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InterCell foundations with ParXXL
Render Large Scale Computations Interactive
Jens Gustedt
INRIA Nancy – Grand Est
AlGorille
Stéphane Vialle
Supélec Metz campus
InterCell lowlevel ParXXL 2
Jens Gustedt INRIA
RILLEpour la g
rithmes ALGO
Stéphane Vialle
Goals
Provide a programming paradigm and an interface:Simplicity:
easy to use close to existing programming habits
Performance: competitive responsive easy to evaluate
Interoperability: close to known standards, heterogenity of computing material, OS, administrative domains
InterCell lowlevel ParXXL 3
Jens Gustedt INRIA
RILLEpour la g
rithmes ALGO
Stéphane Vialle
InterCell lowlevel ParXXL 4
Jens Gustedt INRIA
RILLEpour la g
rithmes ALGO
Stéphane Vialle
Round trip time:> 0.13 s
SynchronizationFrequency:< 7.5 Hz
Problem 1: Communication Latency
InterCell lowlevel ParXXL 5
Jens Gustedt INRIA
RILLEpour la g
rithmes ALGO
Stéphane Vialle
Overruling Latency
InterCell lowlevel ParXXL 6
Jens Gustedt INRIA
RILLEpour la g
rithmes ALGO
Stéphane Vialle
Problem 2: Data Management
Access?Access?
Management?Management?
InterCell lowlevel ParXXL 7
Jens Gustedt INRIA
RILLEpour la g
rithmes ALGO
Stéphane Vialle
Delegation of responsibilities
InterCell lowlevel ParXXL 8
Jens Gustedt INRIA
RILLEpour la g
rithmes ALGO
Stéphane Vialle
Isolation in welldefined partsControl Communication
InterCell lowlevel ParXXL 9
Jens Gustedt INRIA
RILLEpour la g
rithmes ALGO
Stéphane Vialle
Two commonly used paradigms
Message Passing
• Standardization (MPI)
• Efficiency (distributed env.)• Simplified Data Control
• Memory Blowup• Extra Copies
Shared Memory
• Standardization (pthread, shm_open)
• Latency Problems• Data Consistency Problems
• Efficiency (parallel machines)• Random Access during Computation
InterCell lowlevel ParXXL 10
Jens Gustedt INRIA
RILLEpour la g
rithmes ALGO
Stéphane Vialle
parXXL unifies these paradigms
Low Level• Computational Efficiency (distributed and / or parallel)• Simplified Data Control• Memory Efficiency (data size)• Transfer Efficiency
High Level• Abstraction for Cellular Computation• Implementation of commonly used Cell-Networks
InterCell lowlevel ParXXL 11
Jens Gustedt INRIA
RILLEpour la g
rithmes ALGO
Stéphane Vialle
parXXL achievements 2008
Low Level• Packaging and Portability• Code Stability:
• Size Up (fill whole InterCell cluster)• Robustness (long runs = transient failures)
• Transfer Efficiency:• Data collectors. Collect distinguished data from the cells• Mix communication models (shared memory, files & messages)
InterCell lowlevel ParXXL 12
Jens Gustedt INRIA
RILLEpour la g
rithmes ALGO
Stéphane Vialle
ParXXL achievements 2008, cont.
High Level• Cellular Computation:
• Find a compromise between synchronized and de-synchronized Cell-Computation
• Develop new modes of asynchronous computation (cont.)• Implementation of commonly used Cell-Networks:
• Optimize the parallel deployment (avoid scaling problems) (cont.)
... changed 40000 lines of code (sep 07 – sep 08)
