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GeezerVison is showing github.com — bpo-45953: Statically allocate the main interpreter (and initial thread state). by ericsnowcurrently · Pull Request #29883 · python/cpython

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@ericsnowcurrently

@ericsnowcurrently ericsnowcurrently commented Dec 1, 2021 •
edited by bedevere-bot
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Currently the main interpreter is allocated on the heap during runtime initialization. Here we are instead embedding it into _PyRuntimeState, which means it is statically allocated as part of the _PyRuntime global. The same goes for the initial thread state (of each interpreter, including the main one). Consequently there are fewer allocations during runtime/interpreter init, fewer possible failures, and better memory locality.

FYI, this also helps efforts to consolidate globals, which in turns helps work on subinterpreter isolation.

https://bugs.python.org/issue45953

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ericsnowcurrently added 11 commits December 1, 2021 10:54
@ericsnowcurrently
Return void from _PyEval_InitState().
5e6eda9
@ericsnowcurrently
Fix a memory leak.
de12b98
@ericsnowcurrently
Move thread-related interpreter state into a sub-struct.
035eff3
@ericsnowcurrently
Factor out init_threadstate().
1569a53
@ericsnowcurrently
Do not initialize a thread state if already initialized.
518e3f3
@ericsnowcurrently
Avoid allocating the first thread state.
9995a84
@ericsnowcurrently
Factor out init_interpreter().
f22d0da
@ericsnowcurrently
Preallocate the main interpreter.
cf39d57
@ericsnowcurrently
Add a note about expectations for init_interpreter().
b840213
@ericsnowcurrently
Add a NEWS entry.
3bf69b0
@ericsnowcurrently
Add _PyInterpreterState_Main().
4de466e
@ericsnowcurrently
ericsnowcurrently requested a review from markshannon as a code owner December 1, 2021 19:30
@the-knights-who-say-ni the-knights-who-say-ni added the CLA signed label Dec 1, 2021
@bedevere-bot bedevere-bot added the awaiting core review label Dec 1, 2021
@ericsnowcurrently ericsnowcurrently mentioned this pull request Dec 1, 2021
Use member non-pointer declarations in Py*State structs instead of heap-allocated pointers. faster-cpython/ideas#79
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markshannon
markshannon reviewed Dec 2, 2021
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Comment thread Python/ceval.c
int
_PyEval_InitState(struct _ceval_state *ceval)
void
_PyEval_InitState(struct _ceval_state *ceval, PyThread_type_lock pending_lock)

@markshannon markshannon Dec 2, 2021

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Would this be a good opportunity to remove this function?
The _pending_calls struct belongs on the interpreter state, not on the ceval as only the main interpreter can handle them.

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@ericsnowcurrently ericsnowcurrently Dec 2, 2021

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There's enough going on in this PR that I'd rather not.

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markshannon
markshannon reviewed Dec 2, 2021
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Comment thread Modules/posixmodule.c Resolved

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markshannon
markshannon reviewed Dec 2, 2021
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Comment thread Modules/posixmodule.c Resolved

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markshannon
markshannon requested changes Dec 2, 2021
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A couple of tests have been inverted.

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@bedevere-bot bedevere-bot removed the awaiting core review label Dec 2, 2021
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bedevere-bot commented Dec 2, 2021

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When you're done making the requested changes, leave the comment: I have made the requested changes; please review again.
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@bedevere-bot bedevere-bot added the awaiting changes label Dec 2, 2021
ericsnowcurrently added 8 commits December 2, 2021 16:43
@ericsnowcurrently
Fix a check for the main interpreter.
9bb32a6
@ericsnowcurrently
Ensure no subinterpreters are created until after the main interprete…
385f298 
…r is.
@ericsnowcurrently
Make sure the interpreter is fully initialized.
354997f
@ericsnowcurrently
Use PyMem_RawCalloc() to allocate thread states.
9bbf8a0
@ericsnowcurrently
Make sure the thread state is fully initialized.
8d1cf35
@ericsnowcurrently
Clear the preallocated states when "deleted".
188aed8
@ericsnowcurrently
Statically initialize the "preallocated" states.
e0da483
@ericsnowcurrently
Fix a typo.
46c7767
markshannon
markshannon reviewed Jan 10, 2022
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Comment thread Include/cpython/pystate.h Resolved

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Comment thread Include/internal/pycore_interp.h Resolved

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Comment thread Include/internal/pycore_interp.h Outdated
} _preallocated;
};

#define _PyInterpreterState_INIT \

@markshannon markshannon Jan 10, 2022

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This is only used once, please remove it.

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@ericsnowcurrently ericsnowcurrently Jan 11, 2022

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FYI, I brought this back to avoid so much nesting and clutter in _PyRuntimeState_INIT.

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Comment thread Include/internal/pycore_runtime.h Resolved

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Comment thread Include/internal/pycore_runtime.h Resolved

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Comment thread Include/internal/pycore_runtime.h
} _preallocated;
} _PyRuntimeState;

#define _PyRuntimeState_INIT \

@markshannon markshannon Jan 10, 2022

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Might as well remove this as well. It is also only used once.

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@ericsnowcurrently ericsnowcurrently Jan 10, 2022

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Should _Py_global_objects_INIT also move? It's pretty big and likely to get much bigger.

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@ericsnowcurrently ericsnowcurrently Jan 10, 2022 •
edited
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Actually, _PyRuntimeState_INIT is used twice.

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ericsnowcurrently added 5 commits January 10, 2022 13:55
@ericsnowcurrently
Fold _PyThreadState_INIT into _PyInterpreterState_INIT.
5b34b42
@ericsnowcurrently
Fold _PyInterpreterState_INIT into _PyRuntimeState_INIT.
837bfe6
@ericsnowcurrently
Drop PyThreadState._preallocated.
ebefa35
@ericsnowcurrently
tstate -> initial_thread.
eb7a080
@ericsnowcurrently
Mirror the top-level structure in _preallocated.
1ef4a39
@ericsnowcurrently
ericsnowcurrently requested a review from markshannon January 11, 2022 00:16
ericsnowcurrently added 13 commits January 11, 2022 09:41
@ericsnowcurrently
Merge branch 'main' into preallocate-main
771e574
@ericsnowcurrently
Clarify some comments.
b5c43f1
@ericsnowcurrently
Fold in _PyRuntimeState._preallocated.
bfc3906
@ericsnowcurrently
Make "initial" const.
9b25c8b
@ericsnowcurrently
Fold in PyInterpreterState._preallocated.
e776c31
@ericsnowcurrently
Move the initial thread to the bottom of PyInterpreterState.
c6bda1f
@ericsnowcurrently
Split up _PyRuntimeState_INIT for less nesting and clutter.
8ab6261
@ericsnowcurrently
Fix a comment.
ff8de28
@ericsnowcurrently
Move the main interpreter to the bottom of _PyRuntimeState.
b28afb3
@ericsnowcurrently
Clarify some comments.
0d30300
@ericsnowcurrently
Add a comment for the _static field.
e193794
@ericsnowcurrently
Move the comments about pre-allocated data down.
e9f1262
@ericsnowcurrently
Fix a typo.
a6a6471
@ericsnowcurrently

ericsnowcurrently commented Jan 12, 2022

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With basically all feedback addressed I plan on merging this soon, to unblock other changes I have waiting. If I missed something, I'd be glad to address it in a follow-up PR.
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@gvanrossum

gvanrossum commented Jan 12, 2022 via email

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Fine with me.
…
On Wed, Jan 12, 2022 at 2:56 PM Eric Snow ***@***.***> wrote: With basically all feedback addressed I plan on merging this soon, to unblock other changes I have waiting. If I missed something, I'd be glad to address it in a follow-up PR. — Reply to this email directly, view it on GitHub <#29883 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAWCWMXNEYDUC6YIRLTJAEDUVYBIXANCNFSM5JFJMYAA> . Triage notifications on the go with GitHub Mobile for iOS <https://apps.apple.com/app/apple-store/id1477376905?ct=notification-email&mt=8&pt=524675> or Android <https://play.google.com/store/apps/details?id=com.github.android&referrer=utm_campaign%3Dnotification-email%26utm_medium%3Demail%26utm_source%3Dgithub>. You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>
-- --Guido van Rossum (python.org/~guido)
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@ericsnowcurrently
ericsnowcurrently merged commit ed57b36 into python:main Jan 12, 2022
@bedevere-bot bedevere-bot removed the awaiting change review label Jan 12, 2022
@ericsnowcurrently
ericsnowcurrently deleted the preallocate-main branch January 12, 2022 23:28
tacaswell added a commit to tacaswell/typed_ast that referenced this pull request Jan 25, 2022
@tacaswell
FIX: Account form stdbool.h being included in Python.h
9b849ca 
As of CPython 3.11 (via python/cpython#29883) stdbool.h
is now included in Python.h so do attempt to redefine bool/true/false.
@tacaswell tacaswell mentioned this pull request Jan 25, 2022
FIX: Account form stdbool.h being included in Python.h python/typed_ast#184
Merged
srittau pushed a commit to python/typed_ast that referenced this pull request Jan 25, 2022
@tacaswell
FIX: Account form stdbool.h being included in Python.h (#184)
36110cf 
As of CPython 3.11 (via python/cpython#29883) stdbool.h
is now included in Python.h so do attempt to redefine bool/true/false.
@ericsnowcurrently ericsnowcurrently mentioned this pull request Nov 8, 2022
Statically allocate interpreter states as much as possible. #90111
Closed
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@ericsnowcurrently @bedevere-bot @markshannon @gvanrossum @arhadthedev @the-knights-who-say-ni
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