Asymmetric Multiprocessing vs. Symmetric Multiprocessing
There are two types of multiprocessing, Symmetric Multiprocessing and Asymmetric Multiprocessing. Multiprocessing system has more than one processor and they can execute multiple process simultaneously.
Deadline scheduler in Operating System
Deadline Scheduler is n I/O scheduler for the Linux kernel and guarantee a start service time for a request. Deadline Scheduler imposes deadlines on all I/O operations in order to prevent wanted requests. Two deadline read and write queues (basically sorted by their deadline) are maintained. For every new request, the scheduler selects which queue will serve for it. Read queues are given high priority than write queues because during read operations the processes usually get blocked.
Scheduling in Linux
The Linux scheduler is a priority based scheduler that schedules tasks based upon their static and dynamic priorities. When these priorities are combined they form a task’s goodness . Each time the Linux scheduler runs, every task on the run queue is examined and its goodness value is computed. The task with the highest goodness is chosen to run next.
CPU Scheduling in Operating Systems
A typical process involves both I/O time and CPU time. In a uni programming system like MS-DOS, time spent waiting for I/O is wasted and CPU is free during this time. In multi programming systems, one process can use CPU while another is waiting for I/O. This is possible only with process scheduling.
Preemptive and Non-Preemptive Scheduling
Preemptive scheduling is used when a process switches from running state to ready state or from waiting state to ready state. Preemptive scheduling is used when a process switches from running state to ready state or from waiting state to ready state.
Load Balancing
Load balancing is the process of distributing network traffic across multiple servers. This ensures no single server bears too much demand.
Real-Time Linux Kernel Scheduler
A real-time system is one that provides guaranteed system response times for events and transactions—that is, every operation is expected to be completed within a certain rigid time period. A system is classified as hard real-time if missed deadlines cause system failure and soft real-time if the system can tolerate some missed time constraints.
CPU Affinity
There are two types of CPU affinity. The first, soft affinity (also called natural affinity) is the tendency of the scheduler to try to keep processes on the same CPU as long as possible.
Completely Fair Scheduler (CFS) in Linux
Linux takes a modular approach to processor scheduling in that different algorithms can be used to schedule different process types. A scheduling class specifies which scheduling policy applies to which type of process.
Difference between Process and Thread
Process means any program is in execution. Thread is the segment of a process means a process can have multiple threads and these multiple threads are contained within a process.
Preemptive Scheduling
Almost all programs have some alternating cycle of CPU number crunching and waiting for I/O of some kind. In a simple system running a single process, the time spent waiting for I/O is wasted, and those CPU cycles are lost forever.