How does a multilevel feedback queue scheduler work? Group of answer choices It assigns a fixed time slice to each process It selects the shortest job to execute first It divides processes into multiple queues based on priority It prioritizes processes based on their arrival time
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It is a type of CPU scheduling algorithm that allows processes to move between different priority queues based on their behavior and requirements. Show more…
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Multiblocked queues: Multiple answers are allowed When the event occurs, the entire list of processes in the appropriate queue can be moved to the Blocked state. When the event occurs, the entire list of processes in all queues will be scanned. The Multiblocked queues scheme is a disadvantage for large OS. When the event occurs, the entire list of processes in the appropriate stack can be moved to the Ready state. When the event occurs, the entire list of processes in the appropriate LIFO can be moved to the Ready state. When the event occurs, the entire list of processes in the appropriate queue can be moved to the Running state. When the event occurs, the entire list of processes in the appropriate queue can be moved to the Ready state. The Multiblocked queues scheme is an advantage for large OS.
Sri K.
The existing scheduler in xv6 is a Round-Robin (RR) scheduler. Upon each timer interrupt, the interrupt handler switches to the kernel scheduler, which then selects the next runnable process to run. In this project, you will be putting a new scheduler - the modified Multi-Level Feedback Queue (mMLFQ) - into xv6. It has three queues: Qi, i = 1, 2, 3 with time quantum size 30 ms for Q1, 60 ms for Q2, and 90 ms for Q3. The key change here is we use a random Round-Robin policy for each queue. Instead of following a circular queue for each priority queue, we randomly pick a process from the queue. No priority boosting is required. The detailed policy is described as follows: Any new process will be inserted into Queue Q1. The scheduler will always randomly choose a process in the highest-priority non-empty queue in the order of Q1, Q2, and Q3. Any chosen process will be scheduled for the queue-corresponding quantum size or the remaining burst size if its remaining burst size is large enough. If the process has nothing remaining, the process will be removed from the queue after its execution. If the process is not done within this round, it shall be moved to the next lower-priority queue except for any process in Q3. Q3 runs a random Round-Robin with a time quantum size of 90 ms. If a process is not done within the assigned quantum size, it remains in Q3 competing for more rounds. 12. Testing For the testing, in the xv6 shell please run as follows: $ spin 10000000 &; spin 10000000 &; spin 10000000 & These three spins are executed in a single command line and run concurrently in the background. Please use cprintf() in the kernel as you did in P1 to print on the console the information for running spin processes as follows: Process spin 12 has consumed 10 ms in Q1 Process spin 12 has consumed 10 ms in Q1 Process spin 13 has consumed 10 ms in Q1 Process spin 13 has consumed 10 ms in Q1 Process spin 14 has consumed 10 ms in Q1 Process spin 14 has consumed 10 ms in Q1 ... Basically, at each timer interrupt, you print out the running process information. The information of the process ID and the process name, which are stored in the proc struct. Focus only on the spin processes.
Akash M.
Which type of computer activity would likely be assigned to the priority queue?• a. a background process that defragments the disk• b. sending email• c. a background process that releases unused memory blocks• d. mouse movement
Jen H.
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