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 Jens Gustedt INRIA RILLEpour la g rithmesALGO 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 Jens Gustedt INRIA RILLEpour la g rithmesALGO Stéphane Vialle

InterCell lowlevel ParXXL 4 Jens Gustedt Jens Gustedt INRIA RILLEpour la g rithmesALGO Stéphane Vialle Round trip time: > 0.13 s Synchronization Frequency: < 7.5 Hz Problem 1: Communication Latency

InterCell lowlevel ParXXL 5 Jens Gustedt Jens Gustedt INRIA RILLEpour la g rithmesALGO Stéphane Vialle Overruling Latency

InterCell lowlevel ParXXL 6 Jens Gustedt Jens Gustedt INRIA RILLEpour la g rithmesALGO Stéphane Vialle Problem 2: Data Management Access? Management?

InterCell lowlevel ParXXL 7 Jens Gustedt Jens Gustedt INRIA RILLEpour la g rithmesALGO Stéphane Vialle Delegation of responsibilities

InterCell lowlevel ParXXL 8 Jens Gustedt Jens Gustedt INRIA RILLEpour la g rithmesALGO Stéphane Vialle Isolation in welldefined parts Control Communication

InterCell lowlevel ParXXL 9 Jens Gustedt Jens Gustedt INRIA RILLEpour la g rithmesALGO 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 Jens Gustedt INRIA RILLEpour la g rithmesALGO 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 Jens Gustedt INRIA RILLEpour la g rithmesALGO 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 Jens Gustedt INRIA RILLEpour la g rithmesALGO 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 lines of code (sep 07 – sep 08)