consume is trivial on alpha, it is the same as acquire (always needs a #LoadLoad). It is also the same as acquire (and relaxed) on x86 and SPARC (a plain load, #LoadLoad is always implied).

The only place where consume matters is on relaxed but not too relaxed architectures like ARM and POWER, where consume relies on the implicit #LoadLoad of controls and data dependencies.

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bonzini 12 hours ago | parent [-]

Also on alpha there's only store-store and full memory barriers. Acquire is very expensive.

	▲	gpderetta 6 hours ago \| parent [-]
		Indeed. On the other hand recently ARM has added explicit load acquires primitives which are relatively cheap, so converting a consume to an acquire is not a big loss (and Linus considered doing it for the kernel a while ago just to avoid having to think too hard about compiler optimizations).