/*
 * Copyright (c) 2017, 2019, Red Hat, Inc. All rights reserved.
 *
 * 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 "jfr/jfrEvents.hpp"
#include "gc/shared/gcCause.hpp"
#include "gc/shared/gcTimer.hpp"
#include "gc/shared/gcTrace.hpp"
#include "gc/shared/gcWhen.hpp"
#include "gc/shenandoah/shenandoahAllocTracker.hpp"
#include "gc/shenandoah/shenandoahCollectorPolicy.hpp"
#include "gc/shenandoah/shenandoahMarkCompact.hpp"
#include "gc/shenandoah/shenandoahHeap.hpp"
#include "gc/shenandoah/shenandoahHeuristics.hpp"
#include "gc/shenandoah/shenandoahUtils.hpp"
#include "utilities/debug.hpp"

ShenandoahPhaseTimings::Phase ShenandoahGCPhase::_current_phase = ShenandoahGCPhase::_invalid_phase;

ShenandoahGCSession::ShenandoahGCSession(GCCause::Cause cause) :
  _heap(ShenandoahHeap::heap()),
  _timer(_heap->gc_timer()),
  _tracer(_heap->tracer()) {
  assert(!ShenandoahGCPhase::is_valid_phase(ShenandoahGCPhase::current_phase()),
    "No current GC phase");

  _heap->set_gc_cause(cause);
  _timer->register_gc_start();
  _tracer->report_gc_start(cause, _timer->gc_start());
  _heap->trace_heap(GCWhen::BeforeGC, _tracer);

  _heap->shenandoah_policy()->record_cycle_start();
  _heap->heuristics()->record_cycle_start();
  _trace_cycle.initialize(_heap->cycle_memory_manager(), cause,
          /* allMemoryPoolsAffected */    true,
          /* recordGCBeginTime = */       true,
          /* recordPreGCUsage = */        true,
          /* recordPeakUsage = */         true,
          /* recordPostGCUsage = */       true,
          /* recordAccumulatedGCTime = */ true,
          /* recordGCEndTime = */         true,
          /* countCollection = */         true
  );
}

ShenandoahGCSession::~ShenandoahGCSession() {
  _heap->heuristics()->record_cycle_end();
  _timer->register_gc_end();
  _heap->trace_heap(GCWhen::AfterGC, _tracer);
  _tracer->report_gc_end(_timer->gc_end(), _timer->time_partitions());
  assert(!ShenandoahGCPhase::is_valid_phase(ShenandoahGCPhase::current_phase()),
    "No current GC phase");
  _heap->set_gc_cause(GCCause::_no_gc);
}

ShenandoahGCPauseMark::ShenandoahGCPauseMark(uint gc_id, SvcGCMarker::reason_type type) :
  _heap(ShenandoahHeap::heap()), _gc_id_mark(gc_id), _svc_gc_mark(type), _is_gc_active_mark() {

  // FIXME: It seems that JMC throws away level 0 events, which are the Shenandoah
  // pause events. Create this pseudo level 0 event to push real events to level 1.
  _heap->gc_timer()->register_gc_phase_start("Shenandoah", Ticks::now());
  _trace_pause.initialize(_heap->stw_memory_manager(), _heap->gc_cause(),
          /* allMemoryPoolsAffected */    true,
          /* recordGCBeginTime = */       true,
          /* recordPreGCUsage = */        false,
          /* recordPeakUsage = */         false,
          /* recordPostGCUsage = */       false,
          /* recordAccumulatedGCTime = */ true,
          /* recordGCEndTime = */         true,
          /* countCollection = */         true
  );

  _heap->heuristics()->record_gc_start();
}

ShenandoahGCPauseMark::~ShenandoahGCPauseMark() {
  _heap->gc_timer()->register_gc_phase_end(Ticks::now());
  _heap->heuristics()->record_gc_end();
}

ShenandoahGCPhase::ShenandoahGCPhase(const ShenandoahPhaseTimings::Phase phase) :
  _heap(ShenandoahHeap::heap()), _phase(phase) {
   assert(!Thread::current()->is_Worker_thread() &&
              (Thread::current()->is_VM_thread() ||
               Thread::current()->is_ConcurrentGC_thread()),
          "Must be set by these threads");
  _parent_phase = _current_phase;
  _current_phase = phase;

  _heap->phase_timings()->record_phase_start(_phase);
}

ShenandoahGCPhase::~ShenandoahGCPhase() {
  _heap->phase_timings()->record_phase_end(_phase);
  _current_phase = _parent_phase;
}

bool ShenandoahGCPhase::is_valid_phase(ShenandoahPhaseTimings::Phase phase) {
  return phase >= 0 && phase < ShenandoahPhaseTimings::_num_phases;
}

bool ShenandoahGCPhase::is_root_work_phase() {
  switch(current_phase()) {
    case ShenandoahPhaseTimings::scan_roots:
    case ShenandoahPhaseTimings::update_roots:
    case ShenandoahPhaseTimings::init_evac:
    case ShenandoahPhaseTimings::final_update_refs_roots:
    case ShenandoahPhaseTimings::degen_gc_update_roots:
    case ShenandoahPhaseTimings::init_traversal_gc_work:
    case ShenandoahPhaseTimings::final_traversal_gc_work:
    case ShenandoahPhaseTimings::final_traversal_update_roots:
    case ShenandoahPhaseTimings::full_gc_roots:
      return true;
    default:
      return false;
  }
}

ShenandoahAllocTrace::ShenandoahAllocTrace(size_t words_size, ShenandoahAllocRequest::Type alloc_type) {
  if (ShenandoahAllocationTrace) {
    _start = os::elapsedTime();
    _size = words_size;
    _alloc_type = alloc_type;
  } else {
    _start = 0;
    _size = 0;
    _alloc_type = ShenandoahAllocRequest::Type(0);
  }
}

ShenandoahAllocTrace::~ShenandoahAllocTrace() {
  if (ShenandoahAllocationTrace) {
    double stop = os::elapsedTime();
    double duration_sec = stop - _start;
    double duration_us = duration_sec * 1000000;
    ShenandoahAllocTracker* tracker = ShenandoahHeap::heap()->alloc_tracker();
    assert(tracker != NULL, "Must be");
    tracker->record_alloc_latency(_size, _alloc_type, duration_us);
    if (duration_us > ShenandoahAllocationStallThreshold) {
      log_warning(gc)("Allocation stall: %.0f us (threshold: " INTX_FORMAT " us)",
                      duration_us, ShenandoahAllocationStallThreshold);
    }
  }
}

ShenandoahWorkerSession::ShenandoahWorkerSession(uint worker_id) : _worker_id(worker_id) {
  Thread* thr = Thread::current();
  assert(ShenandoahThreadLocalData::worker_id(thr) == ShenandoahThreadLocalData::INVALID_WORKER_ID, "Already set");
  ShenandoahThreadLocalData::set_worker_id(thr, worker_id);
}

ShenandoahConcurrentWorkerSession::~ShenandoahConcurrentWorkerSession() {
  _event.commit(GCId::current(), ShenandoahPhaseTimings::phase_name(ShenandoahGCPhase::current_phase()));
}

ShenandoahParallelWorkerSession::~ShenandoahParallelWorkerSession() {
  _event.commit(GCId::current(), _worker_id, ShenandoahPhaseTimings::phase_name(ShenandoahGCPhase::current_phase()));
}
ShenandoahWorkerSession::~ShenandoahWorkerSession() {
#ifdef ASSERT
  Thread* thr = Thread::current();
  assert(ShenandoahThreadLocalData::worker_id(thr) != ShenandoahThreadLocalData::INVALID_WORKER_ID, "Must be set");
  ShenandoahThreadLocalData::set_worker_id(thr, ShenandoahThreadLocalData::INVALID_WORKER_ID);
#endif
}

struct PhaseMap {
   WeakProcessorPhases::Phase            _weak_processor_phase;
   ShenandoahPhaseTimings::GCParPhases   _shenandoah_phase;
};

static const struct PhaseMap phase_mapping[] = {
#if INCLUDE_JVMTI
  {WeakProcessorPhases::jvmti,                 ShenandoahPhaseTimings::JVMTIWeakRoots},
#endif
#if INCLUDE_JFR
  {WeakProcessorPhases::jfr,                   ShenandoahPhaseTimings::JFRWeakRoots},
#endif
  {WeakProcessorPhases::jni,                   ShenandoahPhaseTimings::JNIWeakRoots},
  {WeakProcessorPhases::stringtable,           ShenandoahPhaseTimings::StringTableRoots},
  {WeakProcessorPhases::resolved_method_table, ShenandoahPhaseTimings::ResolvedMethodTableRoots},
  {WeakProcessorPhases::vm,                    ShenandoahPhaseTimings::VMWeakRoots},
  {WeakProcessorPhases::nmethod_keepalive,     ShenandoahPhaseTimings::NMethodKeepAliveRoots}
};

STATIC_ASSERT(sizeof(phase_mapping) / sizeof(PhaseMap) == WeakProcessorPhases::phase_count);

void ShenandoahTimingConverter::weak_processing_timing_to_shenandoah_timing(WeakProcessorPhaseTimes* weak_processing_timings,
                                                                            ShenandoahWorkerTimings* sh_worker_times) {
  assert(weak_processing_timings->max_threads() == weak_processing_timings->max_threads(), "Must match");
  for (uint index = 0; index < WeakProcessorPhases::phase_count; index ++) {
    weak_processing_phase_to_shenandoah_phase(phase_mapping[index]._weak_processor_phase,
                                              weak_processing_timings,
                                              phase_mapping[index]._shenandoah_phase,
                                              sh_worker_times);
  }
}

void ShenandoahTimingConverter::weak_processing_phase_to_shenandoah_phase(WeakProcessorPhases::Phase wpp,
                                                                          WeakProcessorPhaseTimes* weak_processing_timings,
                                                                          ShenandoahPhaseTimings::GCParPhases spp,
                                                                          ShenandoahWorkerTimings* sh_worker_times) {
  if (WeakProcessorPhases::is_serial(wpp)) {
    sh_worker_times->record_time_secs(spp, 0, weak_processing_timings->phase_time_sec(wpp));
  } else {
    for (uint index = 0; index < weak_processing_timings->max_threads(); index ++) {
      sh_worker_times->record_time_secs(spp, index, weak_processing_timings->worker_time_sec(index, wpp));
    }
  }
}