Apple Inc.
METHODS AND APPARATUS FOR REDUCED OVERHEAD DATA TRANSFER WITH A SHARED RING BUFFER

Abstract:

Methods and apparatus for reducing bus overhead with virtualized transfer rings. The Inter-Processor Communications (IPC) bus uses a ring buffer (e.g., a so-called Transfer Ring (TR)) to provide Direct Memory Access (DMA)-like memory access between processors. However, performing small transactions within the TR inefficiently uses bus overhead. A Virtualized Transfer Ring (VTR) is a null data structure that doesn't require any backing memory allocation. A processor servicing a VTR data transfer includes the data payload as part of an optional header/footer data structure within a completion ring (CR).