travis: Update xcode

Update to 10.2 (required for CTAD to work correctly)
This commit is contained in:
MerryMage 2020-04-07 20:49:46 +01:00
parent 8b7b6e9f74
commit f2499953c0
2 changed files with 18 additions and 5 deletions

View File

@ -32,7 +32,7 @@ matrix:
- os: osx
env: NAME="macos build"
sudo: false
osx_image: xcode10
osx_image: xcode10.2
install: "./.travis/macos/deps.sh"
script: "./.travis/macos/build.sh"
after_success: "./.travis/macos/upload.sh"

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
@ -100,10 +101,22 @@ public:
}
private:
// It is important to align the below variables for performance reasons:
// It is important to separate the below atomics 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
static constexpr std::size_t padding_size =
std::hardware_destructive_interference_size - sizeof(std::atomic_size_t);
#else
static constexpr std::size_t padding_size = 128 - sizeof(std::atomic_size_t);
#endif
std::atomic_size_t m_read_index{0};
char padding1[padding_size];
std::atomic_size_t m_write_index{0};
char padding2[padding_size];
std::array<T, granularity * capacity> m_data;
};