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