python / python/cpython

perf trampoline tests fail after BOLT optimizations

Open
#128,883 0 comments 0 reactions 0 assignees View on GitHub

Nobody has claimed this yet.

tests type-bug
Dominant language
Python
Stars
77.2k
Forks
35.9k
PR merge metrics
PR metrics pending

Description

Bug report

Bug description:

As initially reported in https://github.com/python/cpython/pull/128845. The following tests fail

test_sys_api (test.test_perf_profiler.TestPerfTrampoline.test_sys_api) ... FAIL
test_trampoline_works (test.test_perf_profiler.TestPerfTrampoline.test_trampoline_works) ... FAIL
test_trampoline_works_with_forks (test.test_perf_profiler.TestPerfTrampoline.test_trampoline_works_with_forks) ... FAIL

======================================================================
FAIL: test_sys_api (test.test_perf_profiler.TestPerfTrampoline.test_sys_api)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/runner/work/cpython/cpython-ro-srcdir/Lib/test/test_perf_profiler.py", line 203, in test_sys_api
    self.assertIn(f"py::spam:{script}", perf_file_contents)
    ~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: 'py::spam:/tmp/test_python_qxe1_ajb/tmpqablk9qp/perftest.py' not found in '7f2d97946000 80600b py::baz:/tmp/test_python_qxe1_ajb/tmpqablk9qp/perftest.py\n'

======================================================================
FAIL: test_trampoline_works (test.test_perf_profiler.TestPerfTrampoline.test_trampoline_works)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/runner/work/cpython/cpython-ro-srcdir/Lib/test/test_perf_profiler.py", line 91, in test_trampoline_works
    self.assertIsNotNone(
    ~~~~~~~~~~~~~~~~~~~~^
        perf_line, f"Could not find {expected_symbol} in perf file"
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    )
    ^
AssertionError: unexpectedly None : Could not find py::foo:/tmp/test_python_qxe1_ajb/tmpdd3d4w9f/perftest.py in perf file

======================================================================
FAIL: test_trampoline_works_with_forks (test.test_perf_profiler.TestPerfTrampoline.test_trampoline_works_with_forks)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/runner/work/cpython/cpython-ro-srcdir/Lib/test/test_perf_profiler.py", line 145, in test_trampoline_works_with_forks
    self.assertEqual(process.returncode, 0)
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: -11 != 0

----------------------------------------------------------------------
Ran 3 tests in 0.463s

FAILED (failures=3)
test test_perf_profiler failed
1 test failed again:
    test_perf_profiler
CPython versions tested on:

CPython main branch

Operating systems tested on:

Linux

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start with Lib/test/test_perf_profiler.py and reproduce the three failing TestPerfTrampoline tests on Linux after BOLT optimizations. Trace why the expected perf symbols are missing and why the forked process exits with -11. Done means test_sys_api, test_trampoline_works, and test_trampoline_works_with_forks pass.

Written by the indexing model from the issue text.

Assessment

Tech stack
python
Domain
performance, testing-qa
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

Get new issues in your inbox

A short digest of beginner-friendly GitHub issues.