Issue #4751: hashlib now releases the GIL when hashing large buffers
(with a hardwired threshold of 2048 bytes), allowing better parallelization
on multi-CPU systems. Contributed by Lukas Lueg (ebfe) and Victor Stinner.
diff --git a/Doc/library/hashlib.rst b/Doc/library/hashlib.rst
index ad2bfa5..7a65d7d 100644
--- a/Doc/library/hashlib.rst
+++ b/Doc/library/hashlib.rst
@@ -37,6 +37,11 @@
.. note::
+ For better multithreading performance, the Python GIL is released for
+ strings of more than 2047 bytes at object creation or on update.
+
+.. note::
+
Feeding string objects is to :meth:`update` is not supported, as hashes work
on bytes, not on characters.