We describe the TED/C++ implementation of WIPPET, a parallelsimulation testbed for evaluating radio resource management algorithms and wireless transport protocols. Versions 0.3 and 0.4 of the testbed model radio pro...
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We describe the TED/C++ implementation of WIPPET, a parallelsimulation testbed for evaluating radio resource management algorithms and wireless transport protocols. Versions 0.3 and 0.4 of the testbed model radio propagation (long- and short-scale fading and interference) and protocols for integrated radio resource management in mobile wireless voice networks including the standards based AMPS, NA-TDMA and GSM protocols, and several research oriented protocol families. We provide parallel performance data verifying that the dominant computational demand due to received signal quality calculation can be partitioned geographically by orthogonal radio channels, or in a hybrid manner.
CCS is a resource management system for parallel high-performance computers. At the user level, CCS provides vendor-independent access to parallel systems. At the system administrator level, CCS offers tools for contr...
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CCS is a resource management system for parallel high-performance computers. At the user level, CCS provides vendor-independent access to parallel systems. At the system administrator level, CCS offers tools for controlling (i.e, specifying, configuring and scheduling) the system components that are operated in a computing center. Hence the name "Computing Center Software". CCS provides: hardware-independent scheduling of interactive and batch jobs; partitioning of exclusive and non-exclusive resources; open, extensible interfaces to other resource management systems; a high degree of reliability (e.g. automatic restart of crashed daemons); fault tolerance in the case of network breakdowns. The authors describe CCS as one important component for the access, job distribution, and administration of networked HPC systems in a metacomputing environment.
With the emerging of broadband networks based on ATM technology, performance evaluation tools that allow the study of large systems are desperately needed. We present our experiments in distributedsimulation of large...
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With the emerging of broadband networks based on ATM technology, performance evaluation tools that allow the study of large systems are desperately needed. We present our experiments in distributedsimulation of large and complex ATM network models with a conservative simulator. The goal here was not to achieve the maximum speedup with well shaped topologies bat rather to see what speedup can be obtained with a realistic model on a "state of the art" parallel computer. A network model with 78 switches is simulated on a Cray T3E using 3 different traffic loads. The performance results show that good speedups can be achieved but they also highlight partitioning problems and bottlenecks in the simulation model that can seriously limit the speedup of realistic model simulations.
A number of library based parallel and sequential network simulators have been designed. The paper describes a library, called GloMoSim (Global Mobile system Simulator), for parallelsimulation of wireless networks. G...
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A number of library based parallel and sequential network simulators have been designed. The paper describes a library, called GloMoSim (Global Mobile system Simulator), for parallelsimulation of wireless networks. GloMoSim has been designed to be extensible and composable: the communication protocol stack for wireless networks is divided into a set of layers, each with its own API. Models of protocols at one layer interact with those at a lower (or higher) layer only via these APIs. The modular implementation enables consistent comparison of multiple protocols at a given layer. The parallel implementation of GloMoSim can be executed using a variety of conservative synchronization protocols, which include the null message and conditional event algorithms. The paper describes the GloMoSim library, addresses a number of issues relevant to its parallelization, and presents a set of experimental results on the IBM 9076 SP, a distributed memory multicomputer. These experiments use models constructed from the library modules.
We consider the distributedsimulation of queueing networks of FCFS servers with infinite buffers, and irreducible Markovian routing. We first show that for either the conservative or optimistic synchronization protoc...
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We consider the distributedsimulation of queueing networks of FCFS servers with infinite buffers, and irreducible Markovian routing. We first show that for either the conservative or optimistic synchronization protocols the simulation of such networks can prematurely block owing to event buffer exhaustion. Buffer exhaustion can occur in the simulator, whether or not the simulator is stable, and, unlike simulators of feedforward networks, cannot be prevented by interprocessor flow control alone. We propose a simple technique (which we call compactification), which, when used in conjunction with interprocessor flow control, prevents buffer exhaustion. This leads to a general algorithm, for both conservative and optimistic synchronization, that allows one to simulate the queueing network within the finite amount of memory available at each processor. For each algorithm presented, we also provide the proof that it cannot get deadlocked owing to buffer exhaustion.
Data-parallel applications executing in multi-user clustered environments share resources with other applications. Since this sharing of resources dramatically affects the performance of individual applications, it is...
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Data-parallel applications executing in multi-user clustered environments share resources with other applications. Since this sharing of resources dramatically affects the performance of individual applications, it is critical to estimate its effect, i.e., the application slowdown, in order to predict application behavior. The authors develop a new approach for predicting the slowdown imposed on data-parallel applications executing on homogeneous and heterogeneous clusters of workstations. The model synthesizes the slowdown on each machine used by an application into a contention measure-the aggregate slowdown factor-used to adjust the execution time of the application to account for the aggregate load. The model is parameterized by the work (or data) partitioning policy employed by the targeted application, the local slowdown (due to contention from other users) present in each node of the cluster and the relative weight (capacity) associated with each node in the cluster. This model provides a basis for predicting realistic execution times for distributed data-parallel applications in production clustered environments.
We present a dynamic load balancing algorithm for parallel discrete event simulation of spatially explicit problems. In our simulations, the space is discretized and divided into subareas, each of which is simulated b...
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We present a dynamic load balancing algorithm for parallel discrete event simulation of spatially explicit problems. In our simulations, the space is discretized and divided into subareas, each of which is simulated by a logical process (LP). Load predictions are done based on the future events that are scheduled for a given LP. The information about the load of the processes is gathered and distributed during the Global Virtual Time calculation. Each LP calculates the new load distribution of the system. The load is then balanced by moving spatial data between neighboring LPs in one round of communications. In our problems, the LPs should be described as being elements of a ring from the point of view of communication. Due to the spatial characteristics, the load can be migrated only between neighboring LPs. We present an algorithm that performs the load balancing in a ring and minimizes the maximum after-balance load.
The paper presents an analytical model for evaluating the performance of Time Warp simulators. The proposed model is formalized based on two important time components in parallel and distributed processing: computatio...
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ISBN:
(纸本)0818684577
The paper presents an analytical model for evaluating the performance of Time Warp simulators. The proposed model is formalized based on two important time components in parallel and distributed processing: computation time and communication time. The communication time is modeled by buffer access time and message transmission time. Logical processes of the Time Warp simulation, and the processors executing them are assumed to be homogeneous. Performance metrics such as rollback probability, rollback distance, elapsed time and Time Warp efficiency are derived. More importantly, we also analyze the impact of cascading rollback waves on the overall Time Warp performance. By rendering the deviation in state numbers of sender-receiver pairs, we investigate the performance of throttled Time Warp scheme. Our analytical model shows that the deviation in state numbers and the communication delay have a profound impact on Time Warp efficiency. The performance model has been validated against implementation results obtained on a Fujitsu AP3000 parallel computer. The analytical framework can be readily used to estimate performance before the Time Warp simulator is implemented.
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