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gh-115999: Add free-threaded specialization for UNPACK_SEQUENCE #126600

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Merged
merged 7 commits into from
Nov 22, 2024
Merged

gh-115999: Add free-threaded specialization for UNPACK_SEQUENCE #126600

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5e0d875
Add FT specialization
Eclips4 Nov 8, 2024
fa8ff2f
Add test case
Eclips4 Nov 8, 2024
d49e9e6
Address Matt's review
Eclips4 Nov 8, 2024
ea1abf3
Refactor UNPACK_SEQUENCE_LIST
mpage Nov 15, 2024
7ad46ad
Merge branch 'main' into ft-specialize-unpack-sequence
Eclips4 Nov 21, 2024
66a2d67
Align PR with recent changes
Eclips4 Nov 21, 2024
16093d6
Update Python/specialize.c
Eclips4 Nov 21, 2024
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2 changes: 1 addition & 1 deletion Include/internal/pycore_opcode_metadata.h
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2 changes: 1 addition & 1 deletion Include/internal/pycore_uop_metadata.h
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31 changes: 31 additions & 0 deletions Lib/test/test_opcache.py
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Original file line number Diff line number Diff line change
Expand Up @@ -1256,6 +1256,37 @@ def g():
self.assert_no_opcode(g, "CONTAINS_OP")


@cpython_only
@requires_specialization_ft
def test_unpack_sequence(self):
def f():
for _ in range(100):
a, b = 1, 2
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Sort of unrelated to this PR, but I'm surprised constant unpacking like this isn't peepholed into LOAD_CONST, STORE_FAST, LOAD_CONST, STORE_FAST. Maybe because it's actually a longer instruction sequence than the original? It certainly does less work.

@iritkatriel, thoughts?

self.assertEqual(a, 1)
self.assertEqual(b, 2)

f()
self.assert_specialized(f, "UNPACK_SEQUENCE_TWO_TUPLE")
self.assert_no_opcode(f, "UNPACK_SEQUENCE")

def g():
for _ in range(100):
a, = 1,
self.assertEqual(a, 1)

g()
self.assert_specialized(g, "UNPACK_SEQUENCE_TUPLE")
self.assert_no_opcode(g, "UNPACK_SEQUENCE")

def x():
for _ in range(100):
a, b = [1, 2]
self.assertEqual(a, 1)
self.assertEqual(b, 2)

x()
self.assert_specialized(x, "UNPACK_SEQUENCE_LIST")
self.assert_no_opcode(x, "UNPACK_SEQUENCE")

if __name__ == "__main__":
unittest.main()
20 changes: 16 additions & 4 deletions Python/bytecodes.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1381,15 +1381,15 @@ dummy_func(
};

specializing op(_SPECIALIZE_UNPACK_SEQUENCE, (counter/1, seq -- seq)) {
#if ENABLE_SPECIALIZATION
#if ENABLE_SPECIALIZATION_FT
if (ADAPTIVE_COUNTER_TRIGGERS(counter)) {
next_instr = this_instr;
_Py_Specialize_UnpackSequence(seq, next_instr, oparg);
DISPATCH_SAME_OPARG();
}
OPCODE_DEFERRED_INC(UNPACK_SEQUENCE);
ADVANCE_ADAPTIVE_COUNTER(this_instr[1].counter);
#endif /* ENABLE_SPECIALIZATION */
#endif /* ENABLE_SPECIALIZATION_FT */
(void)seq;
(void)counter;
}
Expand Down Expand Up @@ -1429,12 +1429,24 @@ dummy_func(
inst(UNPACK_SEQUENCE_LIST, (unused/1, seq -- values[oparg])) {
PyObject *seq_o = PyStackRef_AsPyObjectBorrow(seq);
DEOPT_IF(!PyList_CheckExact(seq_o));
DEOPT_IF(PyList_GET_SIZE(seq_o) != oparg);
#ifdef Py_GIL_DISABLED
PyCriticalSection cs;
PyCriticalSection_Begin(&cs, seq_o);
#endif
if (PyList_GET_SIZE(seq_o) != oparg) {
#ifdef Py_GIL_DISABLED
PyCriticalSection_End(&cs);
#endif
DEOPT_IF(true);
}
STAT_INC(UNPACK_SEQUENCE, hit);
PyObject **items = _PyList_ITEMS(seq_o);
for (int i = oparg; --i >= 0; ) {
*values++ = PyStackRef_FromPyObjectNew(items[i]);
}
#ifdef Py_GIL_DISABLED
PyCriticalSection_End(&cs);
#endif
DECREF_INPUTS();
}

Expand Down Expand Up @@ -2512,7 +2524,7 @@ dummy_func(
}
OPCODE_DEFERRED_INC(CONTAINS_OP);
ADVANCE_ADAPTIVE_COUNTER(this_instr[1].counter);
#endif /* ENABLE_SPECIALIZATION */
#endif /* ENABLE_SPECIALIZATION_FT */
}

macro(CONTAINS_OP) = _SPECIALIZE_CONTAINS_OP + _CONTAINS_OP;
Expand Down
22 changes: 20 additions & 2 deletions Python/executor_cases.c.h
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26 changes: 22 additions & 4 deletions Python/generated_cases.c.h
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30 changes: 12 additions & 18 deletions Python/specialize.c
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Original file line number Diff line number Diff line change
Expand Up @@ -2485,39 +2485,33 @@ _Py_Specialize_UnpackSequence(_PyStackRef seq_st, _Py_CODEUNIT *instr, int oparg
{
PyObject *seq = PyStackRef_AsPyObjectBorrow(seq_st);

assert(ENABLE_SPECIALIZATION);
assert(ENABLE_SPECIALIZATION_FT);
assert(_PyOpcode_Caches[UNPACK_SEQUENCE] ==
INLINE_CACHE_ENTRIES_UNPACK_SEQUENCE);
_PyUnpackSequenceCache *cache = (_PyUnpackSequenceCache *)(instr + 1);
if (PyTuple_CheckExact(seq)) {
if (PyTuple_GET_SIZE(seq) != oparg) {
SPECIALIZATION_FAIL(UNPACK_SEQUENCE, SPEC_FAIL_EXPECTED_ERROR);
goto failure;
unspecialize(instr);
return;
}
if (PyTuple_GET_SIZE(seq) == 2) {
instr->op.code = UNPACK_SEQUENCE_TWO_TUPLE;
goto success;
specialize(instr, UNPACK_SEQUENCE_TWO_TUPLE);
return;
}
instr->op.code = UNPACK_SEQUENCE_TUPLE;
goto success;
specialize(instr, UNPACK_SEQUENCE_TUPLE);
return;
}
if (PyList_CheckExact(seq)) {
if (PyList_GET_SIZE(seq) != oparg) {
SPECIALIZATION_FAIL(UNPACK_SEQUENCE, SPEC_FAIL_EXPECTED_ERROR);
goto failure;
unspecialize(instr);
return;
}
instr->op.code = UNPACK_SEQUENCE_LIST;
goto success;
specialize(instr, UNPACK_SEQUENCE_LIST);
return;
}
SPECIALIZATION_FAIL(UNPACK_SEQUENCE, unpack_sequence_fail_kind(seq));
failure:
STAT_INC(UNPACK_SEQUENCE, failure);
instr->op.code = UNPACK_SEQUENCE;
cache->counter = adaptive_counter_backoff(cache->counter);
return;
success:
STAT_INC(UNPACK_SEQUENCE, success);
cache->counter = adaptive_counter_cooldown();
unspecialize(instr);
}

#ifdef Py_STATS
Expand Down
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