Align struct to cache lines in Rust

Question

Assuming I wanted to (ab)use cache coherency to do lock free reads like FaRM, would it be enough to have a struct with a single 64 byte array as data to guarantee that on an architecture with 64 byte cache lines each struct would occupy exactly one cache line?

Answer 1

No, that wouldn't guarantee that the alignment was a cache line.

RFC 1358 added the concept of #[repr(align)], allowing the programmer to specify alignment requirements. This attribute was stabilized in Rust 1.25.

For your specific case, you'd use it like:

#[repr(align(64))]
struct Foo {
    value: u8,
}