Fair Share CPU Scheduling is a CPU scheduling algorithm that allocates processing resources based on the needs of each task. The goal of Fair Share Scheduling is to provide each task with a fair allocation of processing time, while ensuring that the operating system meets its performance goals. Fair Share Scheduling is widely used in cloud computing, virtualized environments, and multi-user systems, where multiple tasks compete for processing resources.
The main idea behind Fair Share Scheduling is to divide the processing resources of the system into a set of virtual machines, each with its own processing capacity. Tasks are then assigned to virtual machines based on their processing needs, with each virtual machine receiving an equal share of the processing resources. This ensures that each task receives a fair allocation of processing time, while ensuring that the operating system meets its performance goals.
One of the key benefits of Fair Share Scheduling is that it provides fairness and equal allocation of resources. This ensures that each task receives an equal share of the processing time, regardless of the processing requirements of other tasks. This is important for multi-user systems, where multiple tasks compete for processing resources, as it ensures that each user receives an equal share of the processing time.
Another benefit of Fair Share Scheduling is that it provides predictability and stability. This means that the operating system can predict the processing requirements of each task and can allocate processing resources accordingly. This ensures that the operating system meets its performance goals and that tasks are executed in a predictable and stable manner.
In addition, Fair Share Scheduling is flexible and adaptable. This means that the operating system can adjust the allocation of processing resources in real-time based on the changing needs of the system. This allows the operating system to respond to changing workloads and to ensure that processing resources are used efficiently.
However, Fair Share Scheduling also has some disadvantages. One of the main disadvantages of Fair Share Scheduling is that it can result in low utilization of processing resources. This occurs when tasks are underutilized, resulting in processing resources being left unused. This can lead to decreased system performance and reduced efficiency.
Another disadvantage of Fair Share Scheduling is that it can result in low responsiveness. This occurs when tasks are unable to respond to changes in processing requirements, such as increased workloads or changes in system configuration. This can result in decreased system performance and reduced responsiveness.
To overcome these disadvantages, Fair Share Scheduling can be combined with other CPU scheduling algorithms, such as Earliest Deadline First (EDF) or Rate Monotonic Scheduling (RMS). EDF and RMS are real-time scheduling algorithms that prioritize tasks based on their deadlines or processing requirements, allowing the operating system to provide real-time services and to ensure that time-sensitive tasks are completed within their deadlines.
In conclusion, Fair Share CPU Scheduling is a CPU scheduling algorithm that allocates processing resources based on the needs of each task. Fair Share Scheduling provides fairness, predictability, stability, and flexibility, while ensuring that the operating system meets its performance goals. However, Fair Share Scheduling can also result in low utilization of processing resources and low responsiveness, which can be overcome by combining Fair Share Scheduling with other CPU scheduling algorithms. Fair Share Scheduling is an important tool for operating system designers, as it allows them to provide equal allocation of processing resources and to meet the performance goals of their systems.
