Accelerator virtualization

Abstract

Welcome to this special issue on accelerator virtualization in Concurrency and Computation: Practice and Experience. Virtualization is a key technique developed for sharing the underlying physical resources of a computer, such as the processor or memory and the network. This enables effective use of resources by improving their utilization and reduces costs. A well-known example of virtualization are virtual machines that have become prominent with the advent of cloud technologies. Virtual machines are an abstraction of the underlying physical computer that can be made available to different users. The underpinning technology ensures data security by isolating the environment in which each user works. Creating and executing virtual machines requires both software and hardware support. It is thought that one of the earliest forms of virtualization was time-multiplexing a single processor for different applications. Although this significantly varies from the current notion of virtualization, processor multiplexing laid the groundwork for modern operating systems to facilitate the concurrent sharing of an expensive hardware resource among several applications as if they each used the resource exclusively. A network file system is another example of virtualization in which the file system is physically available to several nodes of a computer cluster while it is simultaneously accessed by different client nodes. In this case, storage is the common resource shared via multiplexing mechanisms. Recently, virtualization has been adopted for hardware accelerators, specialized hardware such as graphics processing units (GPUs), field programmable gate arrays (FPGAs), and tensor processing units (TPUs). Accelerators reduce the execution time of certain applications by allowing programmers to offload compute intensive components of their applications to accelerators. They are also known to improve energy efficiency. We hope that the contents of this special issue are useful to you and that you enjoy them as much as we did.