Apple Inc.
Hybrid Memory in a Dynamically Power Gated Hardware Accelerator

Abstract:

In an embodiment, a local memory dedicated to one or more hardware accelerators in a system may include at least two portions: a volatile portion and a non-volatile portion. Data that is reused from iteration to iteration of the hardware accelerator (e.g. constants, instruction words, etc.) may be stored in the non-volatile portion. Data that varies from iteration to iteration may be stored in the volatile portion. Both the local memory and the hardware accelerators may be powered down between iterations, saving power. The non-volatile portion need only be initialized at a first iteration, allowing the amount of time that the hardware accelerators and the local memory are powered up to be lessened for subsequent iterations since the reused data need not be reloaded in the subsequent iterations.