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gh-97696: asyncio eager tasks factory by itamaro · Pull Request #102853 · python/cpython · GitHub
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gh-97696: asyncio eager tasks factory#102853

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carljm merged 38 commits into
python:mainfrom
itamaro:eager-tasks-factory
May 1, 2023
Merged

gh-97696: asyncio eager tasks factory#102853
carljm merged 38 commits into
python:mainfrom
itamaro:eager-tasks-factory

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itamaro commented Mar 20, 2023 •
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fixes gh-97696

pyperformance results:

  • async tree benchmarks up to ~50% faster when using the eager tasks factory (depending on how many leaf nodes actually suspend)
  • geometric mean for all benchmark 1% faster

pyperformance run performed with local patch that installs the eager tasks factory by default (modifying the benchmark itself to use it requires psf/pyperf#157)

full comparison in this gist

bedevere-bot mentioned this pull request Mar 20, 2023
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itamaro force-pushed the eager-tasks-factory branch from 2a961d3 to 245a52b Compare March 20, 2023 22:21
carljm reviewed Mar 20, 2023
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Comment thread Doc/library/asyncio-task.rst Outdated Show resolved Hide resolved
itamaro force-pushed the eager-tasks-factory branch from 245a52b to bcf40dc Compare March 20, 2023 23:04

itamaro commented Mar 21, 2023

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I'm still chasing a refleak, but otherwise this should be ready for review

itamaro marked this pull request as ready for review March 21, 2023 03:37
gvanrossum reviewed Mar 21, 2023
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gvanrossum commented Mar 22, 2023 •
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It looks like @graingert's observation is a serious problem. How can we fix this?

itamaro and others added 8 commits April 20, 2023 13:42
Eager task factory implementation
a127f98
Eager task factory tests
45316d8
Add NEWS and docs for eager task factory
ac9b7b0
elaborate explanation in docs and add a whatsnew entry
402c317
fix docs
563ffd4
Overhaul eager task factory design …
6f2a47a
Always create a task object to resolve the design flaw with structured concurrency. Push the eager step execution into the task implementation, so the task itself knows to eagerly execute the first step if created via the eager task factory. Co-authored-by: Jacob Bower <jbower@meta.com>
Fix task-counting tests for new impl
e7743f6
Fix test_task_exc_handler_correct_context …
10a03a0
Co-authored-by: Jacob Bower <jbower@meta.com>
itamaro force-pushed the eager-tasks-factory branch from 29d04c2 to 10a03a0 Compare April 21, 2023 03:10
itamaro mentioned this pull request Apr 21, 2023
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itamaro commented Apr 21, 2023

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latest version of this PR resolves the issues raised on the issue. tests pass, and rerunning the benchmarks results in pretty much the same results (differences from the original impl within noise margins).

benchmarks ran using pyperformance with this patch.

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willingc commented May 1, 2023

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@gvanrossum @carljm Could you please take a quick look at this and make sure it resolved your comments? If so, we can merge. Thanks!

gvanrossum approved these changes May 1, 2023
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LGTM (assuming the refcount leak buildbots are happy). Go ahead without waiting for me with further changes!

PS. Next time please resist the urge to rebase -- it's harder to pick up a review after a rebase has happened. We squash commits when we merge them into main anyways.

carljm reviewed May 1, 2023
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LGTM barring a couple doc nits and one question.

Comment thread Doc/library/asyncio-task.rst Outdated Show resolved Hide resolved
Comment thread Lib/asyncio/tasks.py Outdated Show resolved Hide resolved
Comment thread Misc/NEWS.d/next/Library/2023-03-15-12-18-07.gh-issue-97696.DtnpIC.rst Outdated Show resolved Hide resolved
carljm reviewed May 1, 2023
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Comment thread Lib/asyncio/tasks.py Outdated Show resolved Hide resolved
carljm added the 🔨 test-with-refleak-buildbots Test PR w/ refleak buildbots; report in status section label May 1, 2023

bedevere-bot commented May 1, 2023

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🤖 New build scheduled with the buildbot fleet by @carljm for commit b17f605 🤖

If you want to schedule another build, you need to add the 🔨 test-with-refleak-buildbots label again.

bedevere-bot removed the 🔨 test-with-refleak-buildbots Test PR w/ refleak buildbots; report in status section label May 1, 2023
carljm merged commit a474e04 into python:main May 1, 2023
JelleZijlstra mentioned this pull request May 1, 2023
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carljm added a commit to carljm/cpython that referenced this pull request May 1, 2023
Merge branch 'main' into inlinecomp2 …
1274e2b
* main: (463 commits) pythongh-104057: Fix direct invocation of test_super (python#104064) pythongh-87092: Expose assembler to unit tests (python#103988) pythongh-97696: asyncio eager tasks factory (python#102853) pythongh-84436: Immortalize in _PyStructSequence_InitBuiltinWithFlags() (pythongh-104054) pythongh-104057: Fix direct invocation of test_module (pythonGH-104059) pythongh-100458: Clarify Enum.__format__() change of mixed-in types in the whatsnew/3.11.rst (pythonGH-100387) pythongh-104018: disallow "z" format specifier in %-format of byte strings (pythonGH-104033) pythongh-104016: Fixed off by 1 error in f string tokenizer (python#104047) pythonGH-103629: Update Unpack's repr in compliance with PEP 692 (python#104048) pythongh-102799: replace sys.exc_info by sys.exception in inspect and traceback modules (python#104032) Fix typo in "expected" word in few source files (python#104034) pythongh-103824: fix use-after-free error in Parser/tokenizer.c (python#103993) pythongh-104035: Do not ignore user-defined `__{get,set}state__` in slotted frozen dataclasses (python#104041) pythongh-104028: Reduce object creation while calling callback function from gc (pythongh-104030) pythongh-104036: Fix direct invocation of test_typing (python#104037) pythongh-102213: Optimize the performance of `__getattr__` (pythonGH-103761) pythongh-103895: Improve how invalid `Exception.__notes__` are displayed (python#103897) Adjust expression from `==` to `!=` in alignment with the meaning of the paragraph. (pythonGH-104021) pythongh-88496: Fix IDLE test hang on macOS (python#104025) Improve int test coverage (python#104024) ...
carljm added a commit to carljm/cpython that referenced this pull request May 2, 2023
Merge branch 'main' into cached_property_docs …
b9c39e3
* main: (760 commits) pythonGH-104102: Optimize `pathlib.Path.glob()` handling of `../` pattern segments (pythonGH-104103) pythonGH-104104: Optimize `pathlib.Path.glob()` by avoiding repeated calls to `os.path.normcase()` (pythonGH-104105) pythongh-103822: [Calendar] change return value to enum for day and month APIs (pythonGH-103827) pythongh-65022: Fix description of tuple return value in copyreg (python#103892) pythonGH-103525: Improve exception message from `pathlib.PurePath()` (pythonGH-103526) pythongh-84436: Add integration C API tests for immortal objects (pythongh-103962) pythongh-103743: Add PyUnstable_Object_GC_NewWithExtraData (pythonGH-103744) pythongh-102997: Update Windows installer to SQLite 3.41.2. (python#102999) pythonGH-103484: Fix redirected permanently URLs (python#104001) Improve assert_type phrasing (python#104081) pythongh-102997: Update macOS installer to SQLite 3.41.2. (pythonGH-102998) pythonGH-103472: close response in HTTPConnection._tunnel (python#103473) pythongh-88496: IDLE - fix another test on macOS (python#104075) pythongh-94673: Hide Objects in PyTypeObject Behind Accessors (pythongh-104074) pythongh-94673: Properly Initialize and Finalize Static Builtin Types for Each Interpreter (pythongh-104072) pythongh-104016: Skip test for deeply neste f-strings on wasi (python#104071) pythongh-104057: Fix direct invocation of test_super (python#104064) pythongh-87092: Expose assembler to unit tests (python#103988) pythongh-97696: asyncio eager tasks factory (python#102853) pythongh-84436: Immortalize in _PyStructSequence_InitBuiltinWithFlags() (pythongh-104054) ...
kumaraditya303 reviewed May 5, 2023
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Comment thread Modules/_asynciomodule.c
}
} else {
// This seems to really help performance on pyperformance benchmarks
Py_CLEAR(task->task_coro);

kumaraditya303 May 5, 2023

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Is this documented anywhere? I can't find it

itamaro May 5, 2023

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@jbower-fb

jbower-fb May 5, 2023

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See my comments on #97696.

jbower-fb May 5, 2023 •
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Also #104304 as possible documentation.

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itamaro added a commit to itamaro/cpython that referenced this pull request May 7, 2023
pythongh-97696: Use PyObject_CallMethodNoArgs and inline is_loop_runn… …
20048db
…ing check based on feedback from python#102853 (review)
itamaro mentioned this pull request May 7, 2023
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itamaro deleted the eager-tasks-factory branch May 7, 2023 22:16

willingc commented May 9, 2023

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Great to see this land @itamaro. Thanks for being so collaborative on working through the PR. 🎉

Dreamsorcerer commented Aug 8, 2024

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The proposal at the start of this thread suggested a new method or parameter for eager start. Is there a link to any discussion on why this changed? Are there plans to do something like that in future (or just to make it the default, and remove the old behaviour)?

I'm thinking about this from a library side. Changing the global task factory is inappropriate for a library to do, but we still have certain tasks that would strongly benefit from eager execution (I also wonder if a user enabling this globally could end up breaking a library that wasn't expecting eager tasks...).

So, some way to execute individual tasks eagerly would be useful (unless it simply becomes the default behaviour). We currently instantiate Task(eager_start=True) directly, though the docs seem to strongly discourage this. Adding an eager_start to asyncio.create_task(), or maybe some way to temporarily change task factories (with eager_task_factory:) would be ideal.

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Add eager task creation API to asyncio

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