feat(ringbuffer): add compatibility layer for hardware interference size

src/linyaps_box/utils/ringbuffer.cpp

@@ -16,7 +16,7 @@ auto ring_buffer_deleter::operator()(ring_buffer *rb) const -> void
     rb->~ring_buffer();
     ::operator delete(rb,
                       total_size,
-                      std::align_val_t(std::hardware_constructive_interference_size));
+                      std::align_val_t(compat::hardware_constructive_interference_size));
 }
 
 auto ring_buffer::create(std::size_t requested_capacity)
@@ -31,7 +31,7 @@ auto ring_buffer::create(std::size_t requested_capacity)
 
     const auto total_size = sizeof(ring_buffer) + capacity;
     auto *mem = ::operator new(total_size,
-                               std::align_val_t(std::hardware_constructive_interference_size));
+                               std::align_val_t(compat::hardware_constructive_interference_size));
     auto *rb = new (mem) ring_buffer(capacity);
     return { rb, ring_buffer_deleter(total_size) };
 }

src/linyaps_box/utils/ringbuffer.h

@@ -12,6 +12,18 @@
 #include <sys/uio.h>
 #include <unistd.h>
 
+namespace linyaps_box::compat {
+#ifdef __cpp_lib_hardware_interference_size
+using std::hardware_constructive_interference_size;
+using std::hardware_destructive_interference_size;
+#else
+// default to 64 bytes if not defined
+// if the platform has different cache line size, please define these macros accordingly
+constexpr std::size_t hardware_constructive_interference_size = 64;
+constexpr std::size_t hardware_destructive_interference_size = 64;
+#endif
+} // namespace linyaps_box::compat
+
 namespace linyaps_box::utils {
 
 class ring_buffer;
@@ -26,7 +38,7 @@ struct ring_buffer_deleter
     std::size_t total_size{ 0 };
 };
 
-class alignas(std::hardware_constructive_interference_size) ring_buffer
+class alignas(compat::hardware_constructive_interference_size) ring_buffer
 {
     using iov_view = std::array<struct iovec, 2>;