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Fixed issue #546 by adding an "is_empty" method to the queue instead of the buggy approx_size

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This commit is contained in:
gabime
2017-11-05 00:21:00 +02:00
parent 6fd5f3c866
commit f5fe681a41
2 changed files with 102 additions and 106 deletions
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2
include/spdlog/details/async_log_helper.h
View File

@@ -384,7 +384,7 @@ inline void spdlog::details::async_log_helper::sleep_or_yield(const spdlog::log_
inline void spdlog::details::async_log_helper::wait_empty_q()
{
auto last_op = details::os::now();
while (_q.approx_size() > 0)
while (!_q.is_empty())
{
sleep_or_yield(details::os::now(), last_op);
}

206
include/spdlog/details/mpmc_bounded_q.h
View File

@@ -50,123 +50,119 @@ Distributed under the MIT License (http://opensource.org/licenses/MIT)
namespace spdlog
{
namespace details
{
namespace details
{
template<typename T>
class mpmc_bounded_queue
{
public:
template<typename T>
class mpmc_bounded_queue
{
public:
using item_type = T;
mpmc_bounded_queue(size_t buffer_size)
:max_size_(buffer_size),
buffer_(new cell_t [buffer_size]),
buffer_mask_(buffer_size - 1)
{
//queue size must be power of two
if(!((buffer_size >= 2) && ((buffer_size & (buffer_size - 1)) == 0)))
throw spdlog_ex("async logger queue size must be power of two");
using item_type = T;
mpmc_bounded_queue(size_t buffer_size)
:max_size_(buffer_size),
buffer_(new cell_t[buffer_size]),
buffer_mask_(buffer_size - 1)
{
//queue size must be power of two
if (!((buffer_size >= 2) && ((buffer_size & (buffer_size - 1)) == 0)))
throw spdlog_ex("async logger queue size must be power of two");
for (size_t i = 0; i != buffer_size; i += 1)
buffer_[i].sequence_.store(i, std::memory_order_relaxed);
enqueue_pos_.store(0, std::memory_order_relaxed);
dequeue_pos_.store(0, std::memory_order_relaxed);
}
for (size_t i = 0; i != buffer_size; i += 1)
buffer_[i].sequence_.store(i, std::memory_order_relaxed);
enqueue_pos_.store(0, std::memory_order_relaxed);
dequeue_pos_.store(0, std::memory_order_relaxed);
}
~mpmc_bounded_queue()
{
delete [] buffer_;
}
~mpmc_bounded_queue()
{
delete[] buffer_;
}
bool enqueue(T&& data)
{
cell_t* cell;
size_t pos = enqueue_pos_.load(std::memory_order_relaxed);
for (;;)
{
cell = &buffer_[pos & buffer_mask_];
size_t seq = cell->sequence_.load(std::memory_order_acquire);
intptr_t dif = static_cast<intptr_t>(seq) - static_cast<intptr_t>(pos);
if (dif == 0)
{
if (enqueue_pos_.compare_exchange_weak(pos, pos + 1, std::memory_order_relaxed))
break;
}
else if (dif < 0)
{
return false;
}
else
{
pos = enqueue_pos_.load(std::memory_order_relaxed);
}
}
cell->data_ = std::move(data);
cell->sequence_.store(pos + 1, std::memory_order_release);
return true;
}
bool enqueue(T&& data)
{
cell_t* cell;
size_t pos = enqueue_pos_.load(std::memory_order_relaxed);
for (;;) {
cell = &buffer_[pos & buffer_mask_];
size_t seq = cell->sequence_.load(std::memory_order_acquire);
intptr_t dif = static_cast<intptr_t>(seq) - static_cast<intptr_t>(pos);
if (dif == 0) {
if (enqueue_pos_.compare_exchange_weak(pos, pos + 1, std::memory_order_relaxed))
break;
}
else if (dif < 0) {
return false;
}
else {
pos = enqueue_pos_.load(std::memory_order_relaxed);
}
}
cell->data_ = std::move(data);
cell->sequence_.store(pos + 1, std::memory_order_release);
return true;
}
bool dequeue(T& data)
{
cell_t* cell;
size_t pos = dequeue_pos_.load(std::memory_order_relaxed);
for (;;)
{
cell = &buffer_[pos & buffer_mask_];
size_t seq =
cell->sequence_.load(std::memory_order_acquire);
intptr_t dif = static_cast<intptr_t>(seq) - static_cast<intptr_t>(pos + 1);
if (dif == 0)
{
if (dequeue_pos_.compare_exchange_weak(pos, pos + 1, std::memory_order_relaxed))
break;
}
else if (dif < 0)
return false;
else
pos = dequeue_pos_.load(std::memory_order_relaxed);
}
data = std::move(cell->data_);
cell->sequence_.store(pos + buffer_mask_ + 1, std::memory_order_release);
return true;
}
bool dequeue(T& data)
{
cell_t* cell;
size_t pos = dequeue_pos_.load(std::memory_order_relaxed);
for (;;) {
cell = &buffer_[pos & buffer_mask_];
size_t seq =
cell->sequence_.load(std::memory_order_acquire);
intptr_t dif = static_cast<intptr_t>(seq) - static_cast<intptr_t>(pos + 1);
if (dif == 0) {
if (dequeue_pos_.compare_exchange_weak(pos, pos + 1, std::memory_order_relaxed))
break;
}
else if (dif < 0)
return false;
else
pos = dequeue_pos_.load(std::memory_order_relaxed);
}
data = std::move(cell->data_);
cell->sequence_.store(pos + buffer_mask_ + 1, std::memory_order_release);
return true;
}
size_t approx_size()
{
size_t first_pos = dequeue_pos_.load(std::memory_order_relaxed);
size_t last_pos = enqueue_pos_.load(std::memory_order_relaxed);
if (last_pos <= first_pos)
return 0;
auto size = last_pos - first_pos;
return size < max_size_ ? size : max_size_;
}
bool is_empty()
{
unsigned front, front1, back;
// try to take a consistent snapshot of front/tail.
do {
front = enqueue_pos_.load(std::memory_order_acquire);
back = dequeue_pos_.load(std::memory_order_acquire);
front1 = enqueue_pos_.load(std::memory_order_relaxed);
} while (front != front1);
return back == front;
}
private:
struct cell_t
{
std::atomic<size_t> sequence_;
T data_;
};
private:
struct cell_t
{
std::atomic<size_t> sequence_;
T data_;
};
size_t const max_size_;
size_t const max_size_;
static size_t const cacheline_size = 64;
typedef char cacheline_pad_t [cacheline_size];
static size_t const cacheline_size = 64;
typedef char cacheline_pad_t[cacheline_size];
cacheline_pad_t pad0_;
cell_t* const buffer_;
size_t const buffer_mask_;
cacheline_pad_t pad1_;
std::atomic<size_t> enqueue_pos_;
cacheline_pad_t pad2_;
std::atomic<size_t> dequeue_pos_;
cacheline_pad_t pad3_;
cacheline_pad_t pad0_;
cell_t* const buffer_;
size_t const buffer_mask_;
cacheline_pad_t pad1_;
std::atomic<size_t> enqueue_pos_;
cacheline_pad_t pad2_;
std::atomic<size_t> dequeue_pos_;
cacheline_pad_t pad3_;
mpmc_bounded_queue(mpmc_bounded_queue const&) = delete;
void operator= (mpmc_bounded_queue const&) = delete;
};
mpmc_bounded_queue(mpmc_bounded_queue const&) = delete;
void operator= (mpmc_bounded_queue const&) = delete;
};
} // ns details
} // ns details
} // ns spdlog