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gh-118392: Add note about random.random for multi thread app #118396

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corona10 merged 3 commits into from
Apr 30, 2024
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gh-118392: Add note about random.random for multi thread app #118396

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gh-118392: Add warning about random.random for multi thread app
corona10 Apr 29, 2024
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corona10 Apr 29, 2024
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Address code reivew
corona10 Apr 29, 2024
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4 changes: 4 additions & 0 deletions Doc/library/random.rst
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Expand Up @@ -294,6 +294,10 @@ be found in any statistics text.

Return the next random floating point number in the range ``0.0 <= X < 1.0``

.. warning::
Calling this function in the concurrent use can cause performance degradation.
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terryjreedy marked this conversation as resolved.
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Instead, Consider using :class:`Random` per thread.

@colesbury colesbury Apr 29, 2024

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Let's move this up to the module level, perhaps between the security warning and the "see also". The advice is not limited this function.

I think maybe a .. note:: is more appropriate. A red "warning" seems a bit severe to me.

For the text, something like:

The global random number generator and instances of :class:`Random` are thread-safe. However, 
in the free-threaded build, concurrent calls to the global generator or to the same instance of :class:`Random`
may encounter contention and poor performance. Consider using separate instances of :class:`Random`
per thread instead.

@terryjreedy terryjreedy Apr 29, 2024

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I agree. This replaces my comment.


.. function:: uniform(a, b)

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