Embodiments relate to a heterogeneous core microarchitecture. An aspect includes binding, by an operating system that is executing on a processor comprising a core comprising a heterogeneous microarchitecture comprising two or more flows, a job that is being executed by the operating system to a flow of the two or more flows. Another aspect includes issuing an instruction corresponding to the job with a tag indicating the binding of the job to which the instruction corresponds. Yet another aspect includes executing the instruction by the flow in the core that is indicated by the tag.