Very slow builds on CI machine

[buhrmann]

Hi,
I'm curious about great differences in build times for a package of mine (using conda mambabuild), between my local machine (macOS Arm M1), and a CI machine.

The greatest time seems to be spend on "Reloading output folder" steps. E.g. locally:

...
17:39:42 > #12 0.973 Attempting to finalize metadata for grapy-core
17:39:42 > #12 0.973 INFO:conda_build.metadata:Attempting to finalize metadata for grapy-core
17:39:48 > #12 6.455 Reloading output folder: /opt/conda/conda-bld
17:39:48 > #12 6.497 Reloading output folder: /opt/conda/conda-bld
17:40:30 > #12 48.90 Reloading output folder: /opt/conda/conda-bld
17:40:30 > #12 49.11 BUILD START: ['grapy-core-0.1.0-py_16.tar.bz2']
17:40:30 > #12 49.11 Reloading output folder: /opt/conda/conda-bld
17:40:32 > #12 50.76
17:40:32 > #12 50.76 ## Package Plan ##
...

where 42s of the total build time of 2:40s is spend on a single reload step.

And In CI it's much worse:

Here, the same reload step takes a whopping 166s, i.e. almost 3 min. And the total build takes more than 7 min, instead of the 2:40s locally.

Do you have any experience with such differences depending on the machine/environment?