Collaborative Research: Algorithms Design and Systems Implementation to Improve Buffer Management for I/O Data Accesses

尽管处理器周期、内存大小和磁盘容量都变得越来越丰富，但是在处理数据密集型应用程序的系统支持方面仍然存在一个严重的缺陷，即硬盘访问的长延迟（通过获取请求数据的第一个字节的时间来衡量）。这种延迟改进明显落后于其他系统组件的改进，包括磁盘峰值带宽。为了解决这一关键问题，研究人员将开发新的高效缓冲缓存管理系统，以适应急剧的技术变化和具有复杂访问模式的数据密集型应用程序的高需求。为了使内存缓冲区成为应用程序请求和磁盘提供的服务之间真正有效的代理，研究人员将利用内存缓冲区中的缓存和预取机制，通过最小化昂贵的磁盘访问的成本（能量和时间）来提高应用程序感知到的有效I/O系统性能。将磁盘布局信息直接放在缓冲区管理的地图上，有效地整合时空位置，是本研究的独特之处。调查人员将设计并实现一个系统基础设施，分析和利用磁盘上的数据布局信息。有了这个关键的系统支持，研究人员将进一步设计和实现双侧感知存储器缓冲管理算法，以适应程序侧和磁盘侧显示的特性。

Although processor cycles, memory size, and disk capacity all become increasingly abundant, there is still a serious deficiency in the system support for handling data-intensive applications, which is the long latency of hard disk accesses, measured by the time to get the first byte of requested data. This latency improvement has significantly lagged behind other system component improvement, including disk peak bandwidth. To address this critical issue, the investigators will develop new and efficient buffer cache management systems that adapt to the dramatic technology changes and the high demand of data-intensive applications with complicated access patterns. Aiming at making the memory buffer as a truly effective agent between the requests from applications and services provided by disks, the investigators will leverage the cache and prefetch mechanisms in the memory buffer to improve effective I/O system performance, perceived by applications, by minimizing the cost (both energy and time) of expensive disk accesses. A unique approach to be adopted in the research is to put the disk layout information directly on the map of buffer management and effectively integrate both temporal and spatial localities. The investigators will design and implement a system infrastructure that analyzes and exploits data layout information on disks. With this critical system support, the investigators will further design and implement dual-side-aware memory buffer management algorithms that adapt to characteristics exhibited at both programs' side and disks' side.