gh-142889: Restructure PyDictKeysObject memory layout for simpler access#145097
gh-142889: Restructure PyDictKeysObject memory layout for simpler access#145097clintonsteiner wants to merge 4 commits intopython:mainfrom
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…er entry access Restructure dict keys allocation to store dk_indices before the PyDictKeysObject header and keep dk_entries after the header. Update dict index access and related allocation/free/clone paths, adjust gdb dict entry location logic, and add layout coverage tests. Local dict microbenchmarks showed about a 1.4% overall improvement, with most operations around 1-2% faster.
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| @@ -16,7 +16,6 @@ As of Python 3.6, this is compact and ordered. Basic idea is described here: | |||
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Does this layout comment need updating (move dk_entries[] to the top and demark where a PyDictKeysObject * actually points to)?
Also, I feel like the definition for PyDictKeysObject (struct _dictkeysobject) needs updating:
cpython/Include/internal/pycore_dict.h
Lines 175 to 219 in 5944a53
Probably just change char dk_indices[] to char dk_entries[] and add a comment saying that dk_indicies will be put above the header. I'm not sure about the consequences of renaming dk_indices though, so you could also just add a comment.
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Updated, was trying to keep diff small but agreed this is no longer applicable
Restructure dict keys allocation to store dk_indices before the PyDictKeysObject header and keep dk_entries after the header.
Update dict index access and related allocation/free/clone paths, adjust gdb dict entry location logic, and add layout coverage tests.
Local dict microbenchmarks showed about a 1.4% overall improvement, with most operations around 1-2% faster.