On the design and implementation of a cache -aware soft real -time scheduler for multicore platforms
On the design and implementation of a cache -aware soft real -time scheduler for multicore platforms
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发表时间：
2009-08
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通讯作者：
J. Calandrino
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作者：
J. Calandrino
JOHN MICHAEL CALANDRINO：关于多核平台的缓存感知软实时调度程序的设计和实现（James H. Anderson指导下）实时系统是那些必须满足时间约束的系统。本文将多处理器实时系统的研究扩展到支持多核平台，即在单个芯片上包含多个处理核心。具体来说，本文的重点是在多核平台上设计一个缓存感知的实时调度程序，以降低共享缓存丢失率，提高共享缓存重用水平，同时必须满足时间约束。这个调度程序，在Linux中实现，采用：(1)实时工作负载的调度方法，满足时间约束，同时做出调度选择，减少共享缓存丢失率；(2)定量估算每个任务在执行过程中的缓存影响的分析器。实验表明，与其他方法相比，所提出的缓存感知调度器可以显著降低共享缓存丢失率。当提供了足够的硬件支持（主要以与缓存相关的性能监视特性的形式）时，这一点尤其正确。它还表明，与调度程序相关的开销与其他调度方法相当，因此开销不会抵消缓存丢失率的任何减少。最后，在涉及多媒体服务器工作负载的实验中，发现使用所提出的缓存感知调度器可以增加工作负载的大小。之前在多核平台的缓存感知调度领域的工作还没有解决对实时工作负载的支持问题，而在实时调度领域的工作也没有解决多核平台上的共享缓存问题。对于在多核平台上运行的实时工作负载，减少共享缓存丢失率可以导致相应的执行时间减少，这可能允许支持更大的实时工作负载或硬件
JOHN MICHAEL CALANDRINO: On the Design and Implementation of a Cache-Aware Soft Real-Time Scheduler for Multicore Platforms (Under the direction of James H. Anderson) Real-time systems are those for which timing constraints must be satisfied. In this dissertation, research on multiprocessor real-time systems is extended to support multicore platforms, which contain multiple processing cores on a single chip. Specifically, this dissertation focuses on designing a cache-aware real-time scheduler to reduce shared cache miss rates, and increase the level of shared cache reuse, on multicore platforms when timing constraints must be satisfied. This scheduler, implemented in Linux, employs: (1) a scheduling method for real-time workloads that satisfies timing constraints while making scheduling choices that reduce shared cache miss rates; and (2) a profiler that quantitatively approximates the cache impact of every task during its execution. In experiments, it is shown that the proposed cache-aware scheduler can result in significantly reduced shared cache miss rates over other approaches. This is especially true when sufficient hardware support is provided, primarily in the form of cache-related performance monitoring features. It is also shown that scheduler-related overheads are comparable to other scheduling approaches, and therefore overheads would not be expected to offset any reduction in cache miss rate. Finally, in experiments involving a multimedia server workload, it was found that the use of the proposed cache-aware scheduler allowed the size of the workload to be increased. Prior work in the area of cache-aware scheduling for multicore platforms has not addressed support for real-time workloads, and prior work in the area of real-time scheduling has not addressed shared caches on multicore platforms. For real-time workloads running on multicore platforms, a decrease in shared cache miss rates can result in a corresponding decrease in execution times, which may allow a larger real-time workload to be supported, or hardware