Ch. 10 PPT Flashcards
What is a loosely coupled/distributed/clustered system?
One that has a collection of relatively autonomous systems, each with its own main memory and I/0
What is a functionally specialized processor?
There is a master processor that directs specialized processors
What is a tightly coupled multiprocessor?
One that consists of a set of processors that share main memory and are under the integrated control of an OS
What is independent parallelism?
There is no explicit synchronization among processes; processes are independent. Used in time-sharing systems
What is coarse/very coarse grained parallelism?
There os synchronization among processes, but at a very gross level.
What is medium grained parallelism?
A single application can effectively be implemented as a collection of threads within a single process. Requires coordination
What is fine grained parallelism?
A complex use of parallelism that transcends threads. It’s specialized and fragmented with many approaches
What are parallelism design issues?
The dispatching of a process, use of multiprogramming on individual processors, and the assignment of processes to processors.
What is bad of assignment of processes to processors?
One might be idle while another has a backlog
What is an approach to processes to processors?
Master/slave, or peers
What is a master?
Something that is responsible for scheduling
What is a slave?
Something that sends requests to the master
What is good about master/slave?
Simple and requires little enhancement to a uniprocessor OS
What is bad about master/slave?
The master failing brings down the whole system, master can bottleneck
What is peer architecture?
The kernel can execute on any processor and each processor does self scheduling. Can complicate the OS
What are the approaches to thread scheduling?
Load sharing, dedicated processor, dynamic scheduling, and gang scheduling
What is load sharing?
Processes are not assigned to a particular processor. Process switching can cause bottlenecking when switching threads
What is gang scheduling?
Simultaneous scheduling of the threads that make up a process
What is thread dedicated processor assignment?
All threads execute on the same processor for a particular process. There is no multiprogramming of processors
What is dynamic thread scheduling?
Changing the number of threads in the process periodically
What is cooperative resource sharing?
Threads have access to the same set of main memory locations
What is resource contention?
Threads compete for cache memory locations
What is a hard real time task?
One that must meet a deadline
What is a soft real time task?
One that has a deadline, but it is not mandatory. Scheduling will occur regardless
