Changes between Version 3 and Version 4 of 2020WP/HPC-07_mocavero_mpi3


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Timestamp:
2020-10-04T12:09:49+02:00 (4 months ago)
Author:
francesca
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  • 2020WP/HPC-07_mocavero_mpi3

    v3 v4  
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    39 Step 1: alignment of the dev_r11470_HPC_12_mpi3 branch with the new trunk\\ 
     39Step 1: alignment of the dev_r13296_HPC-07_mocavero_mpi3 branch with the new trunk (after July merge party) (done)\\ 
    4040 
    41 Step 2: integration of graph topology to allow each process to exchange halo with diagonal processes (when 9-point stencil is needed) or with non-neighbours processes (when land domain exclusion is activated or north fold has to be handled)\\ 
     41Step 2: integration of graph topology to support halo exchange for both 5-points (when exchange with only north, south, east and west processes is enough to preserve data dependency) and 9-points stencil (when exchange with diagonal processes is needed) computation. Land domains exclusion is also handled due to the flexibility of graph topology. A parameter in lbc_lnk mpi3 routine call allows to choose between 5-points or 9-points exchange (done)\\ 
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    43 Step 3: replacement of point-to-point communications with collective ones within the NEMO code\\ 
     43Step 3: add lbc_lnk mpi3 in traadv_fct.F90 (5-points stencil) and icedyn_rhg_evp.F90 (9-points stencil) files to perform comparability tests. Sette tests will be executed, also activating land domain exclusion\\ 
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     45Step 4: perform performance tests to evaluate the gain in both 5-points and 9-points stencil (done)\\ 
    4546 
     47Step 5: replacement of point-to-point communications with collective ones within the NEMO code. The choice between 5-points and 9-points exchange requires a data dependency analysis. The replacement will be performed in three steps:\\ 
     48 
     49     step 5.1: all the lbc_lnk will be replaced with 9-points mpi3 exchange (a key_mpi3 will be introduced to preserve the old point-to-point exchange version to be used on architectures where MPI3 is not supported or it does not provide a performance gain) (ready for December merge party)\\ 
     50     step 5.2: 5-points stencil exchange is introduced when data dependency is satisfied without diagonal exchange (in 2021)\\ 
     51     step 5.3: key_mpi3 will be removed (when the ST will confirm that implementation is more performant) \\ 
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