Copyright © 2006, by the author(s).

Many scientific applications that run on today’s multiprocessors, such as weather forecasting and seismic analysis, are bottlenecked by their file-I/O needs. Even if the multiprocessor is configured with sufficient I/O hardware, the file-system software often fails to provide the available bandwidth to the application. Although libraries and enhanced file-system interfaces can make a significant improvement, we believe that fundamental changes are needed in the file-server software. We propose a new technique, disk-directed I/O, to allow the disk servers to determine the flow of data for maximum performance. Our simulations show that tremendous performance gains are possible. Indeed, disk-directed I/O provided consistent high performance that was largely independent of data distribution, obtained up to 93 % of peak disk bandwidth, and was as much as 16 times faster than traditional parallel file systems.

Lightweight threads have an important role to play in parallel systems: they can be used to exploit shared-memory parallelism, to mask communication and I/O latencies, to implement remote memory access, and to support task-parallel and irregular applications. In this paper, we address the question of how to integrate threads and communication in high-performance distributed-memory systems. We propose an approach based on global pointer and remote service request mechanisms, and explain how these mechanisms support dynamic communication structures, asynchronous messaging, dynamic thread creation and destruction, and a global memory model via interprocessor references. We also explain how these mechanisms can be implemented in various environments. Our global pointer and remote service request mechanisms have been incorporated in a runtime system called Nexus that is used as a compiler target for parallel languages and as a substrate for higher-level communication libraries. We report the results of performance studies conducted using a Nexus implementation; these results indicate that Nexus mechanisms can be implemented efficiently on commodity hardware and software systems. 1

Cyber-Physical Systems (CPS) are integrations of computation and physical processes. Embedded computers and networks monitor and control the physical processes, usually with feedback loops where physical processes affect computations and vice versa. The economic and societal potential of such systems is vastly greater than what has been realized, and major investments are being made worldwide to develop the technology. There are considerable challenges, particularly because the physical components of such systems introduce safety and reliability requirements qualitatively different from those in generalpurpose computing. Moreover, physical components are qualitatively different from object-oriented software components. Standard abstractions based on method calls and threads do not work. This paper examines the challenges in designing such systems, and in particular raises the question of whether today’s computing and networking technologies provide an adequate foundation for CPS. It concludes that it will not be sufficient to improve design processes, raise the level of abstraction, or verify (formally or otherwise) designs that are built on today’s abstractions. To realize the full potential of CPS, we will have to rebuild computing and networking abstractions. These abstractions will have to embrace physical dynamics and computation in a unified way. 1

this article, we describe an execution model for supporting programs that use pointer-based dynamic data structures. This model uses a simple mechanism for migrating a thread of control based on the layout of heap-allocated data and introduces parallelism using a technique based on futures and lazy task creation. We intend to exploit this execution model using compiler analyses and automatic parallelization techniques. We have implemented a prototype system, which we call Olden, that runs on the Intel iPSC/860 and the Thinking Machines CM-5. We discuss our implementation and report on experiments with five benchmarks.

The continuation of the remarkable exponential increases in processing power over the recent past faces imminent challenges due in part to the physics of deep-submicron CMOS devices and the costs of both chip masks and future fabrication plants. A promising solution to these problems is offered by an alternative to CMOS-based computing, chemically assembled electronic nanotechnology (CAEN). In this paper we outline how CAEN-based computing can become a reality. We briefly describe recent work in CAEN and how CAEN will affect computer architecture. We show how the inherently reconfigurable nature of CAEN devices can be exploited to provide high-density chips with defect tolerance at significantly reduced manufacturing costs. We develop a layered abstract architecture for CAEN-based computing devices and we present preliminary results which indicate that such devices will be competitive with CMOS circuits.

Abstract. This paper introduces a new portable communication library called ARMCI. ARMCI provides one-sided communication capabilities for distributed array libraries and compiler run-time systems. It supports remote memory copy, accumulate, and synchronization operations optimized for non-contiguous data transfers including strided and generalized UNIX I/O vector interfaces. The library has been employed in the Global Arrays shared memory programming toolkit and Adlib, a Parallel Compiler Run-time Consortium run-time system. 1

We present Sequoia, a programming language designed to facilitate the development of memory hierarchy aware parallel programs that remain portable across modern machines featuring different memory hierarchy configurations. Sequoia abstractly exposes hierarchical memory in the programming model and provides language mechanisms to describe communication vertically through the machine and to localize computation to particular memory locations within it. We have implemented a complete programming system, including a compiler and runtime systems for Cell processor-based blade systems and distributed memory clusters, and demonstrate efficient performance running Sequoia programs on both of these platforms.

The goal of the Olden project is to build a system that provides parallelism for general purpose C programs with minimal programmer annotations. We focus on programs using dynamic structures such as trees, lists, and DAGs. We demonstrate that providing both software caching and computation migration can improve the performance of these programs, and provide a compile-time heuristic that selects between them for each pointer dereference. We have implemented a prototype system on the Thinking Machines CM-5. We describe our implementation and report on experiments with ten benchmarks.

BSPlib is a small communications library for bulk synchronous parallel (BSP) programming which consists of only 20 basic operations. This paper presents the full definition of BSPlib in C, motivates the design of its basic operations, and gives examples of their use. The library enables programming in two distinct styles: direct remote memory access using put or get operations, and bulk synchronous message passing. Currently, implementations of BSPlib exist for a variety of modern architectures, including massively parallel computers with distributed memory, shared memory multiprocessors, and networks of workstations. BSPlib has been used in several scientific and industrial applications; this paper briefly describes applications in benchmarking, Fast Fourier Transforms, sorting, and molecular dynamics.