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// Copyright 2014 the V8 project authors. All rights reserved. // Use of this source code is governed by a BSD-style license that can be // found in the LICENSE file. #include "src/heap/gc-idle-time-handler.h" #include "src/flags/flags.h" #include "src/heap/gc-tracer.h" #include "src/utils/utils.h" namespace v8 { namespace internal { const double GCIdleTimeHandler::kConservativeTimeRatio = 0.9; const size_t GCIdleTimeHandler::kMaxFinalIncrementalMarkCompactTimeInMs = 1000; const double GCIdleTimeHandler::kHighContextDisposalRate = 100; const size_t GCIdleTimeHandler::kMinTimeForOverApproximatingWeakClosureInMs = 1; void GCIdleTimeHeapState::Print() { PrintF("contexts_disposed=%d ", contexts_disposed); PrintF("contexts_disposal_rate=%f ", contexts_disposal_rate); PrintF("size_of_objects=%zu ", size_of_objects); PrintF("incremental_marking_stopped=%d ", incremental_marking_stopped); } size_t GCIdleTimeHandler::EstimateMarkingStepSize( double idle_time_in_ms, double marking_speed_in_bytes_per_ms) { DCHECK_LT(0, idle_time_in_ms); if (marking_speed_in_bytes_per_ms == 0) { marking_speed_in_bytes_per_ms = kInitialConservativeMarkingSpeed; } double marking_step_size = marking_speed_in_bytes_per_ms * idle_time_in_ms; if (marking_step_size >= kMaximumMarkingStepSize) { return kMaximumMarkingStepSize; } return static_cast<size_t>(marking_step_size * kConservativeTimeRatio); } double GCIdleTimeHandler::EstimateFinalIncrementalMarkCompactTime( size_t size_of_objects, double final_incremental_mark_compact_speed_in_bytes_per_ms) { if (final_incremental_mark_compact_speed_in_bytes_per_ms == 0) { final_incremental_mark_compact_speed_in_bytes_per_ms = kInitialConservativeFinalIncrementalMarkCompactSpeed; } double result = size_of_objects / final_incremental_mark_compact_speed_in_bytes_per_ms; return Min<double>(result, kMaxFinalIncrementalMarkCompactTimeInMs); } bool GCIdleTimeHandler::ShouldDoContextDisposalMarkCompact( int contexts_disposed, double contexts_disposal_rate, size_t size_of_objects) { return contexts_disposed > 0 && contexts_disposal_rate > 0 && contexts_disposal_rate < kHighContextDisposalRate && size_of_objects <= kMaxHeapSizeForContextDisposalMarkCompact; } bool GCIdleTimeHandler::ShouldDoFinalIncrementalMarkCompact( double idle_time_in_ms, size_t size_of_objects, double final_incremental_mark_compact_speed_in_bytes_per_ms) { return idle_time_in_ms >= EstimateFinalIncrementalMarkCompactTime( size_of_objects, final_incremental_mark_compact_speed_in_bytes_per_ms); } bool GCIdleTimeHandler::ShouldDoOverApproximateWeakClosure( double idle_time_in_ms) { // TODO(jochen): Estimate the time it will take to build the object groups. return idle_time_in_ms >= kMinTimeForOverApproximatingWeakClosureInMs; } // The following logic is implemented by the controller: // (1) If we don't have any idle time, do nothing, unless a context was // disposed, incremental marking is stopped, and the heap is small. Then do // a full GC. // (2) If the context disposal rate is high and we cannot perform a full GC, // we do nothing until the context disposal rate becomes lower. // (3) If the new space is almost full and we can afford a scavenge or if the // next scavenge will very likely take long, then a scavenge is performed. // (4) If sweeping is in progress and we received a large enough idle time // request, we finalize sweeping here. // (5) If incremental marking is in progress, we perform a marking step. Note, // that this currently may trigger a full garbage collection. GCIdleTimeAction GCIdleTimeHandler::Compute(double idle_time_in_ms, GCIdleTimeHeapState heap_state) { if (static_cast<int>(idle_time_in_ms) <= 0) { if (heap_state.incremental_marking_stopped) { if (ShouldDoContextDisposalMarkCompact(heap_state.contexts_disposed, heap_state.contexts_disposal_rate, heap_state.size_of_objects)) { return GCIdleTimeAction::kFullGC; } } return GCIdleTimeAction::kDone; } if (FLAG_incremental_marking && !heap_state.incremental_marking_stopped) { return GCIdleTimeAction::kIncrementalStep; } return GCIdleTimeAction::kDone; } bool GCIdleTimeHandler::Enabled() { return FLAG_incremental_marking; } } // namespace internal } // namespace v8