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Relaxed tail loads in Ringbuffer #16

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Merged
raphael-s-steiner merged 1 commit into from
Apr 7, 2026
Merged

Relaxed tail loads in Ringbuffer #16

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10 changes: 5 additions & 5 deletions include/RingBuffer/RingBuffer.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -141,7 +141,7 @@ inline bool RingBuffer<T, N>::empty() const noexcept {
*/
template <typename T, std::size_t N>
inline bool RingBuffer<T, N>::full() const noexcept {
return tailCounter_.load(std::memory_order_acquire) + N == headCounter_.load(std::memory_order_relaxed);
return tailCounter_.load(std::memory_order_relaxed) + N == headCounter_.load(std::memory_order_relaxed);
};

/**
Expand All @@ -151,7 +151,7 @@ inline bool RingBuffer<T, N>::full() const noexcept {
*/
template <typename T, std::size_t N>
inline std::size_t RingBuffer<T, N>::occupancy() const noexcept {
return headCounter_.load(std::memory_order_acquire) - tailCounter_.load(std::memory_order_acquire);
return headCounter_.load(std::memory_order_acquire) - tailCounter_.load(std::memory_order_relaxed);
};

template <typename T, std::size_t N>
Expand Down Expand Up @@ -187,7 +187,7 @@ inline bool RingBuffer<T, N>::push(const T value) noexcept {
const std::size_t headLoopAround = head - N;
const bool nonFull
= (cachedTailCounter_ != headLoopAround)
|| ((cachedTailCounter_ = tailCounter_.load(std::memory_order_acquire)) != headLoopAround);
|| ((cachedTailCounter_ = tailCounter_.load(std::memory_order_relaxed)) != headLoopAround);
if (nonFull) {
data_[head % N] = value;
updateHead(head + 1U);
Expand All @@ -205,12 +205,12 @@ inline bool RingBuffer<T, N>::push(InputIt first, InputIt last) noexcept {
if constexpr ((sizeof(std::size_t) >= 8) && (N <= ((std::numeric_limits<std::size_t>::max() / 2) + 1U))) {
const std::size_t diff = head - N + numElements;
enoughSpace = (cachedTailCounter_ >= diff)
|| ((cachedTailCounter_ = tailCounter_.load(std::memory_order_acquire)) >= diff);
|| ((cachedTailCounter_ = tailCounter_.load(std::memory_order_relaxed)) >= diff);
} else {
const std::size_t diff = N - numElements;
enoughSpace
= ((head - cachedTailCounter_ <= diff)
|| ((head - (cachedTailCounter_ = tailCounter_.load(std::memory_order_acquire))) <= diff));
|| ((head - (cachedTailCounter_ = tailCounter_.load(std::memory_order_relaxed))) <= diff));
}

if (enoughSpace) {
Expand Down