base/trace_event/trace_event_memory_overhead.cc

// Copyright 2015 The Chromium 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 "base/trace_event/trace_event_memory_overhead.h"

#include <algorithm>

#include "base/bits.h"
#include "base/memory/ref_counted_memory.h"
#include "base/strings/stringprintf.h"
#include "base/trace_event/memory_allocator_dump.h"
#include "base/trace_event/process_memory_dump.h"
#include "base/values.h"

namespace base {
namespace trace_event {

TraceEventMemoryOverhead::TraceEventMemoryOverhead() {
}

TraceEventMemoryOverhead::~TraceEventMemoryOverhead() {
}

void TraceEventMemoryOverhead::AddOrCreateInternal(
    const char* object_type,
    size_t count,
    size_t allocated_size_in_bytes,
    size_t resident_size_in_bytes) {
  auto it = allocated_objects_.find(object_type);
  if (it == allocated_objects_.end()) {
    allocated_objects_.insert(std::make_pair(
        object_type,
        ObjectCountAndSize(
            {count, allocated_size_in_bytes, resident_size_in_bytes})));
    return;
  }
  it->second.count += count;
  it->second.allocated_size_in_bytes += allocated_size_in_bytes;
  it->second.resident_size_in_bytes += resident_size_in_bytes;
}

void TraceEventMemoryOverhead::Add(const char* object_type,
                                   size_t allocated_size_in_bytes) {
  Add(object_type, allocated_size_in_bytes, allocated_size_in_bytes);
}

void TraceEventMemoryOverhead::Add(const char* object_type,
                                   size_t allocated_size_in_bytes,
                                   size_t resident_size_in_bytes) {
  AddOrCreateInternal(object_type, 1, allocated_size_in_bytes,
                      resident_size_in_bytes);
}

void TraceEventMemoryOverhead::AddString(const std::string& str) {
  // The number below are empirical and mainly based on profiling of real-world
  // std::string implementations:
  //  - even short string end up malloc()-inc at least 32 bytes.
  //  - longer strings seem to malloc() multiples of 16 bytes.
  const size_t capacity = bits::Align(str.capacity(), 16);
  Add("std::string", sizeof(std::string) + std::max<size_t>(capacity, 32u));
}

void TraceEventMemoryOverhead::AddRefCountedString(
    const RefCountedString& str) {
  Add("RefCountedString", sizeof(RefCountedString));
  AddString(str.data());
}

void TraceEventMemoryOverhead::AddValue(const Value& value) {
  switch (value.GetType()) {
    case Value::Type::NONE:
    case Value::Type::BOOLEAN:
    case Value::Type::INTEGER:
    case Value::Type::DOUBLE:
      Add("FundamentalValue", sizeof(Value));
      break;

    case Value::Type::STRING: {
      const Value* string_value = nullptr;
      value.GetAsString(&string_value);
      Add("StringValue", sizeof(Value));
      AddString(string_value->GetString());
    } break;

    case Value::Type::BINARY: {
      const Value* binary_value = nullptr;
      value.GetAsBinary(&binary_value);
      Add("BinaryValue", sizeof(Value) + binary_value->GetSize());
    } break;

    case Value::Type::DICTIONARY: {
      const DictionaryValue* dictionary_value = nullptr;
      value.GetAsDictionary(&dictionary_value);
      Add("DictionaryValue", sizeof(DictionaryValue));
      for (DictionaryValue::Iterator it(*dictionary_value); !it.IsAtEnd();
           it.Advance()) {
        AddString(it.key());
        AddValue(it.value());
      }
    } break;

    case Value::Type::LIST: {
      const ListValue* list_value = nullptr;
      value.GetAsList(&list_value);
      Add("ListValue", sizeof(ListValue));
      for (const auto& v : *list_value)
        AddValue(v);
    } break;

    default:
      NOTREACHED();
  }
}

void TraceEventMemoryOverhead::AddSelf() {
  size_t estimated_size = sizeof(*this);
  // If the SmallMap did overflow its static capacity, its elements will be
  // allocated on the heap and have to be accounted separately.
  if (allocated_objects_.UsingFullMap())
    estimated_size += sizeof(map_type::value_type) * allocated_objects_.size();
  Add("TraceEventMemoryOverhead", estimated_size);
}

size_t TraceEventMemoryOverhead::GetCount(const char* object_type) const {
  const auto& it = allocated_objects_.find(object_type);
  if (it == allocated_objects_.end())
    return 0u;
  return it->second.count;
}

void TraceEventMemoryOverhead::Update(const TraceEventMemoryOverhead& other) {
  for (const auto& it : other.allocated_objects_) {
    AddOrCreateInternal(it.first, it.second.count,
                        it.second.allocated_size_in_bytes,
                        it.second.resident_size_in_bytes);
  }
}

void TraceEventMemoryOverhead::DumpInto(const char* base_name,
                                        ProcessMemoryDump* pmd) const {
  for (const auto& it : allocated_objects_) {
    std::string dump_name = StringPrintf("%s/%s", base_name, it.first);
    MemoryAllocatorDump* mad = pmd->CreateAllocatorDump(dump_name);
    mad->AddScalar(MemoryAllocatorDump::kNameSize,
                   MemoryAllocatorDump::kUnitsBytes,
                   it.second.allocated_size_in_bytes);
    mad->AddScalar("resident_size", MemoryAllocatorDump::kUnitsBytes,
                   it.second.resident_size_in_bytes);
    mad->AddScalar(MemoryAllocatorDump::kNameObjectCount,
                   MemoryAllocatorDump::kUnitsObjects, it.second.count);
  }
}

}  // namespace trace_event
}  // namespace base