TaskVine executor: add parsl serialize module to default library context

[colinthomas-z80]

Description

This improves task throughput for taskvine serverless by caching the serialize module and base function definition in the library

Type of change

Choose which options apply, and delete the ones which do not apply.

• New feature

[benclifford]

This needs cctools 7.13.0 (because thats the first release that has hoisting_modules) but I noticed that Parsl CI is still on 7.8.0 so I think there isn't any test coverage for this change.

[benclifford]

I tried this out on my laptop with serverless mode turned on: a pytest run reduces from 116 seconds to 20 seconds. So it would be good for timing considerations to switch our CI taskvine test over to this mode, perhaps.

and

parsl-perf --time 20 --config parsl/tests/configs/taskvine_serverless.py

goes from
6 tasks/sec
to
140 tasks/sec

Importing parsl.serialize will (in usual Python) import parsl first which will in turn import a very large part of the parsl package tree - because parsl/__init__.py imports a lot for re-export - to get a "batteries included" style of import parsl.

So I propose that importing plain parsl rather than parsl.serialize should result in the same performance change - I tried that out on my laptop and the results appear to have about the same distribution (by eyeball).

I'm a little unclear what happens for user code that would benefit from this kind of pre-load for other modules.

[benclifford]

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