Add ReaderWriterQueue and update ConcurrentQueue

This commit is contained in:
Paul Hollinsky
2020-03-09 13:38:14 -04:00
parent 9ac3fd56bd
commit 42780dc610
1629 changed files with 306008 additions and 868 deletions
@@ -0,0 +1,139 @@
#include "../../../atomicops.h"
#include <cstdlib> // For std::size_t
// From http://www.1024cores.net/home/lock-free-algorithms/queues/unbounded-spsc-queue
// (and http://software.intel.com/en-us/articles/single-producer-single-consumer-queue)
// load with 'consume' (data-dependent) memory ordering
template<typename T>
T load_consume(T const* addr)
{
// hardware fence is implicit on x86
T v = *const_cast<T const volatile*>(addr);
moodycamel::compiler_fence(moodycamel::memory_order_seq_cst);
return v;
}
// store with 'release' memory ordering
template<typename T>
void store_release(T* addr, T v)
{
// hardware fence is implicit on x86
moodycamel::compiler_fence(moodycamel::memory_order_seq_cst);
*const_cast<T volatile*>(addr) = v;
}
// cache line size on modern x86 processors (in bytes)
size_t const cache_line_size = 64;
// single-producer/single-consumer queue
template<typename T>
class spsc_queue
{
public:
spsc_queue()
{
node* n = new node;
n->next_ = 0;
tail_ = head_ = first_= tail_copy_ = n;
}
explicit spsc_queue(size_t prealloc)
{
node* n = new node;
n->next_ = 0;
tail_ = head_ = first_ = tail_copy_ = n;
// [CD] Not (at all) the most efficient way to pre-allocate memory, but it works
T dummy = T();
for (size_t i = 0; i != prealloc; ++i) {
enqueue(dummy);
}
for (size_t i = 0; i != prealloc; ++i) {
try_dequeue(dummy);
}
}
~spsc_queue()
{
node* n = first_;
do
{
node* next = n->next_;
delete n;
n = next;
}
while (n);
}
void enqueue(T v)
{
node* n = alloc_node();
n->next_ = 0;
n->value_ = v;
store_release(&head_->next_, n);
head_ = n;
}
// returns 'false' if queue is empty
bool try_dequeue(T& v)
{
if (load_consume(&tail_->next_))
{
v = tail_->next_->value_;
store_release(&tail_, tail_->next_);
return true;
}
else
{
return false;
}
}
private:
// internal node structure
struct node
{
node* next_;
T value_;
};
// consumer part
// accessed mainly by consumer, infrequently be producer
node* tail_; // tail of the queue
// delimiter between consumer part and producer part,
// so that they situated on different cache lines
char cache_line_pad_ [cache_line_size];
// producer part
// accessed only by producer
node* head_; // head of the queue
node* first_; // last unused node (tail of node cache)
node* tail_copy_; // helper (points somewhere between first_ and tail_)
node* alloc_node()
{
// first tries to allocate node from internal node cache,
// if attempt fails, allocates node via ::operator new()
if (first_ != tail_copy_)
{
node* n = first_;
first_ = first_->next_;
return n;
}
tail_copy_ = load_consume(&tail_);
if (first_ != tail_copy_)
{
node* n = first_;
first_ = first_->next_;
return n;
}
node* n = new node;
return n;
}
spsc_queue(spsc_queue const&);
spsc_queue& operator = (spsc_queue const&);
};
@@ -0,0 +1,174 @@
// Adapted from https://github.com/facebook/folly/blob/master/folly/ProducerConsumerQueue.h
/*
* Copyright 2013 Facebook, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
// @author Bo Hu (bhu@fb.com)
// @author Jordan DeLong (delong.j@fb.com)
#ifndef PRODUCER_CONSUMER_QUEUE_H_
#define PRODUCER_CONSUMER_QUEUE_H_
#include <new>
#include <atomic>
#include <cassert>
#include <cstdlib>
#include <stdexcept>
#include <type_traits>
#include <utility>
//#include <boost/noncopyable.hpp>
namespace folly {
/*
* ProducerConsumerQueue is a one producer and one consumer queue
* without locks.
*/
template<class T>
struct ProducerConsumerQueue {
typedef T value_type;
// size must be >= 1.
explicit ProducerConsumerQueue(uint32_t size)
: size_(size + 1) // +1 because one slot is always empty
, records_(static_cast<T*>(std::malloc(sizeof(T) * (size + 1))))
, readIndex_(0)
, writeIndex_(0)
{
assert(size >= 1);
if (!records_) {
throw std::bad_alloc();
}
}
~ProducerConsumerQueue() {
// We need to destruct anything that may still exist in our queue.
// (No real synchronization needed at destructor time: only one
// thread can be doing this.)
if (!std::is_trivially_destructible<T>::value) {
int read = readIndex_;
int end = writeIndex_;
while (read != end) {
records_[read].~T();
if (++read == size_) {
read = 0;
}
}
}
std::free(records_);
}
template<class ...Args>
bool enqueue(Args&&... recordArgs) {
auto const currentWrite = writeIndex_.load(std::memory_order_relaxed);
auto nextRecord = currentWrite + 1;
if (nextRecord == size_) {
nextRecord = 0;
}
if (nextRecord != readIndex_.load(std::memory_order_acquire)) {
new (&records_[currentWrite]) T(std::forward<Args>(recordArgs)...);
writeIndex_.store(nextRecord, std::memory_order_release);
return true;
}
// queue is full
return false;
}
// move (or copy) the value at the front of the queue to given variable
bool try_dequeue(T& record) {
auto const currentRead = readIndex_.load(std::memory_order_relaxed);
if (currentRead == writeIndex_.load(std::memory_order_acquire)) {
// queue is empty
return false;
}
auto nextRecord = currentRead + 1;
if (nextRecord == size_) {
nextRecord = 0;
}
record = std::move(records_[currentRead]);
records_[currentRead].~T();
readIndex_.store(nextRecord, std::memory_order_release);
return true;
}
// pointer to the value at the front of the queue (for use in-place) or
// nullptr if empty.
T* frontPtr() {
auto const currentRead = readIndex_.load(std::memory_order_relaxed);
if (currentRead == writeIndex_.load(std::memory_order_acquire)) {
// queue is empty
return nullptr;
}
return &records_[currentRead];
}
// queue must not be empty
void popFront() {
auto const currentRead = readIndex_.load(std::memory_order_relaxed);
assert(currentRead != writeIndex_.load(std::memory_order_acquire));
auto nextRecord = currentRead + 1;
if (nextRecord == size_) {
nextRecord = 0;
}
records_[currentRead].~T();
readIndex_.store(nextRecord, std::memory_order_release);
}
bool isEmpty() const {
return readIndex_.load(std::memory_order_consume) ==
writeIndex_.load(std::memory_order_consume);
}
bool isFull() const {
auto nextRecord = writeIndex_.load(std::memory_order_consume) + 1;
if (nextRecord == size_) {
nextRecord = 0;
}
if (nextRecord != readIndex_.load(std::memory_order_consume)) {
return false;
}
// queue is full
return true;
}
// * If called by consumer, then true size may be more (because producer may
// be adding items concurrently).
// * If called by producer, then true size may be less (because consumer may
// be removing items concurrently).
// * It is undefined to call this from any other thread.
size_t sizeGuess() const {
int ret = writeIndex_.load(std::memory_order_consume) -
readIndex_.load(std::memory_order_consume);
if (ret < 0) {
ret += size_;
}
return ret;
}
private:
const uint32_t size_;
T* const records_;
std::atomic<int> readIndex_;
std::atomic<int> writeIndex_;
};
}
#endif