Version 4 (modified by smasson, 9 years ago) (diff) |
---|
TOC(heading=NEMO_HPC,NEMO_HPC/*, depth=1)?
NEMO HPC
Working group leader (and responsible for wiki pages) : Sébastien Masson.
Members of the Working group:
- Sébastien Masson
- Italo Epicoco
- Silvia Mocavero
- Marie-Alice Foujols
- Jason Holt
- Gurvan Madec
- Mondher Chekki
Objectives:
- make short term recommendations for improving the performance of the existing system
- propose criteria for a taking decisions at Gateway 2025 regarding HPC.
- provide more detail on Gung-Ho (esp. regarding its implications for mesh discretization)
- identify other possible strategies and approaches for evolutions in the long term.
- 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.
Some ideas...:
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.
This means that we need to:
1) keep improving the current structure of NEMO so it works quite efficiently for almost 10 more years (until the end of CMPI7).
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.
Based on this, we propose to divide the work according to 3 temporal window
0-3 years: improvements with existing code: Do basic optimisation work:
1) reduce the number of communications: remove useless communications (a lot) 2) reduce the number of communications: do less and bigger communications (group communications, use large halo)
3) introduce asynchronous communications 3) check code vectorization (SIMD instructions)
0-5 years: improvements through the introduction of OpenMP:
work initialed by CMCC. "Basic" implementation such as tiling may be efficient with many cores processors? test different way to find new sources of parallelism.
OpenMP4, OpenACC?
beyond 5 years:
Agenda:
For the next 2 years, as a start, a workshop to be organized in 2015 on “NEMO in 2025 : routes toward multi-resolution approaches”.
Attachments (5)
- HPC_tasks_Masson.doc (37.5 KB) - added by timgraham 8 years ago.
-
NEMO_HPC_WG_June_2019_final.pdf
(388.1 KB) -
added by mikebell 5 years ago.
NEMO HPC WG objectives & activities June 2019
-
Stock_take_NEMO_HPC_WG_v0.3.pdf
(673.7 KB) -
added by mikebell 5 years ago.
NEMO HPC WG stock take (15 Jan 2019)
-
NEMO_HPC_WG_201901_stock_take.pdf
(335.1 KB) -
added by mikebell 5 years ago.
NEMO HPC WG stock take (power point presented at Developers Committee)
-
NEMO_HPC_WG_201901_stock_take.2.pdf
(335.1 KB) -
added by mikebell 5 years ago.
NEMO HPC WG stock take (power point presented at Developers Committee)
Download all attachments as: .zip