TAP - Token-Based Adaptive Power Gating

We propose a low-overhead technique, Token-Based Adaptive Power Gating (TAP), to power gate an actively executing out-of-order core during memory accesses. TAP tracks every system memory request, providing a lower-bound estimate for the response time. TAP also tracks the state of every power-gateable core in the system, to provide minimal latency wake-up modes to cores such that voltage noise safety margins are not violated. A power-gating switch that utilizes TAP can deterministically power gate its core with energy savings up to 22.39% and no performance hit