A variation of the round-robin scheduler is the regressive round-robin scheduler.
This scheduler assigns
each process a time quantum and a priority. The initial value of a time quantum is 50 milliseconds. However,
every time a process has been allocated the CPU and uses its entire time quantum (does not block for I/O),
10 milliseconds is added to its time quantum, and its priority level is boosted. (The time quantum for a processcan be increased to a maximum of 100 milliseconds.)
When a process blocks before using its entire time
quantum, its time quantum is reduced by 5 milliseconds, but its priority remains the same.
What type of process (CPU-bound or I/O-bound) does the regressive round-robin scheduler favor? Explain.
Answer:
This scheduler would favor CPU-bound processes as they are rewarded with a longer time quantum as well as
priority boost whenever they consume an entire time quantum. This scheduler does not penalize I/O-bound
processes as they are likely to block for I/O before consuming their entire time quantum, but their priority
remains the same.