| 1. |
- Lindén, Jonatan, et al.
(författare)
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Exposing inter-process information for efficient parallel discrete event simulation of spatial stochastic systems
- 2017
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Ingår i: Proc. 5th ACM SIGSIM Conference on Principles of Advanced Discrete Simulation. - New York : ACM Press. - 9781450344890 ; , s. 53-64
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Konferensbidrag (refereegranskat)abstract
- We present a new efficient approach to the parallelization of discrete event simulators for multicore computers, which is based on exposing and disseminating essential information between processors. We aim specifically at simulation models with a spatial structure, where time intervals between successive events are highly variable and without lower bounds. In Parallel Discrete Event Simulation (PDES), the model is distributed onto parallel processes. A key challenge in PDES is that each process must continuously decide when to pause its local simulation in order to reduce the risk of expensive rollbacks caused by future "delayed"' incoming events from other processes. A process could make such decisions optimally if it would know the timestamps of future incoming events. Unfortunately, this information is often not available in PDES algorithms. We present an approach to designing efficient PDES algorithms, in which an existing natural parallelization of PDES is restructured in order to expose and disseminate more precise information about future incoming events to each LP. We have implemented our approach in a parallel simulator for spatially extended Markovian processes, intended for simulating, e.g., chemical reactions, biological and epidemiological processes. On 32 cores, our implementation exhibits speedup that significantly outweighs the overhead incurred by the refinement. We also show that our resulting simulator is superior in performance to existing simulators for comparable models, achieving for 32 cores an average speedup of 20 relative to an efficient sequential implementation.
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| 2. |
- Serror, Martin, et al.
(författare)
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Code-Transparent Discrete Event Simulation for Time-Accurate Wireless Prototyping
- 2017
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Ingår i: SIGSIM-PADS 2017 - Proceedings of the 2017 ACM SIGSIM Conference on Principles of Advanced Discrete Simulation. - New York, NY, USA : Association for Computing Machinery (ACM). - 9781450344890 ; , s. 161-172
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Konferensbidrag (refereegranskat)abstract
- Exhaustive testing of wireless communication protocols on prototypical hardware is costly and time-consuming. An alternative approach is network simulation, which, however, often strongly abstracts from the actual hardware. Especially in the wireless domain, such abstractions often lead to inaccurate simulation results. Therefore, we propose a code-transparent discrete event simulator that enables a direct simulation of existing code for wireless prototypes. With a focus on lower layers of the communication stack, we enable a parametrization of the simulation timings based on real-world measurements to increase the simulation accuracy. Our evaluation shows that we achieve close results for throughput (deviation below 3 % for UDP) and latency (corrected deviation about 13 %) compared to real-world setups, while providing the benefits of code-transparent simulation, i.e., to flexibly simulate large topologies with existing prototype code. Moreover, we demonstrate that our approach finds implementation defects in existing hardware prototype software, which are otherwise difficult to track down in real deployments.
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