Global Lookahead Management (GLM) Protocol for Conservative DEVS Simulation

Jafer, Shafagh; Wainer, Gabriel

doi:10.1109/ds-rt.2010.37

Cited by 9 publications

(9 citation statements)

References 15 publications

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“…With this idea, the cost of the estimation is minimized and there is no unnecessary blocking, but the estimated LA could be too conservative. In addition, each LP or a central controller could block all LPs to take a static global observation for the LA estimation (e. g. [1] [16]). With this idea, the best LA is provided but it enforces to block all LPs as a global synchronization each time the estimation is done.…”

Section: B Solution With Conditional Look-aheadmentioning

confidence: 99%

Accelerating Distributed Discrete Event Simulation through Exchange of Conditional Look-Ahead

Fu¹,

Becker²,

Szczerbicka³

2014

2014 IEEE/ACM 18th International Symposium on Distributed Simulation and Real Time Applications

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Distributed discrete event simulation is a very important method today to analyze the behavior of large models. We investigate the practical implementation of distributed discrete event simulation with conservative synchronization and its acceleration through dynamic estimation of process-to-process look-ahead. Since the dynamic look-ahead changes with time, we have to face the situation, that the look-ahead between some logical processes is decreased temporarily. The shortened lookahead has a very negative influence to the performance of the simulation and it is hard to avoid. However, this effect can be reduced by introducing some extra mechanisms in the simulation.In this paper, we present a mechanism to optimize the simulation for the situation that the look-ahead between some processes is very short. This mechanism is based on exchange of conditional look-ahead and broadcast of invalidation announcement. Our evaluation shows reduction of the execution time of a majority of distributed simulations, especially when the estimated look-ahead is stochastically too conservative.

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Section: B Solution With Conditional Look-aheadmentioning

confidence: 99%

Accelerating Distributed Discrete Event Simulation through Exchange of Conditional Look-Ahead

Fu¹,

Becker²,

Szczerbicka³

2014

2014 IEEE/ACM 18th International Symposium on Distributed Simulation and Real Time Applications

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“…Second, the global state is determined. Each LP or a central controller has to block all LPs to obtain the static global observation for the LA estimation (e.g., ). This approach will deliver a better LA, however, at the expense of overhead, because it blocks all LPs with a global synchronization each time the estimation is done.…”

Section: Our Approachmentioning

confidence: 99%

Improving the performance of distributed discrete event simulation by exchange of conditional look‐ahead

Becker

Szczerbicka

2016

Concurrency and Computation

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Distributed discrete event simulation is an important approach for enabling the modeling and analysis of the behavior of large systems. This approach presents a major problem, namely, the possible low performance due to the excessive overhead in synchronizing the distributed logical processes. To counter this, our approach to distributed discrete event simulation involves conservative synchronization and its acceleration using dynamic estimation of process-to-process look-ahead with a feedback mechanism. This mechanism allows for the estimation of a larger look-ahead, which may be invalidated and recalculated during the course of the simulation, if one of the processes obtains more detailed knowledge.In this work, we extend the dynamically estimated look-ahead, on the basis of the local state of the logical processes, by exchanging conditional look-aheads, in conjunction with the broadcast of invalidation announcements. A notable reduction in runtime in various cases is thus achieved, especially when the estimated look-ahead is stochastically too conservative. Figure 4. Pseudocode of the algorithm.shorter than LA 2 1 and LA 3 1 . Furthermore, LP 2 sends CLA to LP 1 with the condition that LP 1 will not modify the state of LP 2 and LP 3 with external events. If LP 1 sends an external event to LP 2 , an IA will be sent to itself as discussed previously.This alternative solution can be seen as a trade-off between the external LAs and internal LAs. On one side, any LA sent from LP i to any LP in the same group is limited by min¹LA i k jLP k belongs to the other groupº:Conditional look-ahead (CLA) can be applied to extend these LAs anyway, but the limit must be kept. On the other side, the LA / CLA sent from LP i to any LP in the other group could be extended by a condition. Whether this condition really helps to extend the LA depends strongly on the model and the partitioning. This is generally unpredictable due to the unknown state of LPs in the same group. But in some special situations, the interruption of some immediate communication loops is useful.

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“…We can cite: parallelization approach , Balakrishnan et al, 1997, Glinsky and Wainer, 2006, Zacharewicz and Hamri, 2007, Jafer and Wainer, 2009; distribution [Kim et al, 2000, Liu, 2006, Zacharewicz and Hamri, 2007; and software approaches. These last approaches improve simulation time by getting rid of the hierarchical structure [Jafer and Wainer, 2010, Jafer and Wainer, 2009, Lowry et al, 2000, Zacharewicz and Hamri, 2007, and suggests to use direct coupling between models [Chen andVangheluwe, 2010, Muzy andNutaro, 2005]. The purpose of this article is to propose modifications to the simulation algorithms to reduce significantly the number of exchanged messages between components.…”

Section: Introductionmentioning

confidence: 99%

Decentralized Approach for Efficient Simulation of Devs Models

Franceschini

Bisgambiglia

2014

Progress in Pattern Recognition, Image Analysis, Computer Vision, and Applications

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This paper proposes to improve simulation efficiency of DEVS models based on the classical Discrete Event system Specification (DEVS) formalism by reducing the number of messages exchanged between simulators. We propose three changes: hierarchical modeling tree flattening based on closure under coupling, direct coupling and decentralized scheduling. The main idea is to relieve coordinators by giving to simulators more tasks to process.

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Global Lookahead Management (GLM) Protocol for Conservative DEVS Simulation

Cited by 9 publications

References 15 publications

Accelerating Distributed Discrete Event Simulation through Exchange of Conditional Look-Ahead

Accelerating Distributed Discrete Event Simulation through Exchange of Conditional Look-Ahead

Improving the performance of distributed discrete event simulation by exchange of conditional look‐ahead

Decentralized Approach for Efficient Simulation of Devs Models

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