`test_profiling` sometimes times out under TSan

We don't currently run test_profiling in the TSan CI, but the context is that I'm trying to get the entire test suite running under thread sanitizer (TSan).

Some of the tests in test_profiling fail to attach in time when run with thread sanitizer, because the sanitizer makes everything slower. This is especially the case when running tests in parallel with -j.

Here's a example:

ERROR: test_run_failed_script_live (test.test_profiling.test_sampling_profiler.test_live_collector_ui.TestLiveModeErrors.test_run_failed_script_live)
Test that running a failing script exits with clean error.
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/sgross/tsan-cpython/Lib/profiling/sampling/cli.py", line 279, in _run_with_sync
    _wait_for_ready_signal(sync_sock, process, _SYNC_TIMEOUT_SEC)
    ~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/sgross/tsan-cpython/Lib/profiling/sampling/cli.py", line 223, in _wait_for_ready_signal
    raise socket.timeout("timed out")
TimeoutError: timed out

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/home/sgross/tsan-cpython/Lib/profiling/sampling/cli.py", line 1110, in _handle_live_run
    process = _run_with_sync(cmd, suppress_output=True)
  File "/home/sgross/tsan-cpython/Lib/profiling/sampling/cli.py", line 289, in _run_with_sync
    raise RuntimeError(
        "Process failed to signal readiness within timeout"
    )
RuntimeError: Process failed to signal readiness within timeout

I think the problem is that the the _SYNC_TIMEOUT_SEC of 5 seconds isn't enough in this case:

https://github.com/python/cpython/blob/4f9a8d075ee52b8f56aca14102c8bf9fd6f3c512/Lib/profiling/sampling/cli.py#L78

Here are some options to consider:

1. Make _SYNC_TIMEOUT_SEC configurable via a command line option and specify a larger value for the tests (i.e., SHORT_TIMEOUT)
2. Make _SYNC_TIMEOUT_SEC configurable via environment variable
3. Skip these tests under TSan
4. ???

cc @pablogsal

Commencez dans Lib/profiling/sampling/cli.py, au niveau de _SYNC_TIMEOUT_SEC et _wait_for_ready_signal, puis examinez le cas test_profiling en échec test_run_failed_script_live. Exécutez les tests de profiling sous TSan, y compris l’exécution en parallèle avec -j, et comparez les conventions existantes des tests pour le comportement spécifique aux sanitizers. Le travail est terminé lorsque les tests concernés se terminent de manière fiable sous TSan sans affaiblir la couverture normale des tests.