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Pants

Hi team, It is not clear to me the difference between rule_threads_core and process_execution_local_parallelism ? Could you please elaborate a little bit? And how to config them correctly.

Sure: The Pants engine runs by composing rule executions. A rule is an async python function (technically a coroutine) that runs in the pantsd engine process. Some rules do work by spawning new processes (e.g., to run a test, or a compiler, or a linter).

So those two options roughly control how many compute resources on your machine are dedicated to each of those needs.

For example, if I ask pants to run all rests, how those two configs would affect its performance?

the only way to answer that for your case is trial and error

without knowing what's in your tests, I can't evaluate how they compare to rule execution time

but very generally, tests tend to be process-heavy