9639915
Support for adaptivity in ARMCI using migratable objects
Many new paradigms of parallel programming have emerged that compete with and complement the standard and well-established MPI model. Most notable, and successful, among these are models that support some form of global address space. At the same time, approaches based on migratable objects (also called virtualized processes) have shown that resource management concerns can be separated effectively from the overall parallel programming effort. For example, Charm++ supports dynamic load balancing via an intelligent adaptive run-time system. It is also becoming clear that a multi-paradigm approach that allows modules written in one or more paradigms to coexist and co-operate will be necessary to tame the parallel programming challenge. ARMCI is a remote memory copy library that serves as a foundation of many global address space languages and libraries. This paper presents our preliminary work on integrating and supporting ARMCI with the adaptive run-time system of Charm++ as a part of our overall effort in the multi-paradigm approach
16722634
Scaling applications to massively parallel machines using Projections performance analysis tool
Some of the most challenging applications to parallelize scalably are the ones that present a relatively small amount of computation per iteration. Multiple interacting performance challenges must be identified and solved to attain high parallel efficiency in such cases. We present case studies involving NAMD, a parallel classic molecular dynamics application for large biomolecular systems, and CPAIMD, Car-Parrinello ab initio molecular dynamics application, and efforts to scale them to large number of processors. Both applications are implemented in Charm++, and the performance analysis was carried out using Projections, the performance visualization/analysis tool associated with Charm++. We showcase a series of optimizations facilitated by Projections. The resultant performance of NAMD led to a Gordon Bell award at SC 2002 with unprecedented speedup on 3000 processors with teraflops level peak performance. We also explore the techniques for applying the performance visualization/analysis tool on future generation extreme-scale parallel machines and discuss the scalability issues with Projections.
13464889
Scaling Molecular Dynamics to 3000 Processors with Projections: A Performance Analysis Case Study
Some of the most challenging applications to parallelize scalably are the ones that present a relatively small amount of computation per iteration. Multiple interacting performance challenges must be identified and solved to attain high parallel efficiency in such cases. We present a case study involving NAMD, a parallel molecular dynamics application, and efforts to scale it to run on 3000 processors with Tera-FLOPS level performance. NAMD is implemented in Charm++, and the performance analysis was carried out using "projections", the performance visualization/analysis tool associated with Charm++. We will showcase a series of optimizations facilitated by projections. The resultant performance of NAMD led to a Gordon Bell award at SC2002.
40821829
Service class based online QoS management in surveillance radar systems
Many application level qualities are functions of available computation resources. Recent studies have handled the computation resource allocation problem to maximize the overall application quality. However such QoS problem is fundamentally a multi-dimensional optimization problem that requires extensive computation. Therefore, online usage of optimization procedures may significantly reduce the computation resource available for applications. This raises the question of how to best use the optimization procedures for dynamic real-time task sets. This paper proposes a method called service classes configuration to address the QoS problem with dynamic arrival and departure of tasks. A simplified radar application is used as an illustrative example.
1173830
A genetic-algorithm-based neighbor-selection strategy for hybrid peer-to-peer networks
BitTorrent is a popular, open-source, hybrid peer-to-peer content distribution system that is conducive for distribution of large-volume contents. In this paper, we propose a genetic-algorithm-based neighbor-selection strategy for hybrid peer-to-peer networks, which enhances the decision process performed at the tracker for transfer coordination. We also investigate how the strategy affects system throughput and distribution efficiency as well as peer contributions. We show through computer simulations that by increasing content availability to the clients from their immediate neighbors, it can significantly improve the system performance without trading off users' satisfaction. The proposed strategy can significantly improve the efficiency of distribution, especially for low-connectivity peers, and it is suitable to deploy for online decisions
12313444
Real time guarantee of aperiodic packets in single hop ad hoc wireless networks
Building real-time applications on 802.11 wireless networks is challenging because the medium access protocol is distributed and nodes contend for the channel nondeterministically. So far all attempts at providing real-time services in 802.11 require restrictive traffic assumptions such as periodicity. In this paper we describe distributed admission control, a modification to 802.11 that, when used with distributed prioritization, provides real-time guarantees for aperiodic packets. We show that barring external errors such as interference on the channel or incorrect priority scheduling this protocol guarantees deadlines will be met.
205046494
Run-time support For parallel functional programming on shared-memory multiprocessors
Abstract The use of functional languages for parallel computing has been proposed for many years. Many functional languages were developed along with the design of new architectures such as data flow and reduction machines. In this article, we present a general model of a run-time system for a parallel functional language called SISAL, to be executed on shared-memory multiprocessors. The implementation of this run-time system is examined on two radically different architectures: a 32-way (symmetrical) VAX Research Multiprocessor M31 and a 4-way Cray X-MP system. To properly evaluate the effectiveness of SISAL on shared-memory multiprocessors, we suggest further research explore an interactive visual control mechanism that dynamically shows run-time behavior.
14420598
A component-based approach for JavaCard runtime system development
In recent years a lot of research efforts have been directed towards component-based approach in the development of embedded operating systems. This allows the system to easily adapt itself to different hardware chips and various embedded application subsystems. Most of the existing research on component-based embedded system development is directed towards adapting the system to different hardware chips. However, this approach is not sufficient to port the system from one embedded application to another. In this research we will address the importance of component-based design at the application domain and runtime environment level of embedded systems. Since JavaCard is gaining importance in SmartCard embedded systems, we will design a component-based Java Card Runtime Environment and Application Subsystem. Our approach will enable easy configuration of the system to support Java Card, EMV-compliant card and various other smartcard embedded applications. Our research will demonstrate that the component-based approach allows the embedded operating system to easily port itself to other resource-constrained devices such as cell phones and other embedded system application with relative ease.