Changes between Version 2 and Version 3 of WorkingGroups/HPC
- Timestamp:
- 2014-11-03T15:12:25+01:00 (9 years ago)
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WorkingGroups/HPC
v2 v3 29 29 * define a simple configuration (with IO and complex geometry) that will serve as a proof of concept for validating the proposed approach for the future system. 30 30 31 == Some ideas...:[[BR]] == 32 A strong improvement of NEMO scalability is needed to be able to take advantage of the new machines. This means a deep review/rewrite of NEMO code at some point in the futur (beyond 5 years). At the same time, we already know that CMIP7 won't use an ocean model that has not been strongly tested and validated and will stick to a NEMO model close to the existing one. [[BR]] 33 This means that we need to: 34 1) keep improving the current structure of NEMO so it works quite efficiently for almost 10 more years (until the end of CMPI7). [[BR]] 35 2) start to work on a new structure that would be tested from year 5 and fully tested and validated for CMIP8 in about 10 years. [[BR]] 36 37 Based on this, we propose to divide the work according to 3 temporal window [[BR]] 38 39 '''0-3 years''': improvements with existing code: Do basic optimisation work: [[BR]] 40 1) reduce the number of communications: remove useless communications (a lot), do less and bigger communications (group communications, use large halo) [[BR]] 41 2) check code vectorization (AVX instructions for example) [[BR]] 42 3) reduce computations over halo (avoid systematic computation from 1 to jpi) [[BR]] 43 44 '''0-5 years''': improvements through the introduction of OpenMP: [[BR]] 45 work initialed by CMCC. 46 "Basic" implementation such as tiling may be efficient with many cores processors? 47 test different way to find new sources of parallelism. 48 49 '''beyond 5 years''': [[BR]] 50 GungHo or not GungHo, that is the question... 51 31 52 32 53 == Agenda:[[BR]] ==