Merged revisions 70647,70652 via svnmerge from

svn+ssh://pythondev@svn.python.org/python/trunk

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  r70647 | antoine.pitrou | 2009-03-28 20:10:13 +0100 (sam., 28 mars 2009) | 3 lines

  Publicize the GC untracking optimization
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  r70652 | antoine.pitrou | 2009-03-28 20:17:54 +0100 (sam., 28 mars 2009) | 3 lines

  Fix a typo and be more specific
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Doc/whatsnew/2.7.rst

@@ -129,6 +129,18 @@ A few performance enhancements have been added:
   (Suggested by Martin von Loewis and implemented by Antoine Pitrou;
   :issue:`4074`.)
 
+* The garbage collector tries to avoid tracking simple containers which
+  can't be part of a cycle. As of now, this is true for tuples and dicts
+  containing atomic types (such as ints, strings, etc.). Transitively, a dict
+  containing tuples of atomic types won't be tracked either. This helps bring
+  down the individual cost of each garbage collection, since it decreases the
+  number of objects to be considered and traversed by the collector.
+
+  To help diagnosing this optimization, a new function in the :mod:`gc`
+  module, :func:`is_tracked`, returns True if a given instance is tracked
+  by the garbage collector, False otherwise.
+  (Contributed by Antoine Pitrou; :issue:`4688`.)
+
 
 .. ======================================================================