CCF_100
/
yuzu-mirror
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

Merge pull request #1352 from lioncash/sharing 

ring_buffer: Use std::hardware_destructive_interference_size to determine alignment size for avoiding false sharing
master
bunnei 2018-09-20 23:29:10 +07:00 committed by GitHub
parent 9f92533cc2 ab6dfa4fa5
commit a0db7e2cf9
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 11 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

14
src/common/ring_buffer.h
Unescape Escape View File

@ -9,6 +9,7 @@
#include <atomic>
#include <cstddef>
#include <cstring>
#include <new>
#include <type_traits>
#include <vector>
#include "common/common_types.h"
@ -29,7 +30,7 @@ class RingBuffer {
static_assert(capacity < std::numeric_limits<std::size_t>::max() / 2 / granularity);
static_assert((capacity & (capacity - 1)) == 0, "capacity must be a power of two");
// Ensure lock-free.
static_assert(std::atomic<std::size_t>::is_always_lock_free);
static_assert(std::atomic_size_t::is_always_lock_free);
public:
/// Pushes slots into the ring buffer
@ -102,8 +103,15 @@ public:
private:
// It is important to align the below variables for performance reasons:
// Having them on the same cache-line would result in false-sharing between them.
alignas(128) std::atomic<std::size_t> m_read_index{0};
alignas(128) std::atomic<std::size_t> m_write_index{0};
// TODO: Remove this ifdef whenever clang and GCC support
// std::hardware_destructive_interference_size.
#if defined(_MSC_VER) && _MSC_VER >= 1911
alignas(std::hardware_destructive_interference_size) std::atomic_size_t m_read_index{0};
alignas(std::hardware_destructive_interference_size) std::atomic_size_t m_write_index{0};
#else
alignas(128) std::atomic_size_t m_read_index{0};
alignas(128) std::atomic_size_t m_write_index{0};
#endif
std::array<T, granularity * capacity> m_data;
};