Week 11 Flashcards
1
Q
Homogeneous Processors
A
- Within a multiprocessor
2
Q
Asymmetric multiprocessing
A
- only one processor accesses the system data structures, alleviating the need for data sharing
3
Q
What is Symmetric multiprocessing
A
- each processor is self-scheduling, all processes in common ready queue, or each has its own private queue of ready processes
4
Q
What is a Processor Affinity
A
- process has affinity for processor on which it is currently running.
Soft or hard affinity
5
Q
if we are using a Symmetric multiprocessor we need to keep all CPUS loaded for efficiency. What does this consist of?
A
- Load balancing attempts to keep the workload evenly distributed
- Push migration: Periodic task checks load on each processor and if found pushes task from overloaded CPU to other CPU’s
- Pull Migration: Idle processors pulls waiting task from busy processor
6
Q
What is a soft real-time system
A
- No guarantee as to when critical real-time process will be schedules
7
Q
What is a Hard real-time System
A
- Task must be serviced by it’s deadline
8
Q
What is Rate Montonic Scheduling?
A
- A priority is assigned based on the inverse of its period.
Shorter periods = higher priority
Longer periods = lower priority
9
Q
What is Earliest Deadline First Scheduling?
A
Priorities are assigned according to deadlines. The earlier the deadline the higher the priority
10
Q
Littles law
A
- In steady state, processes leaving queue must equal processes arriving
