gh-149202: Implement PEP 831 – Frame Pointers Everywhere: Enabling System-Level Observability for Python by pablogsal · Pull Request #149201 · python/cpython · GitHub

Issue: Implement PEP 831 – Frame Pointers Everywhere: Enabling System-Level Observability for Python #149202

Closes: #96174 #149202

CC: @savannahostrowski @Fidget-Spinner @diegorusso

Documentation build overview

📚 cpython-previews | 🛠️ Build #32502418 | 📁 Comparing af6c75e against main (bdbb55c)

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21 files changed · ± 21 modified

± Modified

I think this also closes out on #96174 👀

…into frame-pointers

@savannahostrowski We need a what's new entry as well i can add one tomorrow if you don't beat me to it. Also we need to tell people to add the option in their custom build systems as well

I read the configure.ac code in detail, and looked at the docs as well.

lgtm!

One minor configure wording question, but otherwise looks good!

Co-authored-by: Hugo van Kemenade <1324225+hugovk@users.noreply.github.com>

Co-authored-by: Emma Smith <emma@emmatyping.dev>

Thanks for the reviews, folks!

@pablogsal I've added a What's New and guidance for downstream folks too!

Updating main to include #149248 to fix CI.

test_manual_unwind_respects_frame_pointers is failing on the S390x buildbots:

https://buildbot.python.org/#/release_status

test_manual_unwind_respects_frame_pointers (test.test_frame_pointer_unwind.FramePointerUnwindTests.test_manual_unwind_respects_frame_pointers) ... 
  test_manual_unwind_respects_frame_pointers (test.test_frame_pointer_unwind.FramePointerUnwindTests.test_manual_unwind_respects_frame_pointers) (env={'PYTHON_JIT': '0'}) ... FAIL

Stdout:
#00 0x3ff7fa759d0 -> other
{"length": 1, "python_frames": 0, "jit_frames": 0, "other_frames": 1, "jit_backend": null}

======================================================================
FAIL: test_manual_unwind_respects_frame_pointers (test.test_frame_pointer_unwind.FramePointerUnwindTests.test_manual_unwind_respects_frame_pointers) (env={'PYTHON_JIT': '0'})
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/var/lib/buildbot/worker/cstratak-fedora-stable-s390x/3.x.cstratak-fedora-stable-s390x/build/Lib/test/test_frame_pointer_unwind.py", line 205, in test_manual_unwind_respects_frame_pointers
    self.assertGreater(
    ~~~~~~~~~~~~~~~~~~^
        python_frames,
        ^^^^^^^^^^^^^^
        0,
        ^^
        f"expected to find Python frames on {self.machine} with env {env}",
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    )
    ^
AssertionError: 0 not greater than 0 : expected to find Python frames on s390x with env {'PYTHON_JIT': '0'}

Stdout:
#00 0x3ff7fa759d0 -> other
{"length": 1, "python_frames": 0, "jit_frames": 0, "other_frames": 1, "jit_backend": null}

It's also failing on ARM Raspbian (on aarch64 with env {'PYTHON_JIT': '0'}).

I've seen the failures. Today I cannot see what's going on. It's bank holiday in the UK. I think I can replicate a Raspbian OS. In case I need is there a way to login on the S390x?
What I notice though is that the classifications of the frames is broken on these platforms.

Stdout:
#00 0x3ff7fa759d0 -> other
{"length": 1, "python_frames": 0, "jit_frames": 0, "other_frames": 1, "jit_backend": null}

Are these the platforms without -mno-omit-leaf-frame-pointer?

checking whether C compiler accepts -mno-omit-leaf-frame-pointer... no

In case I need is there a way to login on the S390x?

That would be a question for @vstinner

I was able to reproduce in a container with QEMU (podman run --rm -it --arch s390x -v $PWD:/workspace:O fedora bash; install deps), but, it's late so I'll stop here today.

Pls check #149362 for an explanation of the problem and a fix

But long story short: a mix of the test is wrong and we are missing flags.

pablogsal requested review from AA-Turner, corona10, emmatyping and erlend-aasland as code owners April 30, 2026 22:31

bedevere-app Bot added the awaiting core review label Apr 30, 2026

pablogsal changed the title Implement PEP 831 – Frame Pointers Everywhere: Enabling System-Level Observability for Python gh-149202: Implement PEP 831 – Frame Pointers Everywhere: Enabling System-Level Observability for Python Apr 30, 2026

bedevere-app Bot mentioned this pull request Apr 30, 2026

Implement PEP 831 – Frame Pointers Everywhere: Enabling System-Level Observability for Python #149202

Closed

Enable frame pointers by default for CPython builds

c1347c5

pablogsal force-pushed the frame-pointers branch from 9d611e5 to c1347c5 Compare April 30, 2026 22:41

savannahostrowski added 2 commits April 30, 2026 16:25

Add --without-frame-pointers flag and docs

fc6d6be

Doc tweaks

166bf7e

savannahostrowski added 3 commits April 30, 2026 16:30

Merge branch 'main' into frame-pointers

4be8ac4

being kinda particular in my wording here, sorry

0cebe81

Merge branch 'frame-pointers' of https://github.com/pablogsal/cpython …

2efc0a2

…into frame-pointers

Fidget-Spinner approved these changes May 1, 2026

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bedevere-app Bot added awaiting merge and removed awaiting core review labels May 1, 2026

corona10 approved these changes May 1, 2026

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emmatyping reviewed May 1, 2026

View reviewed changes

Comment thread configure.ac Outdated

emmatyping approved these changes May 1, 2026

View reviewed changes

hugovk reviewed May 1, 2026

View reviewed changes

Comment thread Doc/whatsnew/3.15.rst

savannahostrowski and others added 4 commits May 1, 2026 11:05

Apply suggestion from @hugovk

bc1cdfb

Co-authored-by: Hugo van Kemenade <1324225+hugovk@users.noreply.github.com>

Update configure.ac

d40aca5

Co-authored-by: Emma Smith <emma@emmatyping.dev>

Add to release highlights

dd0f02c

Add guidance

7695f4c

Merge branch 'main' into frame-pointers

e606239

Merge branch 'main' into frame-pointers

af6c75e

pablogsal merged commit 3236773 into python:main May 1, 2026
55 checks passed

pablogsal deleted the frame-pointers branch May 1, 2026 20:16

bedevere-app Bot removed the awaiting merge label May 1, 2026

florianl mentioned this pull request May 4, 2026

python: use frame pointer unwinding open-telemetry/opentelemetry-ebpf-profiler#1389

Open

hanshal101 mentioned this pull request May 9, 2026

fix: make use of frame pointer unwinding on python3.15 open-telemetry/opentelemetry-ebpf-profiler#1404

Closed

gh-149202: Implement PEP 831 – Frame Pointers Everywhere: Enabling System-Level Observability for Python by pablogsal · Pull Request #149201 · python/cpython · GitHub

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gh-149202: Implement PEP 831 – Frame Pointers Everywhere: Enabling System-Level Observability for Python - #149201

gh-149202: Implement PEP 831 – Frame Pointers Everywhere: Enabling System-Level Observability for Python#149201pablogsal merged 12 commits intopython:mainpython/cpython:mainfrom pablogsal:frame-pointerspablogsal/cpython:frame-pointersCopy head branch name to clipboard

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gh-149202: Implement PEP 831 – Frame Pointers Everywhere: Enabling System-Level Observability for Python#149201
pablogsal merged 12 commits into
python:mainfrom
pablogsal:frame-pointers

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