The AXIOM software layers

AXIOM project aims at developing a heterogeneous computing board (SMP-FPGA).The Software Layers developed at the AXIOM project are explained.OmpSs provides an easy way to execute heterogeneous codes in multiple cores. People and objects will soon share the same digital network for information exchange in a world named as the age of the cyber-physical systems. The general expectation is that people and systems will interact in real-time. This poses pressure onto systems design to support increasing demands on computational power, while keeping a low power envelop. Additionally, modular scaling and easy programmability are also important to ensure these systems to become widespread. The whole set of expectations impose scientific and technological challenges that need to be properly addressed.The AXIOM project (Agile, eXtensible, fast I/O Module) will research new hardware/software architectures for cyber-physical systems to meet such expectations. The technical approach aims at solving fundamental problems to enable easy programmability of heterogeneous multi-core multi-board systems. AXIOM proposes the use of the task-based OmpSs programming model, leveraging low-level communication interfaces provided by the hardware. Modular scalability will be possible thanks to a fast interconnect embedded into each module. To this aim, an innovative ARM and FPGA-based board will be designed, with enhanced capabilities for interfacing with the physical world. Its effectiveness will be demonstrated with key scenarios such as Smart Video-Surveillance and Smart Living/Home (domotics).Peer ReviewedPostprint (author's final draft

Micro-threading and FPGA implementation of a RISC microprocessor : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Computer Science at Massey University, Palmerston North, New Zealand

Appendix E removed due to copyright restrictions. Articles are available in the print copy held in the libraryThis thesis is the outcome of research in two areas of computer technology: microprocessor and multi-processor architectures (specifically from the perspective of how differently they tolerate highly-latent and non-deterministic events), and hardware design of complex digital systems containing both datapath and control (particularly microprocessors). This thesis starts by pointing out that in order to achieve high processing speeds, current popular superscalar microprocessors (e.g. Intel Pentiums, Digital Alpha, etc) rely heavily on the technique of speculating the outcome of instruction flow in order to predict the behaviour of non-deterministic computing operations (as in loading operands from high-latency memory into the processor). This is fine only if the speculation is correct. But, what if it isn't? If the speculation fails, this would mean that the processor has to abandon its current decision (which now proved to be the wrong one) for the instruction flow path taken and to start all over again with the other path (the actual correct one). This is a waste of valuable processing time and hardware resources and a reduction of performance when speculation fails. Therefore, these processors can achieve high performance only when the majority of speculations are successful (being able to predict the right path). In an attempt to overcome the above shortcomings, the first part of this thesis is an investigation of the novel vector micro-threading architecture as an alternative approach to the current superscalar-based speculative microprocessor designs. Micro-threading is based on the not-so-novel multithreading technique, which avoids speculation altogether and instead, starts running a different thread of instructions while waiting for the non-determinism to be resolved. This utilizes the chip resources more efficiently without waste of any processing power. The rest of this thesis focuses on the baseline RISC processor platform, the MIPS R2000, which is reviewed first then partially synthesized from the RTL (Register Transfer Level) description using VHDL and then simulated and tested. This is conducted in order for future research to build upon and add the micro-threading architectural add-ons and modifications. Keywords: Micro-threading, Latency Tolerance, FPGA Synthesis, RISC Architecture, MIPS R2000 processor, VHDL

Fault Injection for Embedded Microprocessor-based Systems

Microprocessor-based embedded systems are increasingly used to control safety-critical systems (e.g., air and railway traffic control, nuclear plant control, aircraft and car control). In this case, fault tolerance mechanisms are introduced at the hardware and software level. Debugging and verifying the correct design and implementation of these mechanisms ask for effective environments, and Fault Injection represents a viable solution for their implementation. In this paper we present a Fault Injection environment, named FlexFI, suitable to assess the correctness of the design and implementation of the hardware and software mechanisms existing in embedded microprocessor-based systems, and to compute the fault coverage they provide. The paper describes and analyzes different solutions for implementing the most critical modules, which differ in terms of cost, speed, and intrusiveness in the original system behavio

TRIZ based Interface Conflict Resolving Strategies for Modular Product Architectures

In product development, the chosen product architecture often possesses characteristics of both modular and integral design. Within a modular architecture, a Function-Behavior-Structure (FBS) model has been applied to describe modules and their interfaces. To resolve emerging interface conflicts, several strategies based on both modular and integral action have been formulated. The strategies encompass TRIZ methods, as they focus strongly on product innovation. The purpose of the presented study is to combine TRIZ techniques and FBS modeling while trying to solve interface conflicts at a low level of abstraction. The interface conflict resolving strategies have been applied on an industrial case study successfull

Software-Based Self-Test of Set-Associative Cache Memories

Embedded microprocessor cache memories suffer from limited observability and controllability creating problems during in-system tests. This paper presents a procedure to transform traditional march tests into software-based self-test programs for set-associative cache memories with LRU replacement. Among all the different cache blocks in a microprocessor, testing instruction caches represents a major challenge due to limitations in two areas: 1) test patterns which must be composed of valid instruction opcodes and 2) test result observability: the results can only be observed through the results of executed instructions. For these reasons, the proposed methodology will concentrate on the implementation of test programs for instruction caches. The main contribution of this work lies in the possibility of applying state-of-the-art memory test algorithms to embedded cache memories without introducing any hardware or performance overheads and guaranteeing the detection of typical faults arising in nanometer CMOS technologie

Trace-level speculative multithreaded architecture

This paper presents a novel microarchitecture to exploit trace-level speculation by means of two threads working cooperatively in a speculative and non-speculative way respectively. The architecture presents two main benefits: (a) no significant penalties are introduced in the presence of a misspeculation and (b) any type of trace predictor can work together with this proposal. In this way, aggressive trace predictors can be incorporated since misspeculations do not introduce significant penalties. We describe in detail TSMA (trace-level speculative multithreaded architecture) and present initial results to show the benefits of this proposal. We show how simple trace predictors achieve significant speed-up in the majority of cases. Results of a simple trace speculation mechanism show an average speed-up of 16%.Peer ReviewedPostprint (published version