操作系统Chapter10_OS多处理器调度和实时调度.ppt

Multiprocessor and Real-Time Scheduling (多处理器调度和实时调度) Chapter 10 10.1 Multiprocessor Scheduling -Classifications of Multiprocessor Systems Multiprocessor systems : 包含两个或更多处理器的计算机系统 Loosely coupled or distributed multiprocessor, or cluster (集群系统) Each processor has its own memory and I/O channels Functionally specialized processors (Master Slave) Such as I/O processor Controlled by a master processor Tightly coupled multiprocessing(紧密耦合) Processors share main memory Controlled by operating system 执行机 10.1 Multiprocessor Scheduling -10.1.1 Parallelism Independent Parallelism Coarse and Very Coarse-Grained Parallelism Medium-Grained Parallelism Fine-Grained Parallelism Independent Parallelism Separate application or job No synchronization among processes Example is time-sharing system Coarse and Very Coarse-Grained Parallelism Synchronization among processes at a very gross level Good for concurrent processes running on a multiprogrammed uniprocessor Can by supported on a multiprocessor with little change Medium-Grained Parallelism Single application is a collection of threads Threads usually interact frequently Fine-Grained Parallelism Highly parallel applications Specialized and fragmented area 10.1 Multiprocessor Scheduling -10.1.2 Scheduling Assignment of processes to processors Use of multiprogramming on individual processors Actual dispatching of a process Assignment of Processes to Processors Treat processors as a pooled resource and assign process to processors on demand Permanently assign process to a processor Dedicate short-term queue for each processor Processor could be idle while another processor has a backlog Assignment of Processes to Processors Global queue Schedule to any available processor Master/slave architecture Key kernel functions always run on a particular processor Master is responsible for scheduling Slave sends service request to the master Disadvantages Failure of master brings down whole system Master can become a performa