Mastering Linux Kernel Development

Group scheduling

To ensure fairness when scheduling, CFS is designed to guarantee that every runnable process gets at least one run on the processor under a defined time duration, called the scheduling period. Within a scheduling period, CFS rudimentarily ensures fairness or, in other words, ensures that unfairness is kept at a minimum, as each process at least runs once. CFS divides the scheduling period into timeslices among all threads of execution to avoid process starvation; however, imagine a scenario where process A spawns 10 threads of execution and process B spawns 5 threads of execution: here CFS divides timeslices to all the threads equally, leading to process A and its spawned threads getting the maximum time and process B to ...