what is scheduler latency?

Question

This seems to be a basic question, but i couldn't find answer anywhere in googling it.

As Far As I Understand, scheduler latency is the time incurred in making the task runnable again. I mean, if there are 100 processes namely 1, 2, e.t.c, then they are executed let's say in order starting from 1. So the latency is the time that the process 1 is executed again. which means that the latency is the waiting time of the process as well as the waiting time of it when it is in runqueue ready to execute.

Or

i misunderstood whole point and sheduler latency is just nothing but the context switching time between the processes?

Answer 1

Scheduling latency is the time that the system is inproductive because of scheduling tasks. It is system latency incurred because it has to spend time scheduling.

Specifically it consists of 2 elements:

• The delay between a task waking up and actually running (the 'context switching time')
• Time spent making scheduler decisions (the actual job of the scheduler, which consumes resources that cannot be used by real tasks anymore)