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GeezerVison is showing github.com — gh-146099: Optimize _GUARD_CODE_VERSION+IP via function version symbols by Fidget-Spinner · Pull Request #146101 · python/cpython

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@Fidget-Spinner

@Fidget-Spinner Fidget-Spinner commented Mar 18, 2026 •
edited by bedevere-app Bot
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  • Issue: Optimize _GUARD_CODE_VERSION and _GUARD_IP__PUSH_FRAME #146099

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@Fidget-Spinner
Optimize _GUARD_CODE_VERSION+IP via fun version symbols
65e1f94
@Fidget-Spinner
Fidget-Spinner requested review from markshannon, savannahostrowski and tomasr8 as code owners March 18, 2026 09:47
@Fidget-Spinner Fidget-Spinner added the skip news label Mar 18, 2026
@bedevere-app bedevere-app Bot mentioned this pull request Mar 18, 2026
Optimize _GUARD_CODE_VERSION and _GUARD_IP__PUSH_FRAME #146099
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@bedevere-app bedevere-app Bot added the awaiting core review label Mar 18, 2026
Fidget-Spinner added 2 commits March 18, 2026 18:10
@Fidget-Spinner
try removing buggy thing
15961e8
@Fidget-Spinner
fix macOS builds
0b05457
markshannon
markshannon requested changes Mar 19, 2026
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Thanks for doing this, the general approach looks sound.
I've spotted one correctness issue, and suggested a few minor tweaks

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Comment thread Python/optimizer_bytecodes.c Outdated
PyCodeObject *co = get_current_code_object(ctx);
if (co->co_version == version) {
_Py_BloomFilter_Add(dependencies, co);
if (sym_get_func_version(ctx->frame->callable) != 0) {

@markshannon markshannon Mar 19, 2026

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Suggested change
if (sym_get_func_version(ctx->frame->callable) != 0) {
if (sym_get_func_version(ctx->frame->callable) == version) {

If the version is different this guard should fail

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Comment thread Python/optimizer_symbols.c Outdated
| KNOWN_CLASS--+ | | |
| | | | | | PREDICATE RECORDED_VALUE(known type)
| | | INT* | | | |
| | | | FUNC_VERSION | | | <- Anything below this level has a known truthiness.

@markshannon markshannon Mar 19, 2026

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The comment says that anything below this line has known truthiness, and functions are always true.
Add a new line below the "Anything below this level has a known truthiness" line

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Comment thread Python/optimizer_symbols.c Outdated
printf("<v%u at %p>", sym->version.version, (void *)sym);
break;
case JIT_SYM_FUNC_VERSION_TAG:
printf("<fv%u at %p>", sym->func_version.func_version, (void *)sym);

@markshannon markshannon Mar 19, 2026

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Suggested change
printf("<fv%u at %p>", sym->func_version.func_version, (void *)sym);
printf("<function version=%u>", sym->func_version.func_version);

Be a bit less cryptic (the pointer contains no useful information)

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Comment thread Python/optimizer_symbols.c Outdated
((PyFunctionObject *)sym->recorded_value.value)->func_version != version) {
sym_set_bottom(ctx, sym);
return false;
}

@markshannon markshannon Mar 19, 2026

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Suggested change
}
}

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@bedevere-app bedevere-app Bot added awaiting changes and removed awaiting core review labels Mar 19, 2026
@bedevere-app

bedevere-app Bot commented Mar 19, 2026

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When you're done making the requested changes, leave the comment: I have made the requested changes; please review again.
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@Fidget-Spinner
Address review
1ae5bbd
@Fidget-Spinner

Fidget-Spinner commented Mar 19, 2026

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I have made the requested changes; please review again.
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@bedevere-app bedevere-app Bot added awaiting change review and removed awaiting changes labels Mar 19, 2026
@bedevere-app

bedevere-app Bot commented Mar 19, 2026

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Thanks for making the requested changes!

@markshannon: please review the changes made to this pull request.
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@bedevere-app
bedevere-app Bot requested a review from markshannon March 19, 2026 14:40
@Fidget-Spinner
reduce diff
418eeea
@Fidget-Spinner

Fidget-Spinner commented Mar 19, 2026 •
edited
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I can confirm this fixes somewhat the regression seen on x86_64 for base16 benchmark in the past few days:

base16_large: Mean +- std dev: [base64_main] 10.2 ms +- 0.2 ms -> [base64_fixed] 9.38 ms +- 0.17 ms: 1.08x faster
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markshannon
markshannon approved these changes Mar 20, 2026
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Looks good now. Thanks

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@bedevere-app bedevere-app Bot added awaiting merge and removed awaiting change review labels Mar 20, 2026
@markshannon
markshannon merged commit acfb452 into python:main Mar 20, 2026
69 of 70 checks passed

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@bedevere-app bedevere-app Bot removed the awaiting merge label Mar 20, 2026
@Fidget-Spinner
Fidget-Spinner deleted the opt_guard_code_version_2 branch March 20, 2026 12:40
@Sacul0457 Sacul0457 mentioned this pull request Mar 21, 2026
gh-131798: Split CHECK_FUNCTION_VERSION into two guards in the JIT #145080
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CuriousLearner added a commit to CuriousLearner/cpython that referenced this pull request Mar 22, 2026
@CuriousLearner
Merge remote-tracking branch 'upstream/main' into fix-pythongh-138577
2691ad9 
* upstream/main: (1475 commits)
  Docs: replace all `datetime` imports with `import datetime as dt` (python#145640)
  pythongh-146153: Use `frozendict` in pure python fallback for `curses.has_key` (python#146154)
  pythongh-138234: clarify returncode behavior for subprocesses created with `shell=True` (python#138536)
  pythongh-140947: fix contextvars handling for server tasks in asyncio  (python#141158)
  pythonGH-100108: Add async generators best practices section (python#141885)
  pythonGH-145667: Merge `GET_ITER` and `GET_YIELD_FROM_ITER` (pythonGH-146120)
  pythongh-146228: Better fork support in cached FastPath (python#146231)
  pythongh-146227: Fix wrong type in _Py_atomic_load_uint16 in pyatomic_std.h (pythongh-146229)
  pythongh-145980: Fix copy/paste mistake in binascii.c (python#146230)
  pythongh-146092: Raise MemoryError on allocation failure in _zoneinfo (python#146165)
  pythongh-91279: Note `SOURCE_DATE_EPOCH` support in `ZipFile.writestr()` doc (python#139396)
  pythongh-146196: Fix Undefined Behavior in _PyUnicodeWriter_WriteASCIIString() (python#146201)
  pythongh-143930: Reject leading dashes in webbrowser URLs
  pythongh-145916: Soft-deprecate ctypes.util.find_library (pythonGH-145919)
  pythongh-146205: Check the errno with != 0 in close impls in select module (python#146206)
  pythongh-146171: Fix nested AttributeError suggestions (python#146188)
  pythongh-146099: Optimize _GUARD_CODE_VERSION+IP via function version symbols (pythonGH-146101)
  pythongh-145980: Add support for alternative alphabets in the binascii module (pythonGH-145981)
  pythongh-145754: Update signature retrieval in unittest.mock to use forwardref annotation format (python#145756)
  pythongh-145177: Add emscripten run --test, uses test args from config.toml (python#146160)
  ...
@pablogsal pablogsal mentioned this pull request Apr 4, 2026
gh-130273: Fix traceback color output with unicode characters #142529
Merged
ljfp pushed a commit to ljfp/cpython that referenced this pull request Apr 25, 2026
@Fidget-Spinner @ljfp
pythongh-146099: Optimize _GUARD_CODE_VERSION+IP via function version…
13792cd 
… symbols (pythonGH-146101)
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Reviewers

@markshannon markshannon markshannon approved these changes
@tomasr8 tomasr8 Awaiting requested review from tomasr8 tomasr8 is a code owner
@savannahostrowski savannahostrowski Awaiting requested review from savannahostrowski

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2 participants

@Fidget-Spinner @markshannon
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