Download Description of the projects

Service Scheduler in a
Trustworthy Web Server
Yinong Chen
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Assumptions
Use off-the-shelf client software
 Use .Net framework
 .Net framework cannot be modified
 Not use off-the-shelf web server,
e.g. MS IIS (Internet Information
Service)
 We will write a simple server
software
 We will write simple service agents

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Implementation Overview
Clients
off-the-shelf
Web Server
Service
Provider
Agents
Service
Agents
Service
Scheduler
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C# Multithreading in .Net Framework
Service Scheduler
requests from Service Provider
Distributor
QS1
QS2
QS3
QS2
Priority
queues
Service
Scheduler
Dispatcher
(service activator)
S1 S3 S2 S4
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.Net
Runtime
What Can Be Scheduled

Service Scheduling
Which service agent should be
activated?
 Will be implemented in the prototype


Task Scheduling
Which process (all tasks and agents in
the system) should be executed?
 Should be implemented in the
infrastructure (OS)
 Will not be implemented in the
prototype

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Implementation Consideration
Each task, agent, or object is a C#
thread
 Threads are organized in a hierarchy
 The main() will activate two threads:


Service Provider, which will activate:
• service agents

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Scheduler, which will activate
• distributor
• priority queue agents
• dispatcher, which will activate the selected
service agent
Dispatch Policies
Select the most critical service first;
 Dispatch the request with the highest
priority;
 Each service agent will start a
quantum timer at the beginning.
When timeout, the current process is
saved, put back into its queue, and
another request is dispatched

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