Introduction to C+- (Submicron Systems Architecture Project)

[No abstract available

The Architecture and Programming of a Fine-Grain Multicomputer

The research presented in this thesis was conducted in the context of the Mosaic C, an experimental, fine-grain multicomputer. The objective of the Mosaic experiment was to develop a concurrent-computing system with maximum performance per unit cost, while still retaining a general-purpose application span. A stipulation of the Mosaic project was that the complexity of a Mosaic node be limited by the silicon complexity available on a single VLSI chip. The two most important original results reported in the thesis are: (1) The design and implementation of C+-, a concurrent, object-oriented programming system. Syntactically, C+- is an extension of C++. The concurrent semantics of C+- are contained within the process concept. A C+- process is analogous to a C++ object, but it is also an autonomous computing agent, and a unit of potential concurrency. Atomic single-process updates that can be individually enabled and disabled are the execution units of the concurrent computation. The limited set of primitives that C+- provides is shown to be sufficient to express a variety of concurrent-programming problems concisely and efficiently. An important design requirement for C+- was that efficient implementations should exist on a variety of concurrent architectures, and, in particular, on the simple and inexpensive hardware of the Mosaic node. The Mosaic runtime system was written entirely in C+-. (2) Pipeline synchronization, a novel, generally- applicable technique for hardware synchronization. This technique is a simple, low-cost, high-bandwidth, high- reliability solution to interfaces between synchronous and asynchronous systems, or between synchronous systems operating from different clocks. The technique can sustain the full communication bandwidth and achieve an arbitrarily low, non-zero probability of synchronization failure, Pf, with the price in both latency and chip area being O(log 1/Pf). Pipeline synchronization has been successfully applied to the highperformance inter-computer communication in Mosaic node ensembles

Pipeline Synchronization

Pipeline synchronization is a simple, low-cost, highbandwidth, high-reliability solution to interfaces between synchronous and asynchronous systems, or between synchronous systems operating from different clocks. The technique can sustain maximum communication bandwidth while achieving an arbitrarily low, nonzero probability of synchronization failure, P f , with the price in both latency and chip area being O(log 1 Pf ). Pipeline synchronization has been successfully applied to high-performance inter-computer communication in multicomputers [13, 15] and local-area networks [3, 7]. 1 Problem Specification Given the required rate of data transfer of E events per second between an asynchronous and a synchronous system, with each event delivering W bits of information, design an interface that will guarantee that the probability of synchronization failure be less than a given P f ? 0. The assumption is that the flow control is implemented as either a two-phase or four-phase signalin..

The Reactive Kernel

No abstract

Myrinet: A Gigabit-per-Second Local Area Network

Abstract. Myrinet is a new type of local-area network (LAN) based on the technology used for packet communication and switching within "massivelyparallel processors " (MPPs). Think of Myrinet as an MPP message-passing network that can span campus dimensions, rather than as a wide-area telecommunications network that is operating in close quarters. The technical steps toward making Myrinet a reality included the development of (1) robust, 25m communication channels with flow control, packet framing, and error control; (2) self-initializing, low-latency, cut-through switches; (3) host interfaces that can map the network, select routes, and translate from network addresses to routes, as well as handle packet traffic; and (4) streamlined host software that allows direct communication between user processes and the network. Background. In order to understand how Myrinet differs from conventional LANs such as Ethernet and FDDI, it is helpful to start with Myrinet's genealogy. Myrinet is rooted in the results of two ARPA-sponsored research projects, the Caltech Mosaic, an experimental, fine-grain multicomputer [1], and the USC Information Sciences Institute (USC/ISI) ATOMIC LAN [2, 3], which was built using Mosaic components. Myricom, Inc., is a startup company founded by members of these two research projects. Multicomputer Message-Passing Networks. A multicomputer [4, 5] is an MPP architecture consisting of a collection of computing nodes, each with its own memory, connected by a message-passing network. The Caltech Mosaic was an experiment to "push the envelope " of multicomputer design and programming toward a system with up to tens of thousands of small, single-chip nodes rather than hundreds of circuit-board-size nodes. The fine-grain multicomputer places more extreme demands on the messagepassing network due to the larger number of nodes and a greater interdependence between the computing processes on different nodes. The message-passing-network technology developed for the Mosaic [6] achieved its goals so well that it was used in several other MPP systems, including th