CPU Scheduling Concepts Quiz

A process relinquishes control of the CPU voluntarily due to resource unavailability, like waiting for I/O operation. This is a natural pause to acquire needed resources.

The CPU forcefully takes control from a process, often due to a time limit or another process taking priority. The process is interrupted.

The proportion of time the CPU is actively engaged in executing instructions. It measures CPU utilization efficiency.

The rate at which processes are completed within a specific time frame. It indicates how effectively tasks are being processed.

The total time a process takes from submission to completion. It includes waiting, execution, and I/O time.

The amount of time a process spends queued, waiting for its turn to use the CPU. It reflects the efficiency of the scheduler.

The time taken for a process to start producing the first response after being submitted. It's how quickly the process starts showing results.

A scheduling algorithm that prioritizes jobs with the shortest estimated CPU burst time.

A parameter in the exponential average formula that determines the relative weight assigned to recent and past CPU burst history. It ranges from 0 to 1, where 0 gives no weight to recent history and 1 considers only the latest burst.

In the context of scheduling, the estimated time a process will take to execute its next CPU burst.

A type of SJF scheduling where the currently running process can be interrupted (preempted) if a new process arrives with a shorter estimated CPU burst time.

A type of SJF scheduling where the currently running process is allowed to complete its entire CPU burst before any other process gets the CPU, even if a shorter job arrives.

A scheduling algorithm where each process gets a fixed amount of CPU time called a 'time quantum'. If the process doesn't finish within its time quantum, it's preempted and placed back in the ready queue.

The fixed amount of CPU time allocated to each process in Round Robin scheduling.

The act of interrupting a running process before it completes its CPU burst and placing it back in the ready queue to allow another process to run.

The average waiting time of all processes in a scheduling algorithm.

The length of time a process needs to execute on the CPU.

The process that is currently using the CPU.

Each thread gets a dedicated LWP (Light-Weight Process), creating a 1-to-1 mapping between threads and LWPs, thus, eliminating thread contention issues and improving performance.

A system that manages the contention scope policy for threads, either using PTHREAD_SCOPE_PROCESS or PTHREAD_SCOPE_SYSTEM. This policy determines if multiple threads can run on a single LWP.

A library function to set or get the contention scope policy for a thread.

Each thread shares access to the same LWP, meaning multiple threads compete for execution on the same core.

A function that retrieves the current contention scope policy of a thread, setting an int* variable to the current value.

The degree of contention or competition among threads for access to resources like CPU cycles or locks.

A lightweight process (LWP). A virtual process that runs on a real CPU core, providing a scheduling entity for threads. LWPs provide thread management without requiring separate kernel processes.

A library function that allows you to set the scheduling attributes of a thread, including its contention scope policy.

The operating system decides which software thread to run on each processing core.

The core decides which hardware thread to run when multiple threads are vying for the same core.

Each processing core can only execute one hardware thread at a time, even with multiple hardware threads available.

A simple approach to level 2 scheduling where each thread gets an equal time slice on the core.

A scheduling strategy for dual-core Itanium processors where urgency values are used to prioritize threads.

Events that trigger thread switching in Itanium processors, such as time slices ending or interrupts.

The operating system can make more informed scheduling decisions if it knows about the sharing of processor resources.

The two levels of scheduling are not mutually exclusive. The OS can use information from level 2 scheduling to make better decisions at level 1.

A CPU scheduling algorithm that prioritizes processes with the shortest execution period (deadline). Processes with shorter periods are assigned higher priority, ensuring higher frequency execution.

The time it takes for a process to complete its execution and return to the ready state. It's the length of time from the start to the end of a cycle.

The maximum amount of time a process can run without interruption. It's the deadline for the process to complete its CPU burst.

The amount of CPU time needed for a process to complete its execution. It's how long a process takes to run its instructions.

The maximum CPU utilization that a system can achieve using rate-monotonic scheduling. The utilization is limited, meaning the CPU won't always be fully loaded.

A value that indicates the number of processes in a system. It's a measure of how many processes are running or waiting to run.

The maximum CPU utilization achievable with rate-monotonic scheduling decreases as the number of processes (N) increases. The more processes you have, the less CPU power is available for each process to complete on time.