Compare process scheduling of Wnidows XP and Ubuntu operating.
system.
Answers
Answer:
Windows XP uses a quantum-based, preemptive priority scheduling algorithm. The scheduler was modified in Windows Vista to use the cycle counter register of modern processors to keep track of exactly how many CPU cycles a thread has executed, rather than just using an interval-timer interrupt routine.
Linux
From versions 2.6 to 2.6.23, the kernel used an O (1) scheduler. The Completely Fair Scheduler is the name of a task scheduler which was merged into the 2.6.23 release of the Linux kernel. It handles CPU resource allocation for executing processes, and aims to maximize overall CPU utilization while maximizing interactive performance. It uses that uses red-black trees instead of queues.
Two classes of processes:
real-time (soft deadlines)
timesharing algorithm
Normal process scheduling uses a prioritized, preemptive, credit-based policy:
Scheduler always chooses process with the most credits to run.
On each timer interrupt one credit is deducted until zero is reached at which time the process is preempted.
If no ready process then all credits for a process calculated as credits = credits/2 + priority.
This approach favors I/O bound processes which do not use up their credits when they run.
The Round Robin and FIFO scheduling algorithms are used to switch between real-time processes