CPU Scheduling

Question 1

Basis for multiprogrammed OS which maximises CPU utilization

Answer 1

CPU scheduling

Question 2

Process execution which consists of a cycle of CPU execution and I/O wait

CPU burst (MAIN CONCERN) then I/O burst

Answer 2

CPU - I/O Burst Cycle

Question 3

This selects from among the processes in the ready queue and allocates one of them in the CPU

Answer 3

Short term scheduler

Question 4

CPU scheduling process takes place when a process

Answer 4

• switch from running to waiting
• switch from running to ready
• switch from waiting to ready
• terminate

(Nonpreemptive)

• consider access to shared data
• consider preemption while in kernel mode
• consider interrupts during crucial OS activities

(Preemptive)

Question 5

Gives control of the CPU to the process selected by the short term scheduler which involves

• switching contexts
• switching to user mode
• jumping to proper location in the user program to restart

Answer 5

Dispatcher module

Question 6

Time it takes for the dispatcher to stop one process and start another running

Answer 6

Dispatch latency

Question 7

Scheduling criteria which keeps the cpu busy at all times

Answer 7

CPU utilization

Question 8

Scheduling criteria which tracks the number of processes that complete their execution per time unit

Answer 8

Throughput

Question 9

Scheduling criteria which is the amount of time for a process to execute a particular process

Answer 9

Turnaround time

Question 10

Scheduling criteria which is the amount of time process has been waiting in the ready queue

Answer 10

Waiting time

Question 11

Scheduling criteria which is the amount it takes from when a request has been passed until the first response is produced

Answer 11

Response time

Question 12

A short process behind a long process

Answer 12

Convoy effect

Question 13

Ho to determine length of next cpu burst

Answer 13

Exponential averaging

Question 14

What is the problem of priority scheduling wherein LOW PRIORITY PROCESS MAY NEVER EXECUTE

Answer 14

Starvation

Question 15

Solution to the problem of priority scheduling wherein as time progresses, increase the prirority of the process

Answer 15

Aging

Question 16

A ready queue partitioned into ____ and ____

Answer 16

Multilevel queue

Foreground (interactive)
Background (batch)

Question 17

Scheduling algo of foreground and background

Answer 17

RR ; fcfs

Question 18

Scheduling between foreground and background

Answer 18

Fixed priority scheduling (foreground muna then background)
Time slice (80% foreground in rr & 20% background)

Question 19

Hierarchy of a multilevel queue scheduling

Answer 19

(Highest) system process
Interactive process
Interactive editing process
Batch process
Student process

Question 20

A process can move between queues in this type of queue where in processes cn be demoted or promoted to different queues

Answer 20

Multilevel feedback queue

Question 21

The thead library schedules USER LEVEL THREADS to run on lwp using PTHREAD_SCOPE _PROCESS

Answer 21

Process contention scope (local competition within process)

Question 22

Kernel thread scheduled ontonavailable cpu using PTHREAD_SCOPE_SYSTEM

Answer 22

System contention scope (competition among all threads)

Question 23

In a multiple processor scheduling, only one processor accesses the system data structures increasing the need for data sharing

Answer 23

Asymmetric multiprocessing

Question 24

In a multiple processor scheduling, each processor is self scheduled wherein all processes in common ready queue has its own private queue pr ready processes

Answer 24

Symmetric multiprocessing (smp)

Question 25

Types of processor affinity

Answer 25

Soft and hard affinity

Valiations incluing PROCESSOR SETS

Question 26

A way to keep efficiency of the CPU in SMP whrein trying to mainti=ain eben distributi9oon

Answer 26

Load balancing

Question 27

In smp, periodic tasks checks load on each processor and pushes task from overload cpu to other cou

Answer 27

Push migration

Question 28

In smp, idle processor pulls waiting task from busy processor

Answer 28

Pull migration

Question 29

A recent trend to place multiple processor cores on the same PHYSICAL CHIP which is FASTER AND CONSUMES LESS POWER

And multiple cores per thread also grows.
Execute another thread while memory stall is happening

Answer 29

Multicore processor

Question 30

A type of cpu scheduling where it can present obvious challenges

Answer 30

Real time cpu scheduling

Question 31

A type of realmtime cpu scheduling whrein there is no guarantee as tonwhen critical reak time process will be scheduled

Answer 31

Soft real time systems

Question 32

Task must be servicd by the deadline

Answer 32

Hard real time system

Question 33

A type of latency from ARRIVAL OF INTERRUPT to START OF ROUTINE that service the interrupt

Answer 33

Interrupt latency

Question 34

A type of latency which is the time for schedule to TAKE CURRENT PROCESS and SWITCH to another

Answer 34

Dispatch latency

Question 35

Priorities are assugned based in deadlines

Answer 35

Earliest deadline first (edf) scheduling

Question 36

How to select CPU scheduling algrithm for an os

Answer 36

Determine criteria and evaluate algorithm

Question 37

A type of ANALYTICAL EVAUATION wherein it takes a predetermined workloa and defines performance of each algorithm for that workload

Answer 37

Deterministic modeling