Load Balancing and Grid
Computing
David Finkel
Computer Science Department
Worcester Polytechnic Institute
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References
• “The Anatomy of the Grid”, Ian Foster, Carl Kesselman,
Steven Tuccke, International Journal of Supercomputer
Applications, 2001
• “A Performance Oriented Migration Framework for the
Grid”, Satish S. Vadhiyar and Jack J. Dongarra,
Proceedings of CCGrid 2003, Third IEEE/ACM
International Symposium on Cluster Computing and the
Grid
• Innumerable papers by PEDS members Finkel, Wills and
Finkel, and Claypool and Finkel, with additional coauthors.
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What is the Grid? (Foster et al paper)
• Distributed computing infrastructure for
advanced science and engineering
• Runs over the Internet, potentially worldwide
• Several approaches have emerged: Paper
discusses Globus Toolkit
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The Grid Concept
• Coordinated resource sharing and problem
solving in dynamic, multi-institutional
virtual organizations.
• Highly controlled, with resource providers
and consumers defining what is shared and
the conditions of sharing.
• Issues to address: Protocols, privacy,
security, costs, …
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Related approaches
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Application Service Providers
Storage Service Providers
CORBA
DCE
Volunteer Computing (SETI @ home,
Distriblets, SLINC)
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Fabric Layer
• Provides access and control to resources
• Resources: Computational, storage, network
• Enquiry functions: to determine
characteristics and state of a resource
• Management functions: Start, stop
computations, reserve bandwidth
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Collective Layer
• Protocols and services not associated with a
particular resource
– Directory services for discovery of resources
– Co-allocation, scheduling, brokering
– Monitoring the Virtual Organization for failure,
intrusion detection, etc.
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Load Sharing - Overview
• Transferring work from a heavily loaded
node to a lightly loaded node
• Purpose: To improve application
performance
• Transferring processes not suitable for finegrain parallelism
• Also known as: Load Balancing, Process
Migration.
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Load Sharing Issues
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Criteria for heavily-loaded, lightly loaded
Measuring load (policy, implementation)
Exchanging information about load, state
Which jobs to transfer
When to transfer (new processes only,
already-running processes)
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Load Sharing in the Grid
• “A Performance Oriented Migration
Framework for the Grid”, Vadhiyar and
Donngarra
• Part of the GrADS project – Grid
Application Development System – based at
Univ. of Tennessee and other institutions
• Designed for long-running computations
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Load Sharing in the Grid - 2
• Basic idea – the load sharing system can run a
performance model of a computation to estimate
running time and resource requirements.
• Application programmer is responsible for
providing performance model for the application,
and hooks to stop application, checkpoint state,
and re-start application.
• Based on MPI Programming Library, Globus
Toolkit
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Load Sharing in the Grid - 3
• Before application begins, Application
Manager runs performance model to predict
execution times, number of processors.
• Determines whether an appropriate set of
processors is available, schedules jobs
• Monitors process of application as it runs
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Load Sharing in the Grid - 4
• Load sharing can occur if
– Application progress is delayed
– Additional resources become available
• App Manager sends message to application
so it will
– Checkpoint
– Stop computation
• Re-start on new collection of nodes
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Research Directions
• Load sharing on the Grid:
– There’s a large body of pre-Grid research of
load balancing in distributed systems
– Can the results of this research be used to
design load balancing systems for the Grid
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Load Balancing and Grid
Computing
David Finkel
Computer Science Department
Worcester Polytechnic Institute
Computer Science Department
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