It doesn't sound reasonable that we have per-ULP feature (DIM is per-ULP) to be configured globally. Especially given the fact that users can find themselves running different workloads with different requirements on the same system. Currently each ULP has some sort of tool to configure itself and I think that once ULP is converted to use DIM, it should have on/off knob in the tool used by their users.
Its not any different than socket options that can have a global sysctl knob that can be overridden by individual socket consumers.