Parameterized Time Warp (PTW): An Integrated Adaptive Solution to Optimistic PDES
Parameterized Time Warp (PTW): An Integrated Adaptive Solution to Optimistic PDES
复制标题
参数化时间扭曲 (PTW)：乐观 PDES 的集成自适应解决方案
DOI：
10.1006/jpdc.1996.0114
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发表时间：
1996
期刊：
影响因子：
--
通讯作者：
P. Wilsey
中科院分区：
文献类型：
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作者：
Avinash C. Palaniswamy;P. Wilsey
Time Warp是一种用于并行离散事件仿真的乐观同步协议。虽然Time Warp有可能减少大型仿真的执行时间，但它一直受到各种问题的困扰，即：1。回显和级联回滚造成的颠簸效应导致的不稳定性。2.由于状态保存和过度乐观导致的内存瓶颈。3.在每个处理节点上调度时间扭曲进程的调度算法效率低下。这些问题阻碍了Time Warp作为一种通用同步算法的广泛应用。试图解决这些问题的研究人员的总趋势是静态地限制时间扭曲的乐观。不幸的是，这些尝试只取得了有限的成功。这是因为一组静态参数可能对一个模拟效果良好，但对另一个模拟效果不佳。本文使用自适应机制来控制乐观主义，使用称为有用工作的性能指标来解决这个问题。本研究针对上述问题提出了解决方案，具体如下：1.使用自适应有界时间窗口稳定时间扭曲。2.通过使用自适应机制来改变检查点间隔，减少内存使用和总执行时间。3.使用有用的工作参数调度时间扭曲进程，以支持更高效的进程。使用这个新的性能指标称为有用的工作，时间扭曲的几个修改实施，以稳定和改善时间扭曲。因此，这种新的改进的时间扭曲同步机制称为参数化时间扭曲提供了一个完整的自适应解决方案，乐观的并行离散事件仿真。经验工作表明，PTW优于类似的分区和负载条件下执行的等效时间扭曲模拟。
Time Warp is an optimistic synchronization protocol used for parallel discrete event simulation. While Time Warp has the potential to reduce the execution time of large simulations, it has been plagued by a variety of problems, namely: 1. Instability due to thrashing effects caused by echoing and cascading rollbacks. 2. Memory bottlenecks due to state saving and excessive optimism. 3. Inefficient scheduling algorithms for scheduling Time Warp processes on each processing node. These problems have inhibited the widespread use of Time Warp as a general purpose synchronization algorithm. The general trend of researchers attempting to solve these problems has been to statically limit the optimism of Time Warp. Unfortunately, these attempts have achieved only limited success. This is because a static set of parameters may perform well for one simulation but not for another. This paper attacks the problem using adaptive mechanisms to control optimism, using an index of performance called useful work. This research presents solutions for the above mentioned problems, by: 1. Stabilizing Time Warp using adaptive bounded time windows. 2. Reducing memory usage and overall execution time by using an adaptive mechanism to vary the checkpoint interval. 3. Scheduling Time Warp processes with the useful work parameter to favor more productive processes. Using this new performance index called Useful Work, several modifications to Time Warp are implemented to stabilize and improve Time Warp. Thus, this new improved Time Warp synchronization mechanism termed Parameterized Time Warp provides an integrated adaptive solution to optimistic Parallel Discrete Event Simulation. Empirical work showing that PTW outperforms an equivalent Time Warp simulation executing under similar partitioning and load conditions is also presented.