PERF: Set the default threader to Pool

[thewtex]

Continue to enable TBB support, but change the default threader to Pool.

TBB can exhibit decreased performance in some cases, and it seems that more refinement is needed with the number of work units, etc.

See:

https://discourse.itk.org/t/8x-slower-registration-with-itk-elastix-python-api-vs-elastix-cli-minimal-reproducible-example/7736
InsightSoftwareConsortium/ITKElastix#391

This setting is consistent with the libitk conda-forge build configuration.

[blowekamp]

LGTM.

Also note that the Pool is the default threader from the new conda-forge native ITK python package ( but Elastix is not enabled there yet).

[N-Dekker]

💯 Cool, thanks Matt!

[N-Dekker]

I noticed that four different syntaxes are being used to pass a CMake option, depending on context and platform:

--config.setting=cmake.define.ITK_DEFAULT_THREADER:STRING=Pool \
-DITK_DEFAULT_THREADER:STRING=Pool \
"-DITK_DEFAULT_THREADER:STRING=Pool",
-DITK_DEFAULT_THREADER:STRING=Pool

Just wondering, would there be a way to share the code (or at least share the CMake options) between the platforms?

Not an issue, just something I'm wondering 🤓

[thewtex]

@N-Dekker there is refactoring as Python scripts that may provide more unification.

[N-Dekker]

@thewtex:

there is refactoring as Python scripts that may provide more unification.

• Cool! Do you mean PR Python Build System #302 (by @CavRiley)?

[thewtex]

Or some variant of it.

[CavRiley]

I can break that PR into more digestible chunks if that's preferred.

[thewtex]

@CavRiley yes, smaller steps will help!