Add load/save benchmarks

[stephenworsley]

Add benchmarks for the functions esmf_regrid.experimental.io.save_redridder and esmf_regrid.experimental.io.l_roadedridder.

[codecov]

Codecov Report

Merging #132 (b4763b8) into unstructured_scheme (0484f41) will decrease coverage by 0.00%.
The diff coverage is 100.00%.

@@                   Coverage Diff                   @@
##           unstructured_scheme     #132      +/-   ##
=======================================================
- Coverage                99.53%   99.53%   -0.01%     
=======================================================
  Files                       27       27              
  Lines                     1717     1715       -2     
=======================================================
- Hits                      1709     1707       -2     
  Misses                       8        8              

Impacted Files	Coverage Δ
.../tests/unit/experimental/io/test_round_tripping.py	100.00% <100.00%> (ø)
...ntal/unstructured_scheme/test__mesh_to_MeshInfo.py	100.00% <100.00%> (ø)

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[stephenworsley]

For the record, when the scalability benchmarks are run locally I get the following results:

[ 85.29%] ··· long.esmf_regridder.PrepareScalabilityGridToMesh.time_load                                                                        ok
[ 85.29%] ··· ============ ==========
               grid width            
              ------------ ----------
                   50       89.7±4ms 
                  100       98.3±7ms 
                  200       101±5ms  
                  400       119±5ms  
                  600       158±7ms  
                  800       192±10ms 
              ============ ==========

[ 88.24%] ··· long.esmf_regridder.PrepareScalabilityGridToMesh.time_prepare                                                                     ok
[ 88.24%] ··· ============ ============
               grid width              
              ------------ ------------
                   50        166±5ms   
                  100        593±30ms  
                  200       2.69±0.07s 
                  400       11.8±0.09s 
                  600       28.1±0.6s  
                  800       50.2±0.2s  
              ============ ============

[ 91.18%] ··· long.esmf_regridder.PrepareScalabilityGridToMesh.time_save                                                                        ok
[ 91.18%] ··· ============ ==========
               grid width            
              ------------ ----------
                   50       40.3±5ms 
                  100       45.1±5ms 
                  200       71.6±4ms 
                  400       140±4ms  
                  600       250±7ms  
                  800       447±10ms 
              ============ ==========

[ 94.12%] ··· long.esmf_regridder.PrepareScalabilityMeshToGrid.time_load                                                                        ok
[ 94.12%] ··· ============ ==========
               grid width            
              ------------ ----------
                   50       103±10ms 
                  100       102±10ms 
                  200       102±4ms  
                  400       122±8ms  
                  600       152±6ms  
                  800       212±10ms 
              ============ ==========

[ 97.06%] ··· long.esmf_regridder.PrepareScalabilityMeshToGrid.time_prepare                                                                     ok
[ 97.06%] ··· ============ ============
               grid width              
              ------------ ------------
                   50        217±10ms  
                  100        725±50ms  
                  200       3.14±0.2s  
                  400        14.4±1s   
                  600        30.7±1s   
                  800       1.06±0.01m 
              ============ ============

[100.00%] ··· long.esmf_regridder.PrepareScalabilityMeshToGrid.time_save                                                                        ok
[100.00%] ··· ============ ==========
               grid width            
              ------------ ----------
                   50       44.8±3ms 
                  100       56.9±4ms 
                  200       78.8±5ms 
                  400       160±10ms 
                  600       278±10ms 
                  800       484±30ms 
              ============ ==========

In the process, about 195MB of files are generated.

[trexfeathers]

Thanks @stephenworsley.

I'm pretty concerned about benchmark run time now - 14mins is a long time. My suggestion about parameterisation might help somewhat. Given other demands I think we're going to be forced to roll with it, but we shouldn't add any further benchmarks after this without reconsidering the efficiency of what we have (either by making existing ones smaller, or perhaps looking at GitHub Actions/caching).

The meat of this PR makes sense. My suggestions are mainly to improve efficiency/readability.

[trexfeathers]

Top work @stephenworsley 🥇