10416010
MegaProto: 1 TFlops/10kW Rack Is Feasible Even with Only Commodity Technology
In our research project "Mega-Scale Computing Based on Low-Power Technology and Workload Modeling", we claim that a million-scale parallel system could be built with densely mounted low-power commodity processors. "MegaProto" is a proof-of-concept low-power and highperformance cluster build only with commodity components to implement this claim. A one-rack system is composed of 32 motherboard "cluster units" of 1 U-height and commodity switches to interconnect them mutually as well as with other racks. Each cluster unit houses 16 low-power dollarbill- sized commodity PC-architecture daughterboards, together with a high bandwidth, 2 Gbps per processor embedded switched network based on Gigabit Ethernet. The peak performance of a one-rack system is 0.48 TFlops for the first version and will improve to 1.02 TFlops in the second version through a processor/daughterboard upgrade. The system consumes about 10 kW or less per rack, resulting in 100 MFlops/W power efficiency with a power-aware intrarack network of 32 Gbps bisection bandwidth, while additional 2.4 kW will boost this to sufficiently large 256 Gbps. Performance studies show that even the first version significantly outperforms a conventional high-end 1U server comprised of dual power-hungry processors in a majority of NPB programs. It is also investigated how the current automated DVS control could save power for the HPC parallel programs along with its limitation.
12665758
Direct Execution of Linux Binary on Windows for Grid RPC Workers
Local area or campus-type networks consist of PCs using different operating systems such as Windows and Linux. These PCs are expected to have enormous potential computing power for grid computing. The majority of PCs in this type of environment run on Windows, while grid applications and middleware are often developed on Linux. The challenge is to absorb the heterogeneity of operating systems. Grid RPC is a promising programming model for the development of grid applications. We have designed and implemented an agent called BEE, which enables direct execution of Linux binary programs on Windows for a grid RPC worker. We have integrated the BEE agent into an OmniRPC system in order to make use of Windows PCs as computing resources in a hybrid grid environment combining Windows PCs into grid computing resources. The BEE agent allows Linux binaries of the program of the OmniRPC worker to be exported and run under Windows without any modification of its Linux binaries. The results of our experiments show that the performance of a worker program using BEE is almost the same as that of Windows native binary and Cygwin and is better that that of using VMware. We have demonstrated a hybrid grid environment combining Window PCs in a conventional grid of Linux nodes.
195869612
The EM-X parallel computer: architecture and basic performance
Latency tolerance is essential in achieving high performance on parallel computers for remote function calls and fine-grained remote memory accesses. EM-X supports interprocessor communication on an execution pipeline with small and simple packets. It can create a packet in one cycle, and receive a packet from the network in the on-chip buffer without interruption. EM-X invokes threads on packet arrival, minimizing the overhead of thread switching. It can tolerate communication latency by using efficient multi-threading and optimizing packet flow of fine grain communication. EM-X also supports the synchronization of two operands, direct remote memory read/write operations and flexible packet scheduling with priority. The paper describes distinctive features of the EM-X architecture and reports the performance of small synthetic programs and larger more realistic programs.
32545241
Ninf: A Network Based Information Library for Global World-Wide Computing Infrastructure
Ninf is an ongoing global network-wide computing infrastructure project which allows users to access computational resources including hardware, software and scientific data distributed across a wide area network. Ninf is intended not only to exploit high performance in network parallel computing, but also to provide high quality numerical computation services and accesses to scientific database published by other researchers. Computational resources are shared as Ninf remote libraries executable at a remote Ninf server. Users can build an application by calling the libraries with the Ninf Remote Procedure Call, which is designed to provide a programming interface similar to conventional function calls in existing languages, and is tailored for scientific computation. In order to facilitate location transparency and network-wide parallelism, Ninf metaserver maintains global resource information regarding computational server and databases, allocating and scheduling coarse-grained computation for global load balancing. Ninf also interfaces with the WWW browsers for easy accessibility.
6990232
OmniRPC: A Grid RPC Facility for Cluster and Global Computing in OpenMP
Omni remote procedure call facility, OmniRPC, is a thread-safe grid RPC facility for cluster and global computing environments. The remote libraries are implemented as executable programs in each remote computer, and OmniRPC automatically allocates remote library calls dynamically on appropriate remote computers to facilitate location transparency. We propose to use OpenMP as an easy-to-use and simple programming environment for the multi-threaded client of OmniRPC. We use the POSIX thread implementation of the Omni OpenMP compiler which allows multi-threaded execution of OpenMP programs by POSIX threads even in a single processor. Multiple outstanding requests of OmniRPC calls in OpenMP work-sharing construct are dispatched to different remote computers to exploit network-wide parallelism.
3176337
EMC-Y: parallel processing element optimizing communication and computation
EMC-Y is a new processing element for highly parallel computers designed to achieve high performance parallel computation by fusing a dataflow mechanism and a von Neumann execution pipeline. We have already developed EMC-R, which is the processing element used in the EM-4 prototype. EMC-Y improves on EMC-R's packet communication performance, allowing it to tolerate a more network traffic. This paper presents the architecture of EMC-Y, concentrating on the principles of packet communication. EMC-Y uses an output packet buffer and optimal packet routing to improve the performance of packet sending and transferring. EMC-Y changes the memory access priority for input packet buffer operation to improve the performance of receiving packets. Since the EMC-Y processor not only improves the performance of packet input and output but also balances them, it can tolerate a large amount of traffic and can improve the execution performance. We evaluate the improvements of EMC-Y architecture using a clock level simulator. The results show that EMC-Y improves performance by 50% to 70% in several programs over EMC-R at the same clock speed.
1796136
Strong normalizability of the non-deterministic catch/throw calculi
The catch/throw mechanism in Common Lisp provides a simple control mechanism for non-local exits. We study typed calculi by Nakano and Sato which formalize the catch/throw mechanism. These calculi correspond to classical logic through the Curry-Howard isomorphism, and one of their characteristic points is that they have non-deterministic reduction rules. These calculi can represent various computational meaning of classical proofs. This paper is mainly concerned with the strong normalizability of these calculi. Namely, we prove the strong normalizability of these calculi, which was an open problem. We first formulate a non-deterministic variant of Parigot's λμ-calculus, and show it is strongly normalizing. We then translate the catch/throw calculi to this variant. Since the translation preserves typing and reduction, we obtain the strong normalization of the catch/throw calculi. We also briefly consider second-order extension of the catch/throw calculi. Copyright 2002 Elsevier Science B.V
27739305
Explicit Environments
We introduce λƐ, a simply typed calculus with environments as first class values. As well as the usual constructs of λ and application, we have e[[a]] which evaluates term a in an environment e. Our environments are a set of variable-value pairs, but environments can also be computed by function application and evaluation in some other environments. The notion of environments here is a generalization of explicit substitutions and records. We show that the calculus has desirable properties such as subject reduction, confluence, conservativity over the simply typed λβ-calculus and strong normalizability.
46610662
CAL: A Computer Assisted Learning System for Computation and Logic
In this paper, we describe a computer system CAL which assists students' understanding of a lecture course in logic and computation. We introduce a new foundational theory of expressions, which is inspired by the theory of expressions due to Martin-Lof [6], and use the expressions determined by the theory to implement various syntactic objects in CAL. We also introduce the concept of derivation game, and show that various logical and computational systems given in the lecture course can be defined uniformly by derivation games.
43544513
Conservativeness of Lambda over lambda-sigma-Calculus
27411446
A Purely Functional Language with Encapsulated Assignment
We introduce a new functional programming language with assignment. The language, which we call Λ, is a conservative extension of the λβ-calculus, and as such it it a higher order functional language in which we can manipulate functions as first class objects. Λ has a lazy evaluation semantics and Λ programs can be evaluated in parallel. Λ also supports imperative programming in terms of assignments. All the assingments in Λ are encapsulated within suitable scope of the let constructs. The language is therefore side-effect free and referentially transparent. We show by an example that we can smoothly reason about Λ programs.