This prototype has been completed and the repository has been archived.

Objectives

• To determine the suitability of Python as the language of the domain layer that controls:
  • Data access and iteration (visibility data).
  • Management of in-memory data structures (image grid).
• It is accepted that Python will not be suitable for all processing (for example gridding), consequently, the memory and compute overheads must be measured when allowing access to Python-controlled memory in C++.

Results

Memo: https://www.dropbox.com/scl/fi/ppxzarl8rznh2gwrwsftt/DIP.pdf?rlkey=u4zadf4dcobccxkf68gfjd15f&dl=0

Slides: https://docs.google.com/presentation/d/1T7TmovYOi1zO8SUA2nR_Ce5aUiT7ENbK4KITfnbWm7M/edit?usp=sharing

Create a conda python environment using dip_env.yml

Compiling the shared library on Linux

• Go to domain_infrastructure_prototype/src/domain_infrastructure_prototype
• g++ -O3 -fno-semantic-interposition -Wall -Wextra -shared -std=c++17 -I/Path/to/Python/Environment/include -fpic /$(python3 -m pybind11 --includes) gridder/pybind11_wrapper.cpp gridder/single_cf_gridder.cpp data_io/zarr_reader.cpp -o lib/pybind11_wrapper$(python3-config --extension-suffix) -lzstd

Remember to change -I/Path/to/Python/Environment/include

Compiling binary on Linux

• Go to domain_infrastructure_prototype/src/domain_infrastructure_prototype
• g++ -O3 -std=c++17 -I/Path/to/Python/Environment/include main.cpp gridder/single_cf_gridder.cpp data_io/zarr_reader.cpp -o bin/cpp_gridder -lzstd

Examples of running the code

• python main_numba.py --vis_data_folder ngvla_sim.vis.zarr --image_size 1000 --n_time_chunks 3 --n_chan_chunks 1
• python main_pybind11.py --vis_data_folder ngvla_sim.vis.zarr --image_size 1000 --n_time_chunks 3 --n_chan_chunks 1 --set_grid true
• python main_pybind11.py --vis_data_folder ngvla_sim.vis.zarr --image_size 1000 --n_time_chunks 3 --n_chan_chunks 1 --set_grid false
• python main_pybind11_cpp_only.py --vis_data_folder ngvla_sim.vis.zarr --image_size 1000 --n_time_chunks 3 --n_chan_chunks 1
• ./bin/cpp_gridder ngvla_sim.vis.zarr 1000 3 1

Valgrind

To use valgrind add -g compiler flag.

Example of running valgrind:

• valgrind --tool=callgrind --simulate-cache=yes python main_pybind11_cpp_only.py --vis_data_folder ngvla_sim.vis.zarr --image_size 5000 --n_time_chunks 1 --n_chan_chunks 3 callgrind_annotate --auto=yes callgrind.out. > profile.txt

-fPIC info:

• https://stackoverflow.com/questions/15861759/how-much-overhead-can-the-fpic-flag-add
• https://akkadia.org/drepper/dsohowto.pdf
• https://cseweb.ucsd.edu/~gbournou/CSE131/the_inside_story_on_shared_libraries_and_dynamic_loading.pdf