From: Sam Gross <colesbury@gmail.com>
Date: Fri, 10 Jan 2025 00:59:10 +0000 (-0500)
Subject: gh-128691: Use deferred reference counting on `_thread._local` (#128693)
X-Git-Tag: v3.14.0a4~52
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=c1417487e98e270d614965ed78ff9439044b65a6;p=thirdparty%2FPython%2Fcpython.git

gh-128691: Use deferred reference counting on `_thread._local` (#128693)

This change, along with the LOAD_ATTR specializations, makes the
"thread_local_read" micro benchmark in Tools/ftscalingbench/ftscalingbench.py
scale well to multiple threads.
---

diff --git a/Modules/_threadmodule.c b/Modules/_threadmodule.c
index 2cbdfeb09b95..d19ae326bd6b 100644
--- a/Modules/_threadmodule.c
+++ b/Modules/_threadmodule.c
@@ -1414,6 +1414,10 @@ local_new(PyTypeObject *type, PyObject *args, PyObject *kw)
         return NULL;
     }
 
+    // gh-128691: Use deferred reference counting for thread-locals to avoid
+    // contention on the shared object.
+    _PyObject_SetDeferredRefcount((PyObject *)self);
+
     self->args = Py_XNewRef(args);
     self->kw = Py_XNewRef(kw);