Move control block back to FlatHashTable itself to avoid cache line sharing between control blocks of all big tables.

This commit is contained in:
levlam 2022-03-09 15:17:29 +03:00
parent 88ce431f39
commit 5cda813bd9
1 changed files with 49 additions and 57 deletions

View File

@ -11,7 +11,6 @@
#include "td/utils/Random.h"
#include <cstddef>
#include <cstdlib>
#include <functional>
#include <initializer_list>
#include <iterator>
@ -161,70 +160,37 @@ struct SetNode {
template <class NodeT, class HashT, class EqT>
class FlatHashTable {
struct FlatHashTableInner {
uint32 used_node_count_;
uint32 bucket_count_mask_;
uint32 bucket_count_;
uint32 begin_bucket_;
NodeT nodes_[1];
};
static constexpr size_t OFFSET = 4 * sizeof(uint32);
static constexpr uint32 INVALID_BUCKET = 0xFFFFFFFF;
static inline FlatHashTableInner *get_inner(NodeT *nodes) {
DCHECK(nodes != nullptr);
return reinterpret_cast<FlatHashTableInner *>(reinterpret_cast<char *>(nodes) - OFFSET);
}
static NodeT *allocate_nodes(uint32 size) {
void allocate_nodes(uint32 size) {
DCHECK(size >= 8);
DCHECK((size & (size - 1)) == 0);
CHECK(size <= min(static_cast<uint32>(1) << 29, static_cast<uint32>((0x7FFFFFFF - OFFSET) / sizeof(NodeT))));
auto inner = static_cast<FlatHashTableInner *>(std::malloc(OFFSET + sizeof(NodeT) * size));
NodeT *nodes = &inner->nodes_[0];
for (uint32 i = 0; i < size; i++) {
new (nodes + i) NodeT();
}
// inner->used_node_count_ = 0;
inner->bucket_count_mask_ = size - 1;
inner->bucket_count_ = size;
inner->begin_bucket_ = INVALID_BUCKET;
return nodes;
CHECK(size <= min(static_cast<uint32>(1) << 29, static_cast<uint32>(0x7FFFFFFF / sizeof(NodeT))));
nodes_ = new NodeT[size];
// used_node_count_ = 0;
bucket_count_mask_ = size - 1;
bucket_count_ = size;
begin_bucket_ = INVALID_BUCKET;
}
static void clear_nodes(NodeT *nodes) {
auto inner = get_inner(nodes);
auto size = inner->bucket_count_;
for (uint32 i = 0; i < size; i++) {
nodes[i].~NodeT();
}
std::free(inner);
}
inline FlatHashTableInner *get_inner() {
return get_inner(nodes_);
}
inline const FlatHashTableInner *get_inner() const {
DCHECK(nodes_ != nullptr);
return get_inner(const_cast<NodeT *>(nodes_));
delete[] nodes;
}
inline uint32 &used_node_count() {
return get_inner()->used_node_count_;
return used_node_count_;
}
inline uint32 get_used_node_count() const {
return get_inner()->used_node_count_;
return used_node_count_;
}
inline uint32 get_bucket_count_mask() const {
return get_inner()->bucket_count_mask_;
return bucket_count_mask_;
}
inline uint32 get_bucket_count() const {
return get_inner()->bucket_count_;
return bucket_count_;
}
public:
@ -351,21 +317,34 @@ class FlatHashTable {
used_node_count() = used_nodes;
}
FlatHashTable(FlatHashTable &&other) noexcept : nodes_(other.nodes_) {
other.nodes_ = nullptr;
FlatHashTable(FlatHashTable &&other) noexcept
: nodes_(other.nodes_)
, used_node_count_(other.used_node_count_)
, bucket_count_mask_(other.bucket_count_mask_)
, bucket_count_(other.bucket_count_)
, begin_bucket_(other.begin_bucket_) {
other.drop();
}
void operator=(FlatHashTable &&other) noexcept {
clear();
nodes_ = other.nodes_;
other.nodes_ = nullptr;
used_node_count_ = other.used_node_count_;
bucket_count_mask_ = other.bucket_count_mask_;
bucket_count_ = other.bucket_count_;
begin_bucket_ = other.begin_bucket_;
other.drop();
}
void swap(FlatHashTable &other) noexcept {
std::swap(nodes_, other.nodes_);
std::swap(used_node_count_, other.used_node_count_);
std::swap(bucket_count_mask_, other.bucket_count_mask_);
std::swap(bucket_count_, other.bucket_count_);
std::swap(begin_bucket_, other.begin_bucket_);
}
~FlatHashTable() = default;
uint32 bucket_count() const {
return unlikely(nodes_ == nullptr) ? 0 : get_bucket_count();
return get_bucket_count();
}
Iterator find(const KeyT &key) {
@ -390,18 +369,18 @@ class FlatHashTable {
}
size_t size() const {
return unlikely(nodes_ == nullptr) ? 0 : get_used_node_count();
return get_used_node_count();
}
bool empty() const {
return unlikely(nodes_ == nullptr) || get_used_node_count() == 0;
return get_used_node_count() == 0;
}
Iterator begin() {
if (empty()) {
return end();
}
auto &begin_bucket = get_inner()->begin_bucket_;
auto &begin_bucket = begin_bucket_;
if (begin_bucket == INVALID_BUCKET) {
begin_bucket = Random::fast_uint32() & get_bucket_count_mask();
while (nodes_[begin_bucket].empty()) {
@ -483,7 +462,7 @@ class FlatHashTable {
void clear() {
if (nodes_ != nullptr) {
clear_nodes(nodes_);
nodes_ = nullptr;
drop();
}
}
@ -530,6 +509,18 @@ class FlatHashTable {
private:
NodeT *nodes_ = nullptr;
uint32 used_node_count_ = 0;
uint32 bucket_count_mask_ = 0;
uint32 bucket_count_ = 0;
uint32 begin_bucket_ = 0;
void drop() {
nodes_ = nullptr;
used_node_count_ = 0;
bucket_count_mask_ = 0;
bucket_count_ = 0;
begin_bucket_ = 0;
}
void assign(const FlatHashTable &other) {
if (other.size() == 0) {
@ -581,7 +572,7 @@ class FlatHashTable {
void resize(uint32 new_size) {
if (unlikely(nodes_ == nullptr)) {
nodes_ = allocate_nodes(new_size);
allocate_nodes(new_size);
used_node_count() = 0;
return;
}
@ -589,7 +580,7 @@ class FlatHashTable {
auto old_nodes = nodes_;
uint32 old_size = get_used_node_count();
uint32 old_bucket_count = get_bucket_count();
nodes_ = allocate_nodes(new_size);
allocate_nodes(new_size);
used_node_count() = old_size;
auto old_nodes_end = old_nodes + old_bucket_count;
@ -647,12 +638,13 @@ class FlatHashTable {
}
inline void invalidate_iterators() {
get_inner()->begin_bucket_ = INVALID_BUCKET;
begin_bucket_ = INVALID_BUCKET;
}
};
template <class KeyT, class ValueT, class HashT = std::hash<KeyT>, class EqT = std::equal_to<KeyT>>
using FlatHashMapImpl = FlatHashTable<MapNode<KeyT, ValueT>, HashT, EqT>;
template <class KeyT, class HashT = std::hash<KeyT>, class EqT = std::equal_to<KeyT>>
using FlatHashSetImpl = FlatHashTable<SetNode<KeyT>, HashT, EqT>;