Generating object lifetime traces with Merlin
Generating object lifetime traces with Merlin
复制标题
使用 Merlin 生成对象生命周期跟踪
DOI：
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发表时间：
2006
期刊：
影响因子：
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通讯作者：
D. Stefanovic
中科院分区：
文献类型：
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作者：
Matthew Hertz;S. Blackburn;J. E. B. Moss;Kathryn S. McKinley;D. Stefanovic
程序员正在编写需要垃圾收集的诸如Java和C＃之类的对象语言的迅速增长的程序。垃圾收集轨迹和模拟通过对物体生命行为以及对新垃圾收集算法的快速探索和设计进行更深入的了解，从而加快了研究。当生成完美的轨迹时，计算对象寿命的蛮力方法需要在程序中的每个潜在收集点上进行全叶垃圾收集。由于此过程非常昂贵，因此研究人员通常仅通过定期收集每32 kb的分配来使用颗粒状的痕迹。我们扩展了以两种方式模拟垃圾收集算法的最新技术。首先，我们开发了一种系统的方法来模拟复制垃圾收集的研究，并提出了痕量粒度对这些模拟的影响。我们表明，与完美的痕迹相比，痕量粒度通常会扭曲模拟垃圾收集结果。其次，我们介绍并测量一种称为Merlin的新算法的性能，用于计算对象寿命。 Merlin Timestamps对象，后来使用死对象的时间戳去世时重建。基本系统执行的垃圾收集的Merlin算法背包。实验结果表明，Merlin可以比在每个对象分配后收集的Brute Force方法快两个数量级的痕迹。我们还使用梅林（Merlin）产生堆行为的可视化，以暴露新的对象寿命行为。
Programmers are writing a rapidly growing number of programs in object-oriented languages, such as Java and C#, that require garbage collection. Garbage collection traces and simulation speed up research by enabling deeper understandings of object lifetime behavior and quick exploration and design of new garbage collection algorithms. When generating perfect traces, the brute-force method of computing object lifetimes requires a whole-heap garbage collection at every potential collection point in the program. Because this process is prohibitively expensive, researchers often use granulated traces by collecting only periodically, for example, every 32 KB of allocation.We extend the state of the art for simulating garbage collection algorithms in two ways. First, we develop a systematic methodology for simulation studies of copying garbage collection and present results showing the effects of trace granularity on these simulations. We show that trace granularity often distorts simulated garbage collection results compared with perfect traces. Second, we present and measure the performance of a new algorithm called Merlin for computing object lifetimes. Merlin timestamps objects and later uses the timestamps of dead objects to reconstruct when they died. The Merlin algorithm piggybacks on garbage collections performed by the base system. Experimental results show that Merlin can generate traces over two orders of magnitude faster than the brute-force method which collects after every object allocation. We also use Merlin to produce visualizations of heap behavior that expose new object lifetime behaviors.