I'm not sure how cache coherency would help here. Cache coherency is specifically about keeping cache coherent (i.e. not stale) in shared memory systems. It is

I'm not sure how cache coherency would help here. Cache coherency is specifically about keeping cache coherent (i.e. not stale) in shared memory systems. It is not applicable to pure message passing systems. Also cache coherency per se it has little to say about sequencing and happens-before. That's the job of the memory model built on top (again, still for shared memory). At an higher level still, the general idea of consistency is of course applicable to both shared memory concurrency and message passing concurrency. Maybe consistency models is what you are thinking about? Alternatively, maybe you want to implement shared-memory on top of message passing. In this case cache coherency is definitely applicable, but I'm not sure how amenable are common cache coherency protocols to be implemented in software (but it is certainly possible, and probably what some RDMA system do).