Earliest Due Date Algorithm for Task scheduling for cloud computing
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The document discusses the Earliest Due Date algorithm for task scheduling in cloud computing. It begins with an introduction to cloud computing and describes how it provides computing resources over the internet. It then provides an overview of task scheduling algorithms, including their purpose of assigning tasks to resources to optimize performance. The document focuses on the Earliest Due Date algorithm, which executes tasks based on the earliest deadline first. It provides an example of how EDD would schedule a set of tasks and discusses how EDD is optimal for real-time systems as it attempts to minimize maximum lateness. The document concludes by noting some advantages of EDD while also acknowledging it does not consider processing time.
Earliest Due Date Algorithm for Task scheduling for cloud computing
- 1. Earliest Due Date Algorithm for Task scheduling for cloud computing Presented by: Prakash Poudel
- 2. Introduction of Cloud Computing It is the delivery of different services through the Internet. It provides computing resources in the pool for users through the internet. These resources include tools and applications like data storage, servers, databases, networking, and software. From software and analytics to secure and safe data storage and networking resources, everything can be delivered via the cloud.
- 3. Tasks scheduling algorithms overview • The idea of task scheduling is to assign a set of tasks or processes to a set of computer processors considering, executing more than one process at a time and transmitting multiple flows simultaneously to achieve the optimal performance. • Tasks scheduling algorithms are defined as the mechanism used to select the resources to execute tasks to get less waiting and execution time. • Example of task scheduling algorithms are Shortest-Job-First (SJF), Round Robin (RR), Max-Min and Min-Min, FCFS (First-Come First-Serve) and RR and SRTF(Shortest- Remaining-Time-First). • Mainly Real time task Scheduling Algorithms are categories on primitive and non-primitive. • Tasks scheduling algorithms are defined as a set of rules and policies used to assign tasks to the suitable resources (CPU, memory, and bandwidth) to get the highest level possible of performance and resources utilization.
- 4. Advantages of task scheduling algorithms • Manage the memory and CPU • Improve fairness for all tasks. • Improving load balance. • Achieving high system throughput. • Increasing the number of successfully completed tasks.
- 5. Earliest Due Date ()Algorithm for Task scheduling • Earliest Due Date (EDD) is an optimal dynamic priority scheduling algorithm used in real-time systems. • EDD Execute Task with earliest due date (deadline) first. • It can be used for dynamic real-time scheduling. • Example: (1,10)(2,3)(3,5) • Schedule: (2,3)(3,5)(1,10) FACT: EDD is optimal • If EDF cann’t find a feasible schedule for a task set, then no other algorithm can, i.e. The task set is non schedulable.
- 6. Earliest Due Date ()Algorithm for Task scheduling ….. • EDD (Earliest Due Date). EDD sequencing rule is that “jobs are processed according to the due date • Example: Job Processing Due Date A 6 8 B 2 6 C 8 18 D 3 15 E 9 23
- 7. Solution Using EDD • Sequence of jobs executed as – B, A, D, C, E Jobs Flow Time Due Date Late ness IN OUT Earliness Tardiness B 0 2 6 -4 A 2 8 8 0 D 8 11 15 -4 C 11 19 18 +1 E 19 28 23 +5
- 8. Solution Using EDD 2 4 6 8 10 12 14 16 18 20 22 24 26 28 B A D C E
- 9. Solution Using EDD Total Flow Time = 2+8+11+19+28 = 68 Average Flow Time = 𝑇𝑜𝑡𝑎𝑙 𝐹𝑙𝑜𝑤 𝑡𝑖𝑚𝑒 𝑛𝑜.𝑜𝑓 𝑗𝑜𝑏𝑠 = 2+8+11+19+28 5 = 13.6 Average lateness = 𝐸𝑎𝑟𝑙𝑖𝑛𝑒𝑠𝑠+𝑡𝑎𝑟𝑑𝑖𝑛𝑒𝑠𝑠 𝑛𝑜.𝑜𝑓 𝑗𝑜𝑏𝑠 = 0−4−4+1+5 5 = 1.2 Average tardiness = 𝑡𝑎𝑟𝑑𝑖𝑛𝑒𝑠𝑠 𝑛𝑜.𝑜𝑓 𝑗𝑜𝑏𝑠 = 1+5 5 = 1.2 Average number of jobs = 𝑡𝑜𝑡𝑎𝑙 𝑓𝑙𝑜𝑤 𝑡𝑖𝑚𝑒 𝑡𝑜𝑡𝑎𝑙 𝑝𝑟𝑜𝑐𝑒𝑠𝑠𝑖𝑛𝑔 = 68 28 = 2.4
- 10. EDD: optimality • Assume that Ri is the finishing time (relative to the release time) of task i. Note that R means response time. Let Li = Ri-Di (the lateness for task i) • FACT: EDD is optimal with respect to minimizing the maximum lateness Lmax= MAXi(Li) (the general form of optimality of EDD) • Note that even a task set is non schedulable, EDD may minimize the maximal lateness (minimizes loss for soft tasks?)
- 11. EDD: Schedule ability test • If C1+C2...+Ck <=Dk for all k<=n for the schedule with nondescreasing ordering of deadlines, then the task set is schedulable • Response time for task i, Ri =C1+...+Ci
- 12. Advantage Earliest Due Date ()Algorithm • The earliest due date refers to the process or prioritizing jobs and segmenting according to their due dates. • If one has to look into the activities of production schedules then there are many parameters that are involved in the operations. • It helps to provide total details of the jobs scheduled and allows for making changes for the best outcome. • The problem with the earliest due date is that it does not take into account the time that is taken for processing.
- 13. Thank You