containers_memory_benchmark.cc | Explore in Territory

// Copyright 2023 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
//
// This is a framework to measure the memory overhead of different containers.
// Under the hood, it works by logging allocations and frees using an allocator
// hook.
//
// Since the free callback does not report a size, and the allocator hooks run
// in the middle of allocation, the logger simply takes the simplest approach
// and logs out the raw data, relying on analyze_containers_memory_usage.py to
// turn the raw output into useful numbers.
//
// The output of consists of m (number of different key/value combinations being
// tested) x n (number of different map types being tested) sections:
//
// <key type 1> -> <value type 1>
// ===== <map type 1> =====
// iteration 0
// alloc <address 1> size <size 1>
// iteration 1
// alloc <address 2> size <size 2>
// free <address 1>
// iteration 2
// alloc <address 3> size <size 3>
// free <address 2>
// ...
// ...
// ...
// ===== <map type n>
// iteration 0
// alloc <address 1000> size <size 1000>
// iteration 1
// alloc <address 1001> size <size 1001>
// free <address 1000>
// iteration 2
// alloc <address 1002> size <size 1002>
// free <address 1001>
// ...
// ...
// ...
// <key type m> -> <value type m>
// ===== <map type 1> =====
// ...
// ...
// ===== <map type n> =====
//
// Alternate output strategies are possible, but most of them are worse/more
// complex, and do not eliminate the postprocessing step.

#include <array>
#include <atomic>
#include <charconv>
#include <limits>
#include <map>
#include <optional>
#include <string>
#include <unordered_map>
#include <utility>

#include "base/allocator/dispatcher/dispatcher.h"
#include "base/allocator/dispatcher/notification_data.h"
#include "base/containers/flat_map.h"
#include "base/logging.h"
#include "base/strings/safe_sprintf.h"
#include "base/unguessable_token.h"
#include "base/values.h"
#include "third_party/abseil-cpp/absl/container/btree_map.h"
#include "third_party/abseil-cpp/absl/container/flat_hash_map.h"
#include "third_party/abseil-cpp/absl/container/node_hash_map.h"

namespace {

std::atomic<bool> log_allocs_and_frees;

struct AllocationLogger { … };

class ScopedLogAllocAndFree { … };

// Measures the memory usage for a container with type `Container` from 0 to
// 6857 elements, using `inserter` to insert a single element at a time.
// `inserter` should be a functor that takes a `Container& container` as its
// first parameter and a `size_t current_index` as its second parameter.
//
// Note that `inserter` can't use `base::FunctionRef` since the inserter is
// passed through several layers before actually being instantiated below in
// this function.
template <typename Container, typename Inserter>
void MeasureOneContainer(const Inserter& inserter) { … }

// Measures the memory usage for all the container types under test. `inserter`
// is used to insert a single element at a time into the tested container.
template <typename K, typename V, typename Inserter>
void Measure(const Inserter& inserter) { … }

}  // namespace

int main() { … }
chromium/base/containers/containers_memory_benchmark.cc
