@@ -35,90 +36,92 @@ The model is implemented in Fortran 90, with pre-processing (C-pre-processor). I
```
./make_xios --arch local
```
Files for the PRACE Tier-0 systems are available under [architecture_files](architecture_files) folder.
Note that XIOS requires `Netcdf4`. Please load the appropriate `HDF5` and `NetCDF4` modules. You might have to change the path in the configuration file.
Note that XIOS requires `Netcdf4`. Please load the appropriate `HDF5` and `NetCDF4` modules. If path to these models are not loaded, you might have to change the path in the configuration file.
### Building NEMO
1. Download the XIOS source code:
```
svn co https://forge.ipsl.jussieu.fr/nemo/svn/NEMO/releases/release-4.0
```
2. Copy and setup the appropriate architecture file in the arch folder. The following changes are recommended:
2. Copy and setup the appropriate architecture file in the arch folder. Files for the PRACE Tier-0 systems are available under [architecture_files](architecture_files) folder. The following changes are recommended for the GNU compilers:
```
a. add the `-lnetcdff` and `-lstdc++` flags to NetCDF flags
b. using `mpif90` which is a MPI binding of `gfortran-4.9`
c. add `-cpp` and `-ffree-line-length-none` to Fortran flags
d. swap out `gmake` with `make`
```
3. Then build the executable with the following command
The GYRE configuration is set through the `namelist_cfg` file. The horizontal resolution is determined by setting `jp_cfg` as follows:
The GYRE configuration is set through the `namelist_cfg` file. The horizontal resolution is determined by setting `nn_GYRE` as follows:
```
Jpiglo = 30 × jp_cfg + 2
Jpjglo = 20 × jp_cfg + 2
Jpiglo = 30 × nn_GYRE + 2
Jpjglo = 20 × nn_GYRE + 2
```
In this configuration, we use a default value of 30 ocean levels, depicted by `jpk=31`. The GYRE configuration is an ideal case for benchmark tests as it is very simple to increase the resolution and perform both weak and strong scalability experiment using the same input files. We use two configurations as follows:
In this configuration, we use a default value of 30 ocean levels, depicted by `jpkglo=31`. The GYRE configuration is an ideal case for benchmark tests as it is very simple to increase the resolution and perform both weak and strong scalability experiment using the same input files. We use two configurations as follows:
Test Case A:
```
jp_cfg = 128 suitable up to 1000 cores
Number of Days: 20
Number of Time steps: 1440
nn_GYRE = 48 suitable up to 1000 cores
Number of Time steps: 101
Time step size: 20 mins
Number of seconds per time step: 1200
```
Test Case B:
```
jp_cfg = 256 suitable up to 20,000 cores.
Number of Days (real): 80
Number of time step: 4320
nn_GYRE = 192 suitable up to 20,000 cores.
Number of time step: 101
Time step size(real): 20 mins
Number of seconds per time step: 1200
```
We performed scalability test on 512 cores and 1024 cores for test case A. We performed scalability test for 4096 cores, 8192 cores and 16384 cores for test case B.
Both these test cases can give us quite good understanding of node performance and interconnect behavior.
We switch off the generation of mesh files by setting the `flag nn_mesh = 0` in the `namelist_ref` file. Also `using_server = false` is defined in `io_server` file.
<!--We switch off the generation of mesh files by setting the `flag nn_mesh = 0` in the `namelist_ref` file.
Also `using_server = false` is defined in `io_server` file.-->
We report the performance in step time which is the total computational time averaged over the number of time steps for different test cases.
This helps us to compare systems in a standard manner across all combinations of system architectures.
