Managing Bytecode and ISA Compatibility with an Enhanced Toolchain

Abstract

We describe an approach to deploying only those bytecodes that can be executed by the current operating system and hardware resources in an environment that combines parallelism, processor heterogeneity and software-defined networking capabilities (SDN). Packet processing’s escalating speed requirements necessitate parallel processing and, typically, heterogeneous processing via specialized processors acting as accelerators. We use bytecodes for an abstract machine to drive the dissimilar processors with interpreters running in parallel. However, processors and SDN are evolving; thus, bytecodes must evolve as well. We must execute reliable programs for packet processing, so we need to deploy only bytecodes that the interpreters and system resources can support. Our solution combines: (a) correlating supported features, interpreter versions and hardware variants in a manifest file, (b) instrumenting a compiler to recognize key feature use, (c) carrying detected feature data in an object module section and (d) running a checking tool at pre-linking stages to prevent linking or deploying a bytecode that cannot be correctly executed. The scheme has handled deprecating features and adding a broad variety of new features. It has been stress-tested by significant changes in hardware variants.