Nov 28, 2023 · The Convoy Effect is a phenomenon associated with the First Come First Serve (FCFS) algorithm, in which the whole Operating System slows down due to a few slow processes. What is the Convoy Effect?

What is the convoy effect? Which algorithms have the best turnaround/response/wait time on average? Do preemptive algorithms do better on average response time compared to non preemptive?

Preemption can interact with synchronization in a multiprocessor context to create another nasty effect - the convoy effect. One thread acquires the lock, then suspends. Other threads come along, and need to acquire the lock to perform their operations.

CPU utilization – keep the CPU as busy as possible Throughput – # of processes that complete their execution per time unit Turnaround time – amount of time to execute a particular process Waiting time – amount of time a process has been waiting in the ready queue Response time – amount of time it takes from when a request was submitted until the first response is

What if one process is CPU bound and one is I/O bound? Should a new “job” be “initiated,” or should it be held? what might cause you to make a “hold” decision? Should a running program be temporarily marked as non-runnable (e.g., swapped out)? Which thread should be given the CPU next? For how long?

Back to FCFS: the convoy effect Definition A number of relatively-short potential consumers of a resource get queued behind a heavyweight resource consumer Consequences • CPU bound jobs will hold CPU until exit or I/O (but I/O rare for CPU-bound threads) • Long period with CPU held and no I/O request issued • Poor I/O device utilization ...

May 27, 2019 · Is the only difference between starvation and convoy effect that convoy effect is mainly defined on FCFS scheduling algorithms and starvation is on priority based scheduling? I researched on both effects but couldn't find a comparison.

Oct 7, 2017 · In books, I have read that FCFS suffers from convoy effect. I think that even SJF and priority (both preemptive and non preemptive) can suffer from convoy effect. In SJF, if a process with large burst time arrives first then no other process can preempt it …

Shortest Job First minimizes the average waiting time. If the system is preemptive then it minimizes the waiting time compared to other algorithms, the same goes for non-preemptive systems.

Jul 4, 2022 · Convoy Effect is phenomenon associated with the First Come First Serve (FCFS) algorithm, in which the whole Operating System slows down due to few slow processes. FCFS algorithm is non-preemptive in nature, that is, once CPU time has been allocated to a process, other processes can get CPU time only after the current process has finished.