CPU Scheduling Flashcards
A process under execution in the CPU that can be interrupted by other process.
Preemptive Scheduling
A process with CPU allocated to it can keep the CPU until it releases it by terminating or switching to waiting state.
Nonpreemptive Scheduling
The percentage of time the CPU is busy.
CPU Utilization
The number of process that complete their excution per time unit.
Throughput
The amount of time it takes a process to excute.
Turnaround Time
The amount of time the process spends in the ready queue.
Waiting Time
The amount of time it takes a process to produce its first response since it submitted a request.
Response Time
The processes are based on their arrival times FIFO.
First Come First Serve - FCFS
The process cannot be preempted until it completes its CPU Brust Time.
Nonpreemptive Shortest Job First - Nonpreemptive SFJ
A process is put on pause if another one with a Brust Time less than the Remaining Time of the currently executing process is requesting execution.
Preemptive Shortest Job First - SFJ OR Shortest Remaining Time First - SRTF
Each process gets a Quantum Time, after that time elapses (ends), the process is preempted and added to the end of the Ready Queue.
Round Robin - RR
Based on the Priority Number the process was assigned, it executes and cannot be preempted until it completes its CPU Brust Time.
Nonpreemptive Priority
Based on the Priority Number the process was assigned, it executes and can be preempted if a new process with a higher priority arrives.
Preemptive Prority
It is the most optimal amoung all the nonpreemptive algorithms.
Nonpreemptive SJF
It is the most optimal amoung all the preemtive algorithms.
Preemptive SJF (SRTF)
Both algorthims cannot be accuratly implemented due the fact that how long a job will run cannot be ever known for certain.
Nonpreemptive SFJ and Preemptive SFJ (SRTF)
Both algorthims become the same as the FIFO algorthim when the Brust Time of the jobs (processes) is almost equal.
Nonpreemptive SFJ and Preemptive SFJ (SRTF)
This algorthim could lead to starvation if many short jobs are requesting execution, large ones will almost never get the chance to excute.
Preemptive SFJ (SRTF)
The algorthim behaves similarly to FIFO algorthim when the Quantum Time is very long compared to their Brust Time.
RR
This algorthim has less average Response Time than FIFO algorthim when the jobs have Brust Times that are not very similar to one another.
RR
This algorthim could lead to starvation if many high priority jobs are requesting execution, low priority jobs will almost never get the chance to excute.
Priority
Has deparate queues, foreground and background, and each have their scheduling algorthim.
Ready Queue
Priority ranges from 1 to 99.
Real Time Proccess in Linux
Priority is always 0.
Normal Processes in Linux.
A value used to modify the Process Priority.
Nice Value
Root user can modify the process to have nice values that range from __ to __.
-20, 19
Other users can modify the process to have nice values that range from __ to __.
0, 19
