Processor Management Flashcards
What is processor scheduling?
When a process is created it is dispatched ( dunno if its right) then a scheduling decision is made that inserts a process in a priority queue
What are the scheduling algorithms?
First come first served
Round robin
Shortest process next
Multilevel queuing
How does the first come first served scheduling algorithm work?
Allocates a processor on basis of creation time(super computer)
How does the round robin scheduling algorithm work?
Shares the processor on base of equality
How does the shortest process next scheduling algorithm work?
Shares the processor on the basis of the shortest predicted execution time
shortest process next scheduling algorithm flaws ?
Short processes may take a lot of time all together
It depends on predicting execution but its difficult to predict input dependent processes
How does the multilevel queuing scheduling algorithm work?
Shares the processor on basis of execution history.
So first batch processes that need no input or output
Then interface processes that interact with the user
Then normal processes
What type of scheduling is best suited for a system oriented process and a user oriented process?
System oriented = first come first served
User oriented = shortest process next
What is load balancing and why is it necessary?
When an algorithm has a process to a different processor so it is less loaded.
It has become necessary for energy and power consumption
How does the Linux Completely Fair Scheduler (CFS) work?
The Linux Completely Fair Scheduler (CFS) determines the need of a process for more processor time based on the (little) processor time that it has already had.
The Linux scheduler attempts to keep a process on the same processor for as long as practical.
when is forced processor affinity useful?
forcing processor affinity with taskset is useful only in certain (licensed) applications
