Reading forcing files on Curie is time-consuming

[dsolyga]

On Curie, ORCHIDEE takes too much time to read the time steps axis. The problem is proportional to the number of processors. On 96 processors, it takes almost 50% of the time calculation for one year.
You can find some figures :
here
I found the line in IOIPSL/flincom.f90 at the origin of the problem :

 iret = NF90_GET_VAR (fid,vid,vec_tmp,start=(/ 1 /),count=(/ ttm /))

There are two explanations :

• the lustre system used by TGCC is configured for "big" files. When some data are read into a netcdf file, 2Mo of memory is used by the system.
• Moreover, the array vec_tmp contains data which are not contiguous in the netcdf file (UNLIMITED/LIMITED attributes).

The solution consists to modify readdim2 in two places :

• comment the call to flinclo as the file is reopened after
• change memory allocation for itau as only the two first values are only read :

    ttm_part=2   ! Here only read the 2 first values of time axis
    ALLOCATE(itau(ttm_part))
  
    CALL flinopen &
  &  (filename, .FALSE., iim_full, jjm_full, llm_full, lon_full, lat_full, &
  &   lev_full, ttm_part, itau, date0, dt_force, force_id) 
  
  

  When we use this patch, the results are correct :

[dsolyga]

Correction applied. See revision[1060].