1 // Copyright 2015 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #ifndef BASE_TRACE_EVENT_HEAP_PROFILER_HEAP_DUMP_WRITER_H_ 6 #define BASE_TRACE_EVENT_HEAP_PROFILER_HEAP_DUMP_WRITER_H_ 7 8 #include <stddef.h> 9 10 #include <memory> 11 #include <set> 12 13 #include "base/base_export.h" 14 #include "base/containers/hash_tables.h" 15 #include "base/macros.h" 16 #include "base/trace_event/heap_profiler_allocation_context.h" 17 18 namespace base { 19 namespace trace_event { 20 21 class MemoryDumpSessionState; 22 class StackFrameDeduplicator; 23 class TracedValue; 24 class TypeNameDeduplicator; 25 26 // Aggregates |metrics_by_context|, recursively breaks down the heap, and 27 // returns a traced value with an "entries" array that can be dumped in the 28 // trace log, following the format described in https://goo.gl/KY7zVE. The 29 // number of entries is kept reasonable because long tails are not included. 30 BASE_EXPORT std::unique_ptr<TracedValue> ExportHeapDump( 31 const hash_map<AllocationContext, AllocationMetrics>& metrics_by_context, 32 const MemoryDumpSessionState& session_state); 33 34 namespace internal { 35 36 namespace { 37 struct Bucket; 38 } 39 40 // An entry in the "entries" array as described in https://goo.gl/KY7zVE. 41 struct BASE_EXPORT Entry { 42 size_t size; 43 size_t count; 44 45 // References a backtrace in the stack frame deduplicator. -1 means empty 46 // backtrace (the root of the tree). 47 int stack_frame_id; 48 49 // References a type name in the type name deduplicator. -1 indicates that 50 // the size is the cumulative size for all types (the root of the tree). 51 int type_id; 52 }; 53 54 // Comparison operator to enable putting |Entry| in a |std::set|. 55 BASE_EXPORT bool operator<(Entry lhs, Entry rhs); 56 57 // Serializes entries to an "entries" array in a traced value. 58 BASE_EXPORT std::unique_ptr<TracedValue> Serialize(const std::set<Entry>& dump); 59 60 // Helper class to dump a snapshot of an |AllocationRegister| or other heap 61 // bookkeeping structure into a |TracedValue|. This class is intended to be 62 // used as a one-shot local instance on the stack. 63 class BASE_EXPORT HeapDumpWriter { 64 public: 65 // The |stack_frame_deduplicator| and |type_name_deduplicator| are not owned. 66 // The heap dump writer assumes exclusive access to them during the lifetime 67 // of the dump writer. The heap dumps are broken down for allocations bigger 68 // than |breakdown_threshold_bytes|. 69 HeapDumpWriter(StackFrameDeduplicator* stack_frame_deduplicator, 70 TypeNameDeduplicator* type_name_deduplicator, 71 uint32_t breakdown_threshold_bytes); 72 73 ~HeapDumpWriter(); 74 75 // Aggregates allocations to compute the total size of the heap, then breaks 76 // down the heap recursively. This produces the values that should be dumped 77 // in the "entries" array. The number of entries is kept reasonable because 78 // long tails are not included. Use |Serialize| to convert to a traced value. 79 const std::set<Entry>& Summarize( 80 const hash_map<AllocationContext, AllocationMetrics>& metrics_by_context); 81 82 private: 83 // Inserts an |Entry| for |Bucket| into |entries_|. Returns false if the 84 // entry was present before, true if it was not. 85 bool AddEntryForBucket(const Bucket& bucket); 86 87 // Recursively breaks down a bucket into smaller buckets and adds entries for 88 // the buckets worth dumping to |entries_|. 89 void BreakDown(const Bucket& bucket); 90 91 // The collection of entries that is filled by |Summarize|. 92 std::set<Entry> entries_; 93 94 // Helper for generating the |stackFrames| dictionary. Not owned, must outlive 95 // this heap dump writer instance. 96 StackFrameDeduplicator* const stack_frame_deduplicator_; 97 98 // Helper for converting type names to IDs. Not owned, must outlive this heap 99 // dump writer instance. 100 TypeNameDeduplicator* const type_name_deduplicator_; 101 102 // Minimum size of an allocation for which an allocation bucket will be 103 // broken down with children. 104 uint32_t breakdown_threshold_bytes_; 105 106 DISALLOW_COPY_AND_ASSIGN(HeapDumpWriter); 107 }; 108 109 } // namespace internal 110 } // namespace trace_event 111 } // namespace base 112 113 #endif // BASE_TRACE_EVENT_HEAP_PROFILER_HEAP_DUMP_WRITER_H_ 114