Credit-HC： An I/O-friendly CPU Scheduler for Xen  

作　　者：XIA Yubin YANG Chun NIU Yan CHENG Xu 

机构地区：[1]Microprocessor Research and Development Center, Peking University, Beijing 100871, China [2]Shenzhen Graduate School of Peking University, Shenzhen 518055, China

出　　处：《Chinese Journal of Electronics》2010年第3期409-413,共5页电子学报（英文版）

摘　　要：Recent advances in virtualization technologies make the VM （Virtual machine） based server consolidation attractive for reducing cost and improving efficiency in enterprise computing. However, on a Xen-based platform, the I/O performance of a VM degrades significantly as the degree of consolidation increases, even if the VM is configured to have enough CPU share. This paper analyzes this phenomenon and identifies the reason as the mismatch between the CPU scheduler of Xen and its I/O architecture. We therefore present four enhancements for the CPU scheduler, including preempt-back, no-preemptlon of driver domain, block-bonus, and more fine-grained accounting. These enhancements are applied into our newly developed I/O-friendly CPU scheduler, namely Credit-HC （Credit-based high-consolidation-oriented） scheduler. The evaluation results show that with Credit-HC, one VM＇s I/O performance is nearly irrelevant to other domains, CPU workload, while the overhead is negligible. Moreover, the fairness of CPU share is kept as well.

关 键 词：Server consolidation I/O performance Virtual machine monitor Virtual machine scheduling. 

分 类 号：TP391[自动化与计算机技术—计算机应用技术] TP278[自动化与计算机技术—计算机科学与技术]