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The Organic Grid : Self Organizing Computation on a
Peer to Peer Network
Vikram Negi
Distributed Computing
• Internet Computing– Desktop Grids : Scalability
• SETI@HOME, FOLDING@HOME
• Globus
Comparison
Problem Focus
• Schedule Independent Identical subtasks of an Independent Task Application with data in one location – NCBI nucleotide nucleotide sequence
comparison with BLAST tool.
Approach
• Tree Based Adaptive approach– Machine configuration, connection bandwidths,
network topology (absent)– Start Friends Lists ( Build overlay on fly)– Biology inspired LALI Principle
• Positive feedback - Activation
• Negative feedback - Inhibition
Approach
• Initially recruit Friends List– Encourage close nodes v/s distant nodes– Child nodes give passive feedback to measure
effective performance.– Continuous on fly adaptation
Basic Design
• Computation Agent– Identifies a child machine.– Allocate a subtask(computational process) in
child machine(availability).
• Tree structure– Node seeks more subtasks from parent if free.– Node send results to parents
Design
• Maintenance of child lists– Seek a balanced tree– Rank active children on response times..– Maintain a list of potential children
• Restructuring of the Overlay Network– Maintain a tree– Highest throughput closest to root.– Push low throughput closer to leaves.
Design
• Size of Result Burst– To determine rank – Average over a observation
• Fault tolerance– Maintain list of ancestors– Maintain list of unfinished tasks
• Cycles in the Overlay Network– Check the list of ancestors.
Design
• Termination– Root informs all actual, potential and former
nodes.
• Self adjustment of task list size– High performance machine request more tasks
• Prefetching– Give time and number estimates of future tasks
to parents.
Experiment Set up
• 18 machine
• NCBI BLAST application
• Task : Match– 256KB(sequence) with 320 Data chunk 512KB
size – Subtask match each sequence to chunk
Results
The time required for code and the first subtask to arrive at different nodes.
Autonomic ?
Child Propagation
Burst Size
Higher Burst Size slows experiment
Prefetch – Initial Task Size
Ramp up: Time req for subtasks to reach every single nodeRunning Time increases for > 1 prefetch tasks
Self Adjustment
Number of Children
• Good Initial Configurations no affect on running times.
Discussion
• Autonomic ?
Can we learn from
• Self Organizing :– Bird fly, Fishes swim in pattern
• Biods : simulation
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