POD running slower with python 3.12.10 vs. 3.12.9

[erileydellaripa]

Bug Severity

• 1 = Minor problem that does not affect total framework functionality (e.g., computation error in a POD, problem with logging output, or an issue on a single system
• 2 = Major problem that affects overall functionality, but that does not occur for all users (e.g., problems installing the framework with a specific Conda version, a framework option that causes one or more PODs to fail, or missing/incompatible Python modules).
• 3 = Catastrophic problem that occurs frequently for multiple users and/or on multiple systems (e.g.,framework consistently fails to install on multiple systems, or one or more PODs continuously fails after running successfully)

Describe the bug
When I ran my POD on my fork back in February using python 3.12.9, the POD would take about 12 minutes to run. After merging the latest updates from NOAA-GFDL main, the POD now takes about an hour to run. I tried chunking my xarrays differently, which improved the wall time slightly, but the issue seems to be with plotting as there about 50 minutes between a netcdf file being saved and the two plots being generated.

Steps To Reproduce

• I rebased my branch to the latest updates on NOAA-GFDL main

• I recompiled the software package

• Ran my POD. Nothing was changed in the POD initially from the previous time I ran the POD and it only taking about 10 minutes to run.

• After the POD was taking too long to run, I aborted it and changed some chunking in my xarrays to try to alleviate the issue

• I ran the POD again and it took about an hour to complete

• I also ran some tests independent of the mdtf software package, but using the _MDTF_python3_base environment versus myenv, where myenv uses python 3.10.16. I've placed screen shots in a google drive folder of how the times to complete various steps of the POD compared using the two environments.

Environment
Describe the system environment:

• OS: MAC OS 10.15.7
• Conda version: 23.5.2
• branch name and link: https://github.com/erileydellaripa/MDTF-diagnostics/tree/feature/Pac_WWEs

Log information and/or terminal output
GitHub is not allowing me to attach any files. It keeps failing. I've but the files in a google drive folder.
https://drive.google.com/drive/folders/1A6S8rxFPCSKRqXoEUI4Xv6pwAaX9uN8D?usp=sharing

[wrongkindofdoctor]

@erileydellaripa Python's documentation states that only security fixes are applied to Python 3.12 at the current stage of version's lifecycle, so it's more likely that updates to one or more packages/dependencies applied prior to your most recent _MDTF_python3_base rebuild may be slowing the POD.

You can see a comparison of the old/new files here. xarray was updated from 2024.1.1 to 2025.1.2, and Dask was updated from 2024.1.1 to 2025.2.0. Changes in one or both packages would likely contribute to performance issues, so I suggest testing with xarray 2024.1.1 & dask 2025.2.0, and dask 2024.1.1 & xarray 2025.1.2 in the python3_base environment and your own environment to try and isolate the source of the issue.