Description

assignee = None
closed_at = None
created_at = <Date 2022-03-01.22:13:38.844>
labels = ['interpreter-core', '3.11', 'type-feature', 'expert-asyncio']
title = 'Async Call-Stack Reconstruction'
updated_at = <Date 2022-03-12.09:30:23.838>
user = 'https://github.com/mpage'

activity = <Date 2022-03-12.09:30:23.838>
actor = 'asvetlov'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['Interpreter Core', 'asyncio']
creation = <Date 2022-03-01.22:13:38.844>
creator = 'mpage'
dependencies = []
files = []
hgrepos = []
issue_num = 46892
keywords = []
message_count = 5.0
messages = ['414301', '414884', '414930', '414948', '414985']
nosy_count = 7.0
nosy_names = ['gvanrossum', 'dino.viehland', 'asvetlov', 'yselivanov', 'kumaraditya', 'itamaro', 'mpage']
pr_nums = []
priority = 'normal'
resolution = None
stage = None
status = 'open'
superseder = None
type = 'enhancement'
url = 'https://bugs.python.org/issue46892'
versions = ['Python 3.11']

Activity

1. mpage commented on Mar 1, 2022

   

   mpagemannequin

   on Mar 1, 2022

   MannequinAuthor

   More actions

   Profiling tools that use the call-stack (i.e. all of them) paint an incomplete picture of what’s really going on in async-heavy codebases. They can only show the stack of the currently executing task; they miss the chain of awaitables that are transitively waiting on the current task. To remedy this, we have added support in Cinder to expose the async call-stack. This consists of the call stack for the currently executing task, followed by the chain of awaitables that are transitively reachable from the currently executing task. See below for a clarifying example.

   async def f1():
     return await f2()
   
   async def f2():
     return await asyncio.ensure_future(f3())
   
   async def f3():
     return await f4()
   
   async def f4():
     await asyncio.sleep(10)
     return 42
   

   When retrieved from f4, the two different stacks (top-of-stack last) are:
   sync - [f3, f4]
   async - [f1, f2, f3, f4]

   We’d like to merge our implementation into CPython so that other heavy users of asyncio can benefit. This will consist of a few parts:

   1. A new limited C-API to set and retrieve the “awaiter” of an awaitable object.
   2. Additions to PyAsyncMethods to store function pointers for setting and retrieving the awaiter on instances.
   3. An API in managed code to retrieve the async call stack as a list of fully qualified names (i.e. <module>:<class>.<function>).

   Reacted by Bruno Cabral, Itamar Oren, Zsolt Dollenstein, Jon Janzen, gfolkmanis-nhgh, Zeke Marffy, Savio Mak, Isaac Nygaard and Daniel Limón
2. mpage

   added

   3.11only security fixesonly security fixes

   interpreter-core(Objects, Python, Grammar, and Parser dirs)(Objects, Python, Grammar, and Parser dirs)

   topic-asyncio

   type-featureA feature request or enhancementA feature request or enhancement

   on Mar 1, 2022
3. asvetlov commented on Mar 11, 2022

   

   asvetlov

   on Mar 11, 2022

   Contributor

   More actions

   We’d like to merge our implementation into CPython

   Could you provide a link first, please?
4. mpage commented on Mar 11, 2022

   

   mpagemannequin

   on Mar 11, 2022

   MannequinAuthor

   More actions

   Sorry for the confusion, I'm working on a PR. I filed the BPO to gauge interest in the feature.
5. gvanrossum commented on Mar 11, 2022

   

   gvanrossum

   on Mar 11, 2022

   Member

   More actions

   I've recently dabbled a bit in some new primitives for asyncio, and based on that experience I think this would be very useful.

   IIRC Trio does this (presumably at considerable cost) in userland.
6. asvetlov commented on Mar 12, 2022

   

   asvetlov

   on Mar 12, 2022

   Contributor

   More actions

   The idea looks interesting.
   The devil in the details I guess.
   I'm curious what is the memory and performance penalty.
   Waiting for the PR as the discussion starting point.
7. ezio-melotti

   transferred this issue fromon Apr 10, 2022
8. ezio-melotti

   added this to asyncioon Jul 17, 2022
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10. github-project-automation

    moved this from Todo to Done in asyncioon Aug 18, 2025
11. Agent-Hellboy

    added 2 commits that reference this issue on Aug 19, 2025

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12. kumaraditya303

    added a commit that references this issue on Sep 9, 2025

    [3.14] pythongh-91048: Revert the memory cache removal for remote deb…

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13. pablogsal

    added 5 commits that reference this issue on Dec 17, 2025

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    pythongh-91048: Refactor common data into context object in Modukes/_…

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    gh-91048: Refactor common data into context object in Modules/_remote…

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14. gostak-dd

    added 4 commits that reference this issue on Jun 2, 2026

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15. chrisguidry

    added 2 commits that reference this issue on Jul 20, 2026

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    f2a8af8

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    733772c

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