PowerPoint Presentation On Load Sharing

Presentation On Load Sharing

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Load Sharing Presentation Transcript:

1. Base Papers
“Epoch load sharing” by Helen D. Kartza and Ralph C. Hilzer. “Effective Load Sharing on Heterogeneous Networks of Workstations” by Li Xiao, Xiaodong Zhang and Yanxia Qu.

2. Objectives
Define “Load Sharing”. What is Epoch Load Sharing? Define other load sharing strategies. Comparison. Examine Load Sharing in Heterogeneous Networks of Workstations. Compare all the techniques available.

3. Definition
Load balancing is to divide work evenly among the processors. Load sharing is to ensure that no processor remains idle when there are other heavily loaded processors in the system.

4. Algorithms
With sender-initiated algorithms, load-distribution activity is initiated when an over-loaded node (sender) tries to send a task to another under-loaded node (receiver). In receiver-initiated algorithms, load-distribution is initiated by an under-loaded node (receiver), when it requests a task from an over-loaded node (sender).

5. Scheduling Policies
Static Dynamic or Adaptive Probabilistic Deterministic

6. Static Policy
Scheduling policies that use information about the average behavior of the system and ignore the current state, are called static policies. The principle advantage of static policies is simplicity, since they do not require the maintenance and processing of system state information.

7. Static Policy
In the probabilistic case, the scheduling policy is described by state independent branching probabilities. Jobs are dispatched randomly to workstations with equal probability. In the deterministic case, routing decisions are based on system state, so jobs join the shortest of the all workstation queues.

8. Dynamic Policy
Policies that react to the system state are called adaptive or dynamic policies. Adaptive policies tend to be more complex, mainly because they require information on the system's current state when making transfer decisions. improve performance benefits over those achievable with static policies.

9. Dynamic Policy
When workstations become idle, jobs can migrate from heavily loaded workstation queues to idle workstations. Job Migration can be Receiver initiated or Sender initiated. It balances the job load and can improve overall system performance.

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