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gh-115999: Implement thread-local bytecode and enable specialization for BINARY_OP (#123926)

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Each thread specializes a thread-local copy of the bytecode, created on the first RESUME, in free-threaded builds. All copies of the bytecode for a code object are stored in the co_tlbc array on the code object. Threads reserve a globally unique index identifying its copy of the bytecode in all co_tlbc arrays at thread creation and release the index at thread destruction. The first entry in every co_tlbc array always points to the "main" copy of the bytecode that is stored at the end of the code object. This ensures that no bytecode is copied for programs that do not use threads.

Thread-local bytecode can be disabled at runtime by providing either -X tlbc=0 or PYTHON_TLBC=0. Disabling thread-local bytecode also disables specialization.

Concurrent modifications to the bytecode made by the specializing interpreter and instrumentation use atomics, with specialization taking care not to overwrite an instruction that was instrumented concurrently.
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mpage 2024-11-04 11:13:32 -08:00 • committed by GitHub
parent e5a4b402ae
commit 2e95c5ba3b
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44 changed files with 1510 additions and 255 deletions
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52
Lib/test/test_cmd_line.py
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@ -12,6 +12,7 @@ import unittest
from test import support
from test.support import os_helper
from test.support import force_not_colorized
from test.support import threading_helper
from test.support.script_helper import (
spawn_python, kill_python, assert_python_ok, assert_python_failure,
interpreter_requires_environment
@ -1068,6 +1069,57 @@ class CmdLineTest(unittest.TestCase):
out = res.out.strip().decode("utf-8")
return tuple(int(i) for i in out.split())
@unittest.skipUnless(support.Py_GIL_DISABLED,
"PYTHON_TLBC and -X tlbc"
" only supported in Py_GIL_DISABLED builds")
@threading_helper.requires_working_threading()
def test_disable_thread_local_bytecode(self):
code = """if 1:
import threading
def test(x, y):
return x + y
t = threading.Thread(target=test, args=(1,2))
t.start()
t.join()"""
assert_python_ok("-W", "always", "-X", "tlbc=0", "-c", code)
assert_python_ok("-W", "always", "-c", code, PYTHON_TLBC="0")
@unittest.skipUnless(support.Py_GIL_DISABLED,
"PYTHON_TLBC and -X tlbc"
" only supported in Py_GIL_DISABLED builds")
@threading_helper.requires_working_threading()
def test_enable_thread_local_bytecode(self):
code = """if 1:
import threading
def test(x, y):
return x + y
t = threading.Thread(target=test, args=(1,2))
t.start()
t.join()"""
# The functionality of thread-local bytecode is tested more extensively
# in test_thread_local_bytecode
assert_python_ok("-W", "always", "-X", "tlbc=1", "-c", code)
assert_python_ok("-W", "always", "-c", code, PYTHON_TLBC="1")
@unittest.skipUnless(support.Py_GIL_DISABLED,
"PYTHON_TLBC and -X tlbc"
" only supported in Py_GIL_DISABLED builds")
def test_invalid_thread_local_bytecode(self):
rc, out, err = assert_python_failure("-X", "tlbc")
self.assertIn(b"tlbc=n: n is missing or invalid", err)
rc, out, err = assert_python_failure("-X", "tlbc=foo")
self.assertIn(b"tlbc=n: n is missing or invalid", err)
rc, out, err = assert_python_failure("-X", "tlbc=-1")
self.assertIn(b"tlbc=n: n is missing or invalid", err)
rc, out, err = assert_python_failure("-X", "tlbc=2")
self.assertIn(b"tlbc=n: n is missing or invalid", err)
rc, out, err = assert_python_failure(PYTHON_TLBC="foo")
self.assertIn(b"PYTHON_TLBC=N: N is missing or invalid", err)
rc, out, err = assert_python_failure(PYTHON_TLBC="-1")
self.assertIn(b"PYTHON_TLBC=N: N is missing or invalid", err)
rc, out, err = assert_python_failure(PYTHON_TLBC="2")
self.assertIn(b"PYTHON_TLBC=N: N is missing or invalid", err)
@unittest.skipIf(interpreter_requires_environment(),
'Cannot run -I tests when PYTHON env vars are required.')