Tutorial: Application Porting with the DCAPI The Uppercase Application

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TutorialApplication Porting with the DC-APIThe
Uppercase Application

• Gabor Szmetanko
• University of Westminster

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Agenda

• BOINC Desktop Grid installation
• Application porting with the DC-API
• Introduction, sample application
• Client side
• Master side
• Application deployment in BOINC

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The sample application

• We will port a very simple application to the DG,
  the Uppercase application
• Processes a text file
• Makes all of the characters uppercase in the
  input file
• Writes out the result to a file

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Sample files
Input
Output
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Parallelisation

• We would like to make our application more
  efficient by parallelising it
• BOINC is based on the master-worker model
• Two applications master, worker
• The original problem has to be divided into
  independent subtasks
• The tasks of each application should be clearly
  identified

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The parallelisation algorithm1

• The text file can be divided into smaller chunks
• These chunks can be processed independently by
  different worker nodes
• The master application concatenates the processed
  chunks to create the final result
• A line of text can be used as the basic unit to
  produce the chunks

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The parallelisation algorithm2
Input
Master
Worker 3
Worker 1
Worker 2
Master
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What needs to be implemented?
Master side
Client side
The BOINC client fetches work units from the
server
Needs implementation
The client downloads the inputs and the
executables
Done by the user
The BOINC client starts the worker application
Done automatically
Validates the results
The worker application runs
Assimilates the results
The client uploads the results
Returns the outputs
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Outline of the tasks

• Tasks of the master
• application
• Read the input file
• Divide the text file into smaller chunks
• Create and submit work units
• Wait for the results
• Validation
• Assimilation (Concatenation)

• Tasks of the worker
• application
• Execution of a single work unit
• Make the characters uppercase in its own chunk
• Produce output for the subtask

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DC-API1

• Distributed Computing Application Programming
  Interface
• Allows easy implementation and deployment of
  distributed applications on multiple grid
  environments
• The DC-API was created by MTA SZTAKI
• We will use the DC-API to port the Uppercase
  application

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DC-API2

• Properties of a DC-API application
• Master-worker concept
• Work units are sequential applications
• No direct communication between clients

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Running the sequential version1

• Go to the folder of the sequential Uppercase
  application

• Compile the application

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Running the sequential version2

• Run the application

• The application reads the file in.txt and writes
  the results to out.txt. Check the contents of
  out.txt!