs(0)

{

  if (G1ConcRefine) {

    _cg1rThread = new ConcurrentG1RefineThread(this);

    assert(cg1rThread() != NULL, "Conc refine should have been created");

    assert(cg1rThread()->cg1r() == this,

           "Conc refine thread should refer to this");

  } else {

    _cg1rThread = NULL;

  }

}

void ConcurrentG1Refine::init() {

  if (G1ConcRSLogCacheSize > 0 || G1ConcRSCountTraversals) {

    G1CollectedHeap* g1h = G1CollectedHeap::heap();

    _n_card_counts =

      (unsigned) (g1h->g1_reserved_obj_bytes() >> CardTableModRefBS::card_shift);

    _card_counts = NEW_C_HEAP_ARRAY(unsigned char, _n_card_counts);

    for (size_t i = 0; i < _n_card_counts; i++) _card_counts[i] = 0;

    ModRefBarrierSet* bs = g1h->mr_bs();

    guarantee(bs->is_a(BarrierSet::CardTableModRef), "Precondition");

    CardTableModRefBS* ctbs = (CardTableModRefBS*)bs;

    _ct_bot = ctbs->byte_for_const(g1h->reserved_region().start());

    if (G1ConcRSCountTraversals) {

      _cur_card_count_histo = NEW_C_HEAP_ARRAY(unsigned, 256);

      _cum_card_count_histo = NEW_C_HEAP_ARRAY(unsigned, 256);

      for (int i = 0; i < 256; i++) {

        _cur_card_count_histo[i] = 0;

        _cum_card_count_histo[i] = 0;

      }

    }

  }

  if (G1ConcRSLogCacheSize > 0) {

    _def_use_cache = true;

    _use_cache = true;

    _hot_cache_size = (1 << G1ConcRSLogCacheSize);

    _hot_cache = NEW_C_HEAP_ARRAY(jbyte*, _hot_cache_size);

    _n_hot = 0;

    _hot_cache_idx = 0;

  }

}

ConcurrentG1Refine::~ConcurrentG1Refine() {

  if (G1ConcRSLogCacheSize > 0 || G1ConcRSCountTraversals) {

    assert(_card_counts != NULL, "Logic");

    FREE_C_HEAP_ARRAY(unsigned char, _card_counts);

    assert(_cur_card_count_histo != NULL, "Logic");

    FREE_C_HEAP_ARRAY(unsigned, _cur_card_count_histo);

    assert(_cum_card_count_histo != NULL, "Logic");

    FREE_C_HEAP_ARRAY(unsigned, _cum_card_count_histo);

  }

  if (G1ConcRSLogCacheSize > 0) {

    assert(_hot_cache != NULL, "Logic");

    FREE_C_HEAP_ARRAY(jbyte*, _hot_cache);

  }

}

bool ConcurrentG1Refine::refine() {

  G1CollectedHeap* g1h = G1CollectedHeap::heap();

  unsigned cards_before = g1h->g1_rem_set()->conc_refine_cards();

  clear_hot_cache();  // Any previous values in this are now invalid.

  g1h->g1_rem_set()->concurrentRefinementPass(this);

  _traversals++;

  unsigned cards_after = g1h->g1_rem_set()->conc_refine_cards();

  unsigned cards_during = cards_after-cards_before;

  // If this is the first traversal in the current enabling

  // and we did some cards, or if the number of cards found is decreasing

  // sufficiently quickly, then keep going.  Otherwise, sleep a while.

  bool res =

    (_first_traversal && cards_during > 0)

    ||

    (!_first_traversal && cards_during * 3 < _last_cards_during * 2);

  _last_cards_during = cards_during;

  _first_traversal = false;

  return res;

}

void ConcurrentG1Refine::enable() {

  MutexLocker x(G1ConcRefine_mon);

  if (!_enabled) {

    _enabled = true;

    _first_traversal = true; _last_cards_during = 0;

    G1ConcRefine_mon->notify_all();

  }

}

unsigned ConcurrentG1Refine::disable() {

  MutexLocker x(G1ConcRefine_mon);

  if (_enabled) {

    _enabled = false;

    return _traversals;

  } else {

    return 0;

  }

}

void ConcurrentG1Refine::wait_for_ConcurrentG1Refine_enabled() {

  G1ConcRefine_mon->lock();

  while (!_enabled) {

    G1ConcRefine_mon->wait(Mutex::_no_safepoint_check_flag);

  }

  G1ConcRefine_mon->unlock();

  _traversals = 0;

};

void ConcurrentG1Refine::set_pya_restart() {

  // If we're using the log-based RS barrier, the above will cause

  // in-progress traversals of completed log buffers to quit early; we will

  // also abandon all other buffers.

  if (G1RSBarrierUseQueue) {

    DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();

    dcqs.abandon_logs();

    if (_cg1rThread->do_traversal()) {

      _pya = PYA_restart;

    } else {

      _cg1rThread->set_do_traversal(true);

      // Reset the post-yield actions.

      _pya = PYA_continue;

      _last_pya = PYA_continue;

    }

  } else {

    _pya = PYA_restart;

  }

}

void ConcurrentG1Refine::set_pya_cancel() {

  _pya = PYA_cancel;

}

PostYieldAction ConcurrentG1Refine::get_pya() {

  if (_pya != PYA_continue) {

    jint val = _pya;

    while (true) {

      jint val_read = Atomic::cmpxchg(PYA_continue, &_pya, val);

      if (val_read == val) {

        PostYieldAction res = (PostYieldAction)val;

        assert(res != PYA_continue, "Only the refine thread should reset.");

        _last_pya = res;

        return res;

      } else {

        val = val_read;

      }

    }

  }

  // QQQ WELL WHAT DO WE RETURN HERE???

  // make up something!

  return PYA_continue;

}

PostYieldAction ConcurrentG1Refine::get_last_pya() {

  PostYieldAction res = _last_pya;

  _last_pya = PYA_continue;

  return res;

}

bool ConcurrentG1Refine::do_traversal() {

  return _cg1rThread->do_traversal();

}

int ConcurrentG1Refine::add_card_count(jbyte* card_ptr) {

  size_t card_num = (card_ptr - _ct_bot);

  guarantee(0 <= card_num && card_num < _n_card_counts, "Bounds");

  unsigned char cnt = _card_counts[card_num];

  if (cnt < 255) _card_counts[card_num]++;

  return cnt;

  _total_travs++;

}

jbyte* ConcurrentG1Refine::cache_insert(jbyte* card_ptr) {

  int count = add_card_count(card_ptr);

  // Count previously unvisited cards.

  if (count == 0) _total_cards++;

  // We'll assume a traversal unless we store it in the cache.

  if (count < G1ConcRSHotCardLimit) {

    _total_travs++;

    return card_ptr;

  }

  // Otherwise, it's hot.

  jbyte* res = NULL;

  MutexLockerEx x(HotCardCache_lock, Mutex::_no_safepoint_check_flag);

  if (_n_hot == _hot_cache_size) {

    _total_travs++;

    res = _hot_cache[_hot_cache_idx];

    _n_hot--;

  }

  // Now _n_hot < _hot_cache_size, and we can insert at _hot_cache_idx.

  _hot_cache[_hot_cache_idx] = card_ptr;

  _hot_cache_idx++;

  if (_hot_cache_idx == _hot_cache_size) _hot_cache_idx = 0;

  _n_hot++;

  return res;

}

void ConcurrentG1Refine::clean_up_cache(int worker_i, G1RemSet* g1rs) {

  assert(!use_cache(), "cache should be disabled");

  int start_ind = _hot_cache_idx-1;

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

    int ind = start_ind - i;

    if (ind < 0) ind = ind + _hot_cache_size;

    jbyte* entry = _hot_cache[ind];

    if (entry != NULL) {

      g1rs->concurrentRefineOneCard(entry, worker_i);

    }

  }

  _n_hot = 0;

  _hot_cache_idx = 0;

}

void ConcurrentG1Refine::clear_and_record_card_counts() {

  if (G1ConcRSLogCacheSize == 0 && !G1ConcRSCountTraversals) return;

  _n_periods++;

  if (G1ConcRSCountTraversals) {

    for (size_t i = 0; i < _n_card_counts; i++) {

      unsigned char bucket = _card_counts[i];

      _cur_card_count_histo[bucket]++;

      _card_counts[i] = 0;

    }

    gclog_or_tty->print_cr("Card counts:");

    for (int i = 0; i < 256; i++) {

      if (_cur_card_count_histo[i] > 0) {

        gclog_or_tty->print_cr("  %3d: %9d", i, _cur_card_count_histo[i]);

        _cum_card_count_histo[i] += _cur_card_count_histo[i];

        _cur_card_count_histo[i] = 0;

      }

    }

  } else {

    assert(G1ConcRSLogCacheSize > 0, "Logic");

    Copy::fill_to_words((HeapWord*)(&_card_counts[0]),

                        _n_card_counts / HeapWordSize);

  }

}

void

ConcurrentG1Refine::

print_card_count_histo_range(unsigned* histo, int from, int to,

                             float& cum_card_pct,

                             float& cum_travs_pct) {

  unsigned cards = 0;

  unsigned travs = 0;

  guarantee(to <= 256, "Precondition");

  for (int i = from; i < to-1; i++) {

    cards += histo[i];

    travs += histo[i] * i;

  }

  if (to == 256) {

    unsigned histo_card_sum = 0;

    unsigned histo_trav_sum = 0;

    for (int i = 1; i < 255; i++) {

      histo_trav_sum += histo[i] * i;

    }

    cards += histo[255];

    // correct traversals for the last one.

    unsigned travs_255 = (unsigned) (_total_travs - histo_trav_sum);

    travs += travs_255;

  } else {

    cards += histo[to-1];

    travs += histo[to-1] * (to-1);

  }

  float fperiods = (float)_n_periods;

  float f_tot_cards = (float)_total_cards/fperiods;

  float f_tot_travs = (float)_total_travs/fperiods;

  if (cards > 0) {

    float fcards = (float)cards/fperiods;

    float ftravs = (float)travs/fperiods;

    if (to == 256) {

      gclog_or_tty->print(" %4d-       %10.2f%10.2f", from, fcards, ftravs);

    } else {

      gclog_or_tty->print(" %4d-%4d   %10.2f%10.2f", from, to-1, fcards, ftravs);

    }

    float pct_cards = fcards*100.0/f_tot_cards;

    cum_card_pct += pct_cards;

    float pct_travs = ftravs*100.0/f_tot_travs;

    cum_travs_pct += pct_travs;

    gclog_or_tty->print_cr("%10.2f%10.2f%10.2f%10.2f",

                  pct_cards, cum_card_pct,

                  pct_travs, cum_travs_pct);

  }

}

void ConcurrentG1Refine::print_final_card_counts() {

  if (!G1ConcRSCountTraversals) return;

  gclog_or_tty->print_cr("Did %d total traversals of %d distinct cards.",

                _total_travs, _total_cards);

  float fperiods = (float)_n_periods;

  gclog_or_tty->print_cr("  This is an average of %8.2f traversals, %8.2f cards, "

                "per collection.", (float)_total_travs/fperiods,

                (float)_total_cards/fperiods);

  gclog_or_tty->print_cr("  This is an average of %8.2f traversals/distinct "

                "dirty card.\n",

                _total_cards > 0 ?

                (float)_total_travs/(float)_total_cards : 0.0);

  gclog_or_tty->print_cr("Histogram:\n\n%10s   %10s%10s%10s%10s%10s%10s",

                "range", "# cards", "# travs", "% cards", "(cum)",

                "% travs", "(cum)");

  gclog_or_tty->print_cr("------------------------------------------------------------"

                "-------------");

  float cum_cards_pct = 0.0;

  float cum_travs_pct = 0.0;

  for (int i = 1; i < 10; i++) {

    print_card_count_histo_range(_cum_card_count_histo, i, i+1,

                                 cum_cards_pct, cum_travs_pct);

  }

  for (int i = 10; i < 100; i += 10) {

    print_card_count_histo_range(_cum_card_count_histo, i, i+10,

                                 cum_cards_pct, cum_travs_pct);

  }

  print_card_count_histo_range(_cum_card_count_histo, 100, 150,

                               cum_cards_pct, cum_travs_pct);

  print_card_count_histo_range(_cum_card_count_histo, 150, 200,

                               cum_cards_pct, cum_travs_pct);

  print_card_count_histo_range(_cum_card_count_histo, 150, 255,

                               cum_cards_pct, cum_travs_pct);

  print_card_count_histo_range(_cum_card_count_histo, 255, 256,

                               cum_cards_pct, cum_travs_pct);

}