Transcript Phantom: Process Migration in Java Chris Serra Harit Modi

Phantom: Process Migration
in Java
Chris Serra
Harit Modi
Dept. of Computer Sciences
Motivation
• Process Migration
– Moving a running process to another host
• Applications
– load balancing
– fault tolerance
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Outline
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Motivation
Design Goals
Implementation
Future Work
Conclusions
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Design Goals
Phantom:
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Pre-emptable
heterogeneous
and
transparent
object migration
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Design Goals
• Heterogeneous
• Transparent
– code
– process
• Pre-emptable
• *** Use either prev slide or this one ***
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Spectrum of Possibilities
• Data Migration
• Process Migration
– homogeneous
– heterogeneous
• interpreted
• native
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Why Java?
• Heterogeneous “for free”
• Nice properties of language and VM
– type safe
– secure
– widely accepted
– JDK source public
• JVM Debugging (or -ger) Interface
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Runtime State Components
• data
– objects
• code
– bytecode
• execution state
– call stack
– operand stacks
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Migration Components
• Data
– object serialization
• Code
– class namespace non-uniform globally
+ Bytecode interpretation uniform
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Execution State
?
Per-method
operand stack
?
?
?
Call Stack
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Operand Stack
• Type information missing
– type verification at runtime
+ Use dataflow analysis to recreate
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Pointers
Objects
Call Stack
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Operand Stack - 2
• Object References
– Java objects - pointers
– multiple references
– address space machine-dependent
– “temporary” objects
+ encapsulate using Object Serialization
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Object Serialization
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Native Methods
• <Figure about When we can
checkpoint>
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Future Work
• Checkpointing Policies
• External References
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Conclusions
• Phantom
– pre-emptable
– heterogeneous
– transparent
– minimal modifications to JDK
• 739
+A
–F
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