// Copyright 2021 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 INCLUDE_CPPGC_HEAP_STATISTICS_H_
#define INCLUDE_CPPGC_HEAP_STATISTICS_H_
#include <cstddef>
#include <cstdint>
#include <string>
#include <vector>
namespace cppgc {
/**
* `HeapStatistics` contains memory consumption and utilization statistics for a
* cppgc heap.
*/
struct HeapStatistics final {
/**
* Specifies the detail level of the heap statistics. Brief statistics contain
* only the top-level allocated and used memory statistics for the entire
* heap. Detailed statistics also contain a break down per space and page, as
* well as freelist statistics and object type histograms. Note that used
* memory reported by brief statistics and detailed statistics might differ
* slightly.
*/
enum DetailLevel : uint8_t {
kBrief,
kDetailed,
};
/**
* Object statistics for a single type.
*/
struct ObjectStatsEntry {
/**
* Number of allocated bytes.
*/
size_t allocated_bytes;
/**
* Number of allocated objects.
*/
size_t object_count;
};
/**
* Page granularity statistics. For each page the statistics record the
* allocated memory size and overall used memory size for the page.
*/
struct PageStatistics {
/** Overall committed amount of memory for the page. */
size_t committed_size_bytes = 0;
/** Resident amount of memory held by the page. */
size_t resident_size_bytes = 0;
/** Amount of memory actually used on the page. */
size_t used_size_bytes = 0;
/** Statistics for object allocated on the page. Filled only when
* NameProvider::SupportsCppClassNamesAsObjectNames() is true. */
std::vector<ObjectStatsEntry> object_statistics;
};
/**
* Statistics of the freelist (used only in non-large object spaces). For
* each bucket in the freelist the statistics record the bucket size, the
* number of freelist entries in the bucket, and the overall allocated memory
* consumed by these freelist entries.
*/
struct FreeListStatistics {
/** bucket sizes in the freelist. */
std::vector<size_t> bucket_size;
/** number of freelist entries per bucket. */
std::vector<size_t> free_count;
/** memory size consumed by freelist entries per size. */
std::vector<size_t> free_size;
};
/**
* Space granularity statistics. For each space the statistics record the
* space name, the amount of allocated memory and overall used memory for the
* space. The statistics also contain statistics for each of the space's
* pages, its freelist and the objects allocated on the space.
*/
struct SpaceStatistics {
/** The space name */
std::string name;
/** Overall committed amount of memory for the heap. */
size_t committed_size_bytes = 0;
/** Resident amount of memory held by the heap. */
size_t resident_size_bytes = 0;
/** Amount of memory actually used on the space. */
size_t used_size_bytes = 0;
/** Statistics for each of the pages in the space. */
std::vector<PageStatistics> page_stats;
/** Statistics for the freelist of the space. */
FreeListStatistics free_list_stats;
};
/** Overall committed amount of memory for the heap. */
size_t committed_size_bytes = 0;
/** Resident amount of memory held by the heap. */
size_t resident_size_bytes = 0;
/** Amount of memory actually used on the heap. */
size_t used_size_bytes = 0;
/** Detail level of this HeapStatistics. */
DetailLevel detail_level;
/** Statistics for each of the spaces in the heap. Filled only when
* `detail_level` is `DetailLevel::kDetailed`. */
std::vector<SpaceStatistics> space_stats;
/**
* Vector of `cppgc::GarbageCollected` type names.
*/
std::vector<std::string> type_names;
};
} // namespace cppgc
#endif // INCLUDE_CPPGC_HEAP_STATISTICS_H_
