Isn't this just a subset of the existing capacity monitoring problem where I want to know how loaded a multi-core system is under the following scenario:
Some critical path, single-threaded task is at 100% of capacity of a core; the system has 10 cores -- is my system at 10% utilization or 100% utilization?
Well, I certainly track capacity by power used by servers under management, but a system that's pinned on one thread is at 100% utilization, for very real definitions of "capacity" but the power consumed will also be some small fraction of how much power would be drawn if you were lighting up all the cores at 100% also.
Some critical path, single-threaded task is at 100% of capacity of a core; the system has 10 cores -- is my system at 10% utilization or 100% utilization?