Virtual direct memory access (dma) channel technique with multiple engines for dma controller

Abstract

A virtual DMA channel technique in which a generally larger number of DMA channels are mapped to a generally smaller number of DMA engines can provide a configuration in which switches amongst DMA engines (and therefore amongst a current working set of DMA channels currently mapped thereto) can be accomplished without context switch latency. Accordingly, as long as contents of the current working set can be appropriately managed, many changes (whether or nor priority based) between a current active DMA channel and a next runnable DMA channel can be accomplished without incurring a context switch latency such as normally associated with loading/restoring and/or saving DMA context information. In some embodiments, a working set or replacement strategy that seeks to cache a most frequently (or most recently) used subset of virtual DMA channels is employed. In some embodiments, a set- or frame-oriented variants of such strategies may be employed.