[trws]

I can see how you got here from the release notes, but the conclusions are a bit off. For hardware and kernels that support the full HMM setup with AMD, you get 3 today as long as XNACK is turned on. Systems like Frontier have been using it for some time now.

Also, 2 can be subdivided into systems that implement it by having two allocations, one host one device, and triggering transfers when the GPU might access memory (2.1) and those that implement demand paging (2.2). The HMM support adds demand paging for type 2.2 as well as type 3 on supported hardware, where without it hip had to use either 2.1 or remote PCIE access to provide “unified memory”. Those were dark days, but for current hardware on appropriate kernels appropriately configured, AMD implements memory just as unified as either NVIDIA’s HMM or ATS implementations.