A general model of concurrency and its implementation as many-core dynamic RISC processors

Abstract

A general model of concurrency and its implementation as many-core dynamic RISC processors Bernard, T.A.M.; Bousias, K.; Guang, L.; Jesshope, C.R.; Lankamp, M.; van Tol, M.W.; Zhang, L. General rightsIt is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content license (like Creative Commons). Disclaimer/Complaints regulationsIf you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: http://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. Abstract-This paper presents a concurrent execution model and its micro-architecture based on in-order RISC processors, which schedules instructions from large pools of contextualised threads. The model admits a strategy for programming chip multiprocessors using parallelising compilers based on existing languages. The model is supported in the ISA by number of instructions to create and manage abstract concurrency. The paper estimates the cost of supporting these instructions in silicon. The model and its implementation uses dynamic parameterisation of concurrency creation, where a single instruction captures asynchronous remote function execution, mutual exclusion and the execution of a general concurrent loop structure and all associated communication. Concurrent loops may be dependent or independent, bounded or unbounded and may be nested arbitrarily. Hierarchical concurrency allows compilers to restructure and parallelise sequential code to meet the strict constraints on the model, which provide its freedom from deadlock and locality of communication. Communication is implicit in both the model and micro-architecture, due to the dynamic distribution of concurrency. The result is location-independent binary code that may execute on any number of processors. Simulation and analysis of the micro-architecture indicate that the model is a strong candidate for the exploitation of many-core processors. The results show near-linear speedup over two orders of magnitude of processor scaling, good energy efficiency and tolerance to large latencies in asynchronous operations. This is true for both independent threads as well as for reductions.

On-chip traffic regulation to reduce coherence protocol cost on a microthreaded many-core architecture with distributed caches

“…Its success can be shown from the good scalability and flexibility over a range of benchmarks running on the Micro Grid [Bousias et al 2006;Bernard et al 2008;Yang et al 2011;]. However, It may be injected into another L2 cache with empty slot or matched tag, or retired to DRAM.…”

Ariadne — Directive-based parallelism extraction from recursive functions

“…SVP [3], [4], [5] is a multi-core architecture and programming model that The first and the last thread in the previous process reads and writes values from and to the shared memory. The shared memory is used for the storage of scalar and array data.…”

Multiple Levels of Abstraction in the Simulation of Microthreaded Many-Core Architectures

“…Cycle-accurate models: The design of the architecture stays fluid through simulation in order to realize a validated system in silicon and to provide further optimizations in the silicon chip. The most commonly used simulation technique in academia and industry is the detailed, event-driven simulation of all the components of the architecture [7] [19]. Detailed simulation is generally the first step in the design process of an architecture soon after pen and paper model and analytical models.…”