Perf&Fair: A Progress-Aware Scheduler to Enhance Performance and Fairness in SMT Multicores
Perf&Fair: A Progress-Aware Scheduler to Enhance Performance and Fairness in SMT Multicores
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性能
DOI：
10.1109/tc.2016.2620977
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发表时间：
2017
影响因子：
3.7
通讯作者：
J. Duato
中科院分区：
文献类型：
--
作者：
Josué Feliu;J. Sahuquillo;S. Petit;J. Duato
如今，高性能多核处理器具备多线程能力。在这些处理器上并发运行的进程不断竞争共享资源，不仅在核之间，而且在核内部。虽然资源共享提高了资源利用率，但访问共享资源的进程之间的干扰会强烈影响单个进程的性能及其可预测性。在这种情况下，进程调度在处理性能和公平性方面起着关键作用。在这项工作中，我们提出了一种用于同时多线程（SMT）多核的进程调度器，它同时解决性能和公平性问题。这是一个主要的设计问题，因为仅针对两个目标中的一个进行调度往往会损害另一个目标。为了解决性能问题，调度器解决一级缓存和主存的带宽争用问题。为了处理公平性问题，调度器估计进程所经历的进展情况，并优先考虑累计进展较低的进程。在具有六个双线程同时多线程核心的英特尔至强E5645上的实验结果表明，与两种最先进的调度器以及Linux操作系统调度器相比，所提出的调度器在性能和公平性方面都有所提高。与Linux相比，不公平性降低了一半，同时性能仍提高了5.6%。
Nowadays, high performance multicore processors implement multithreading capabilities. The processes running concurrently on these processors are continuously competing for the shared resources, not only among cores, but also within the core. While resource sharing increases the resource utilization, the interference among processes accessing the shared resources can strongly affect the performance of individual processes and its predictability. In this scenario, process scheduling plays a key role to deal with performance and fairness. In this work we present a process scheduler for SMT multicores that simultaneously addresses both performance and fairness. This is a major design issue since scheduling for only one of the two targets tends to damage the other. To address performance, the scheduler tackles bandwidth contention at the L1 cache and main memory. To deal with fairness, the scheduler estimates the progress experienced by the processes, and gives priority to the processes with lower accumulated progress. Experimental results on an Intel Xeon E5645 featuring six dual-threaded SMT cores show that the proposed scheduler improves both performance and fairness over two state-of-the-art schedulers and the Linux OS scheduler. Compared to Linux, unfairness is reduced to a half while still improving performance by 5.6 percent.