Load Stall Minimization

这个项目的想法源于对Java虚拟机上运行的Java基准测试的概要文件进行分析时的观察。我们观察到许多实例，其中概要文件中排名前10-20位的方法有80%左右的执行归因于少量指令，当我们查看这些指令时，执行时间似乎是由于加载停滞造成的。基于此，本项目的第一个目标是在选定的Java工作负载中确定停顿的来源，并尝试理解程序在停顿点的行为语义，以便我们可以对停顿进行分类。我们的目标是了解在哪里发生了摊位，并试图识别模式，以提供减少摊位的技术。减少延迟的可能方法分为两大类技术：1)指令调度和预取插入以减轻延迟和；2)改进对象在垃圾收集器中的位置。虽然这两种方法可以结合使用，但每种方法的好处和混合性能是未知的。

The genesis of the idea for this project was an observation made while performing the analysis of profiles from Java benchmarks being run on a Java virtual machine. We observed a number of instances where there were methods in the top 10-20 of the profile who had 80% or so of their execution attributed to a small number of instructions and that when we viewed those instructions the execution time appeared to be due to load stalls. Drawing from this the first goal in this project is to identify sources of stalls in a selection of Java workloads and try to understand the semantics of the program's behaviour at the point of the stall so we could classify the stalls. The goal is to understand where stalls are happening and try to identify patterns with a view to informing techniques to reduce the stalls. Possible approaches to reducing the stalls fall in two broad families of techniques: 1) instruction scheduling and prefetch insertion to mitigate the stalls and; 2) improve object placement in the garbage collector. While both approaches are possible in combination, the benefit of each and the blended performance is unknown.