Steps Involved in Convoy Effect in Operating Systems
Steps are as following below:
- The I/O bound processes are first allocated CPU time. As they are less CPU intensive, they quickly get executed and goto I/O queues.
- Now, the CPU intensive process is allocated CPU time. As its burst time is high, it takes time to complete.
- While the CPU intensive process is being executed, the I/O bound processes complete their I/O operations and are moved back to ready queue.
- However, the I/O bound processes are made to wait as the CPU intensive process still hasn’t finished. This leads to I/O devices being idle.
- When the CPU intensive process gets over, it is sent to the I/O queue so that it can access an I/O device.
- Meanwhile, the I/O bound processes get their required CPU time and move back to I/O queue.
- However in Convoy Effect, they are made to wait because the CPU intensive process is still accessing an I/O device. As a result, the CPU is sitting idle now.
Convoy Effect in Operating Systems
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.