Skip to content

gh-153198 Optimize set and frozenset membership lookup #153199

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
rajat315315 wants to merge 3 commits into
base: main
Choose a base branch
from
+7 −1
Open

gh-153198 Optimize set and frozenset membership lookup #153199

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
d25015b
perf: optimize set lookups by inlining set_do_lookup and adding a fas…
rajat315315 Jul 6, 2026
81f2fa7
perf: optimize set and frozenset membership lookup by inlining lookup…
rajat315315 Jul 6, 2026
110770e
Merge branch 'main' into set_membership_opt
rajat315315 Jul 6, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
1 change: 1 addition & 0 deletions Misc/NEWS.d/next/Core_and_Builtins/2026-07-06-14-25-00.gh-issue-153199.abc123.rst
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1 @@
Optimize set and frozenset membership lookup by inlining ``set_do_lookup`` and adding a ``PyUnicode_CheckExact`` fast path to ``set_compare_frozenset``.
7 changes: 6 additions & 1 deletion Objects/setobject.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -182,6 +182,11 @@ set_compare_frozenset(PySetObject *so, setentry *table, setentry *ep,
}
Py_ssize_t ep_hash = ep->hash;
if (ep_hash == hash) {
if (PyUnicode_CheckExact(startkey)
&& PyUnicode_CheckExact(key)
&& unicode_eq(startkey, key)) {
return SET_LOOKKEY_FOUND;
}
int cmp = PyObject_RichCompareBool(startkey, key, Py_EQ);
if (cmp < 0) {
return SET_LOOKKEY_ERROR;
Expand Down Expand Up @@ -217,7 +222,7 @@ set_zero_table(setentry *table, size_t size)
/* This must be >= 1 */
#define PERTURB_SHIFT 5

static int
static inline Py_ALWAYS_INLINE int

@StanFromIreland StanFromIreland Jul 6, 2026

Copy link
Copy Markdown
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Is the compiler not already specialising this?

set_do_lookup(PySetObject *so, setentry *table, size_t mask, PyObject *key,
Py_hash_t hash, setentry **epp, compare_func compare_entry)
{
Expand Down
Loading