Use multiprocessing start_method "spawn"
#4305
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Quoting from https://docs.python.org/3/library/multiprocessing.html#contexts-and-start-methods * fork ... Note that safely forking a multithreaded process is problematic. Available on Unix only. The default on Unix. The idea to try `"spawn"` is the result of deadlock debugging. After reviewing tracebacks @jbms wrote: > This actually looks like a general fork thread-safety issues, not related to pybind11 > Using fork in a multithreaded program is generally not safe
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Works! That's one way to get rid of the deadlocks (hoping this will do the trick). But I'll try "forkserver", too, in another PR. |
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Alternative to PR pybind#4305
This was referenced Nov 1, 2022
…similar to pybind#4306, the only difference between the two PRs is the `"spawn"` vs `"forkserver"` argument).
rwgk
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Alternative to PR pybind#4305
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* Use `multiprocessing` `start_method` `"forkserver"` Alternative to PR #4305 * Add link to comment under PR #4105 * Unconditionally `pytest.skip("DEADLOCK")` for PyPy Windows * Remove `SKIP_IF_DEADLOCK` entirely, for simplicity. Hopefully this PR will resolve the deadlocks for good. * Add "In a nutshell" comment, in response to request by @EricCousineau-TRI
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This PR was made obsolete by #4306. |
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Description
Quoting from
https://docs.python.org/3/library/multiprocessing.html#contexts-and-start-methods
fork
... Note that safely forking a multithreaded process is problematic.
Available on Unix only. The default on Unix.
The idea to try
"spawn"is the result of deadlock debugging. After reviewing tracebacks @jbms wrote:Suggested changelog entry: