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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. #ifndef V8_HEAP_GC_IDLE_TIME_HANDLER_H_ #define V8_HEAP_GC_IDLE_TIME_HANDLER_H_ #include "src/common/globals.h" namespace v8 { namespace internal { enum class GCIdleTimeAction : uint8_t { kDone, kIncrementalStep, kFullGC, }; class GCIdleTimeHeapState { public: void Print(); int contexts_disposed; double contexts_disposal_rate; size_t size_of_objects; bool incremental_marking_stopped; }; // The idle time handler makes decisions about which garbage collection // operations are executing during IdleNotification. class V8_EXPORT_PRIVATE GCIdleTimeHandler { public: // If we haven't recorded any incremental marking events yet, we carefully // mark with a conservative lower bound for the marking speed. static const size_t kInitialConservativeMarkingSpeed = 100 * KB; // Maximum marking step size returned by EstimateMarkingStepSize. static const size_t kMaximumMarkingStepSize = 700 * MB; // We have to make sure that we finish the IdleNotification before // idle_time_in_ms. Hence, we conservatively prune our workload estimate. static const double kConservativeTimeRatio; // If we haven't recorded any mark-compact events yet, we use // conservative lower bound for the mark-compact speed. static const size_t kInitialConservativeMarkCompactSpeed = 2 * MB; // If we haven't recorded any final incremental mark-compact events yet, we // use conservative lower bound for the mark-compact speed. static const size_t kInitialConservativeFinalIncrementalMarkCompactSpeed = 2 * MB; // Maximum final incremental mark-compact time returned by // EstimateFinalIncrementalMarkCompactTime. static const size_t kMaxFinalIncrementalMarkCompactTimeInMs; // This is the maximum scheduled idle time. Note that it can be more than // 16.66 ms when there is currently no rendering going on. static const size_t kMaxScheduledIdleTime = 50; // The maximum idle time when frames are rendered is 16.66ms. static const size_t kMaxFrameRenderingIdleTime = 17; static const int kMinBackgroundIdleTime = 900; // An allocation throughput below kLowAllocationThroughput bytes/ms is // considered low static const size_t kLowAllocationThroughput = 1000; static const size_t kMaxHeapSizeForContextDisposalMarkCompact = 100 * MB; // If contexts are disposed at a higher rate a full gc is triggered. static const double kHighContextDisposalRate; // Incremental marking step time. static const size_t kIncrementalMarkingStepTimeInMs = 1; static const size_t kMinTimeForOverApproximatingWeakClosureInMs; GCIdleTimeHandler() = default; GCIdleTimeAction Compute(double idle_time_in_ms, GCIdleTimeHeapState heap_state); bool Enabled(); static size_t EstimateMarkingStepSize(double idle_time_in_ms, double marking_speed_in_bytes_per_ms); static double EstimateFinalIncrementalMarkCompactTime( size_t size_of_objects, double mark_compact_speed_in_bytes_per_ms); static bool ShouldDoContextDisposalMarkCompact(int context_disposed, double contexts_disposal_rate, size_t size_of_objects); static bool ShouldDoFinalIncrementalMarkCompact( double idle_time_in_ms, size_t size_of_objects, double final_incremental_mark_compact_speed_in_bytes_per_ms); static bool ShouldDoOverApproximateWeakClosure(double idle_time_in_ms); private: DISALLOW_COPY_AND_ASSIGN(GCIdleTimeHandler); }; } // namespace internal } // namespace v8 #endif // V8_HEAP_GC_IDLE_TIME_HANDLER_H_