Research Initiation Award: Incorporating Fault Tolerance in the Multiscalar Processor

多标量处理器是最近提出的一种利用指令级并行性的执行范例。它是一个顺序处理器的集合，这些处理器使用环形网络以逻辑上解耦和物理上分散的方式连接在一起。其核心思想是将指令流划分为指令块，然后通过使用多个处理元素执行这些块来利用并行性。多标量处理器在学术界和工业界都引起了广泛的兴趣，并且似乎有巨大的潜力成为2000年左右的入门级并行处理器的首选处理范例。本研究的目的是开发一种高性能的容错多标量处理器，并为在通用处理器中加入容错提供动力。多标量处理器中容错的主要方式是通过软件的运行时复制和在处理器的多个执行单元上执行副本，这是出于性能原因而提供的。正在研究两种重新执行方案（都使用相同的复制技术）。为了了解由于容错导致的性能损失，进行了初步的仿真研究。这些初步结果表明，时间冗余技术是在多标量处理器中提供容错的一个很好的选择。＊＊＊

9410706 Franklin The multiscalar processor is a recently proposed execution paradigm for exploiting instruction-level parallelism. It is a collection of sequential processors that are connected together in a logically decoupled and physically decentralized manner using ring-type network. The central idea is to divide an instruction stream into blocks of instructions, and then exploit parallelism by executing these blocks using multiple processing elements. The multiscalar processor has generated wide interest, both in the academia and the industry, and seems to have tremendous potential to become the processing paradigm of choice for a circa 2000 intruction level parallel processor. The purpose of this research is to develop a high performance fault tolerant multiscalar processor and to provide an impetus to the incorporation of fault tolerance in general purpose processors. The primary manner fault tolerance will be incorporated in the multiscalar processor is by run-time replication of software and by executing the replicas on the processor's multiple execution units, which are provided for performance reasons. Two re-execution schemes (both using the same replication technique) are under investigation. Preliminary simulation studies have been conducted to get an idea of the performance loss incurred because of fault tolerance. These preliminary results indicate that time-redundant techniques are an excellent choice for providing fault tolerance in the multiscalar processor. ***