You really want those "efficiency" cores in addition to your regular ones, otherwise dividing your processor costs you a lot of throughput. You also want them

You really want those "efficiency" cores in addition to your regular ones, otherwise dividing your processor costs you a lot of throughput. You also want them to be low-power even when saturated, otherwise you gain responsiveness from the "performance" cores but your "efficiency" cores aren't actually efficient. It seems at least Linux's x86_energy_perf_policy tool lets you set multiplier ranges and some performance-vs-power values per-core, which means such a setup doesn't seem impossible on current Intel hardware.