Parametric Design of Embedded Real-Time Systems

这项研究的目标是开发可扩展的、自动化的方法来设计高性能的嵌入式系统-特别是那些具有实时延迟和吞吐量要求的系统。在这样的系统中，计算流经异类交互组件，这些组件由本地资源调度器和驱动程序管理。因此，一个关键的设计问题是平衡和调整本地资源管理器，以便它们协作地满足全球端到端性能目标。该方法将端到端的约束参数转换为局部的(按组件的)约束，然后求解它们以获得最优的在线性能。具体地，该方法通过(1)提取沿所有数据路径的关键阶段的性能模型；(2)将每个组件的模型分层地分组为更大的系统级原型；以及(3)使用系统级模型来帮助校准本地资源管理策略。第(3)步称为“设计综合”。为了实现这一点，该方法依赖于离线算法来综合所有流水线阶段的最优CPU/IO带宽分配。综合后，通过仿真对解析估计进行校核。然后对系统进行集成，并通过在线基准测试进行重新检查。提出了两个验证该框架的参考应用：(1)大型雷达信号处理器的软件实现，运行在多个工作站集群上；(2)通过100Mbs分区以太网连接的视频服务器系统。

The goal of this research is to develop scalable, automated methods to design high-performance embedded systems - particularly those with real-time latency and throughput requirements. In such systems, computations flow through heterogeneous interacting components, which are managed by local resource-schedulers and drivers. Hence, a key design problem is that of balancing and tuning the local resource-managers, so that they collaboratively meet the global end-to-end performance objectives. The proposed approach involves parametrically transforming the end-to-end constraints into local (per-component) constraints, and then solving them for optimal on-line performance. Specifically, the method works by (1) extracting performance models for key stages along the all data paths; (2) hierarchically grouping the per- component models into larger system-level prototypes; and (3) using the system-level models to help calibrate the local resource management policies. Step (3) is called "design synthesis." To carry it out, the proposed method relies on off-line algorithms to synthesize optimal CPU/IO bandwidth allocations for all pipeline stages. After synthesis, the analytic estimates are checked via simulation. Then the system is integrated, and rechecked via on- line benchmarking. Two reference applications are proposed to validate this framework: (1) A software realization of a large- scale radar signal processor, to be run on several workstation- clusters; and (2) a video server system connected via 100Mbs partitioned Ethernet.