Performance of NEMO 3.1

[ebehrens]

NEMO 3.1 on a NEC SX9 has half of the performance compared to NEMO 2.3. This can be attributed to the communication along the north-fold boundary condition. We have performed the following test:

1. ORCA05 on 4x1 PE under NEMO 2.3
2. ORCA05 on 4x1 PE under NEMO 3.1 (with IOF)
3. ORCA05 on 4x1 PE under NEMO 3.1 jperio=1 (with IOF)

[ebehrens]

Ftrace output for performed Experiments

[rblod]

HI

• it would be nice to have the global MPI information for both run with NEMO_3.1 too
  
• running 3.1 without IOF could be nice also to clarify the situation
  
• finally on NEC computers we use to run in cutting only along latitude, both for vectorization and to get rid of the north fold condition

Rachid

[ebehrens]

Replying to rblod:

HI

• it would be nice to have the global MPI information for both run with NEMO_3.1 too
  
• running 3.1 without IOF could be nice also to clarify the situation
  
• finally on NEC computers we use to run in cutting only along latitude, both for vectorization and to get rid of the north fold condition

Rachid

Hi

• MPI INFOS see attachments
• comparison between IOF and offline are under way

Erik

[ebehrens]

Hi

-concerning "cutting only along latitude" (1x4) and IOF (extra halos) we have problems, and will submit a new separate ticket after proofing results

Erik

[rblod]

Hi

I just noticed in a previous mail from Markus than he was using noopt_ieee option for compilation. If it is the case in your benchmark, this option shouldn't be in use and can slow down drastically the code.

Rachid

[andmirek]

In 10659:

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[andmirek]

In 10660:

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