When a machine is large enough with enough tenants, there should be enough ambient junk going on to poll on 1 or a few cores and still be optimized for power. T

When a machine is large enough with enough tenants, there should be enough ambient junk going on to poll on 1 or a few cores and still be optimized for power. This is the tradeoff described in the 2019 "SNAP" paper from Google, in the section about the compacting engine. The "up to 30%" figure is operative when you have a near-idle application that's busy polling, which is already dumb. There are several ways to save energy in that case.