Generalizing the SPUFS concept - a case study towards a common accelerator interface

The development of specialized application accel- erators is happening today. However, they do not share a common attach point, and have no common architecture or programing model. A framework that economically and efficiently enables specialized acceleration is highly desirable. In this work we propose a generic interface con- cept called "ACCFS" for integrating application accelerators into Linux-based platforms. The idea is to extend the programing model chosen by the Linux for Cell/B.E. team. On the Cell/B.E. multiple indepen- dent vector processors called Synergistic Processing Units (SPUs) are built around a 64-bit PowerPC core (PPE). The programing model is to create a virtual file system (VFS) to export the functionality of the SPUs to the user space via a file interface, they called it "SPUFS". Against other solutions such as using character devices or introducing a new process space the VFS interface uses common file system calls and provides an economic and efficient access to the accelerator units, the SPUs. Together with this concept and the experiences from an intermediate step called "RSPUFS" we introduce the first approaches towards a common accelerator file system (ACCFS).