Speed up make_simplified_union, fix recursive tuple crash by hauntsaninja · Pull Request #15128 · python/mypy

hauntsaninja · 2023-04-25T16:21:43Z

The following code optimises make_simplified_union in the common case that there are exact duplicates in the union. In this regard, this is similar to #15104

There's a behaviour change in one unit test. I think it's good? We'll see what mypy_primer has to say.

To get this to work, I needed to use partial tuple fallbacks in a couple places (these maybe had the potential to be latent crashes anyway?) There were some interesting things going on with recursive type aliases and type state assumptions

This is about a 25% speedup on the pydantic codebase and about a 2% speedup on self check (measured with uncompiled mypy)

The following code optimises make_simplified_union in the common case that there are exact duplicates in the union. In this regard, this is similar to python#15104 To get this to work, I needed to use partial tuple fallbacks in a couple places (these maybe had the potential to be latent crashes anyway?) There were some interesting things going on with recursive type aliases and type state assumptions This is about a 25% speedup on the pydantic codebase and about a 2% speedup on self check (measured with uncompiled mypy)

for more information, see https://pre-commit.ci

hauntsaninja · 2023-04-25T17:34:10Z

Looks like there's a major performance regression in materialize

for more information, see https://pre-commit.ci

github-actions · 2023-04-25T23:59:20Z

Diff from mypy_primer, showing the effect of this PR on open source code:

pandas-stubs (https://github.com/pandas-dev/pandas-stubs) got 1.14 faster (68.0s -> 59.5s)

speedrun.com_global_scoreboard_webapp (https://github.com/Avasam/speedrun.com_global_scoreboard_webapp) got 1.24 faster (43.8s -> 35.2s)

hauntsaninja · 2023-04-26T05:22:10Z

(note to self: once this is merged, rename is_simple_literal to is_simple_str_literal or see if we can get rid of it)

JukkaL · 2023-05-03T13:39:12Z

I did a measurement using misc/perf-compare.py and this seems roughly performance-neutral for self check using a compiled mypy:

=== Results ===

hauntsaninja-msu          4.393s (0.0%)
master                    4.405s (+0.3%)

JukkaL

Looks good! I'm happy to see additional performance wins. I finally got around to reviewing this now that my jet lag is better.

Left a few additional ideas (optional, since this already seems like a nice improvement).

JukkaL · 2023-05-03T13:44:13Z

+                # If deleted subtypes had more general truthiness, use that
+                orig_item = new_items[duplicate_index]
+                if not orig_item.can_be_true and ti.can_be_true:
+                    new_items[duplicate_index] = true_or_false(orig_item)


Should we only change can_be_true, or is it ok to only adjust can_be_false?

This is a good question. I'm going to preserve the existing behaviour for now and explore this in another PR. These code paths don't have many unit tests (see #15094 and #15098), so I want to be careful here

JukkaL · 2023-05-03T13:44:21Z

+                if not orig_item.can_be_true and ti.can_be_true:
+                    new_items[duplicate_index] = true_or_false(orig_item)
+                elif not orig_item.can_be_false and ti.can_be_false:
+                    new_items[duplicate_index] = true_or_false(orig_item)


Similar to above.

hauntsaninja · 2023-05-05T20:38:02Z

This fixes a crash that just got reported #15192, so I added a regression test for it.

I added the two micro optimisations suggested.

github-actions · 2023-05-05T20:54:12Z

Diff from mypy_primer, showing the effect of this PR on open source code:

pandas-stubs (https://github.com/pandas-dev/pandas-stubs) got 1.15x faster (66.6s -> 58.0s)

speedrun.com_global_scoreboard_webapp (https://github.com/Avasam/speedrun.com_global_scoreboard_webapp) got 1.27x faster (33.3s -> 26.2s)

hauntsaninja · 2023-05-06T20:23:36Z

Nice, looks like the primer timings are pretty consistent between:
#15128 (comment)
#15128 (comment)
and some of the earlier commits on this PR (although those earlier commits had the regression on Materialize)

ilevkivskyi · 2023-05-10T14:57:13Z

This PR actually introduced a recursive tuple crash

[case testAliasRecursiveUnpack]
from typing import Tuple, TypeVar, Optional

T = TypeVar("T")
S = TypeVar("S")

A = Tuple[T, S, Optional[A[T, S]]]  # Must have two non-recursive items to crash
x: A[int, str]

*_, last = x
if last is not None:
    reveal_type(last)
[builtins fixtures/tuple.pyi]

I will check maybe there is a simple fix for it.

ilevkivskyi · 2023-05-10T15:10:00Z

It looks like there is (a bug is quite obvious). I will submit a PR shortly.

ilevkivskyi · 2023-05-10T15:44:45Z

See #15216

hauntsaninja and others added 2 commits April 25, 2023 10:18

[pre-commit.ci] auto fixes from pre-commit.com hooks

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Merge branch 'master' into msu

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hauntsaninja and others added 2 commits April 25, 2023 15:38

fix performance on materialize

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[pre-commit.ci] auto fixes from pre-commit.com hooks

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more perf

fd8463b

hauntsaninja marked this pull request as ready for review April 26, 2023 00:11

hauntsaninja mentioned this pull request Apr 26, 2023

mypy 0.990 is 1000x slow on pydantic codebase vs 0.982 #14034

Closed

JukkaL reviewed May 3, 2023

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hauntsaninja mentioned this pull request May 5, 2023

Segfault when manipulating a recursive union #15192

Closed

hauntsaninja added 2 commits May 5, 2023 13:30

add regression test for crash

b132663

micro optimisations

bc79133

hauntsaninja changed the title ~~Speed up make_simplified_union, remove a potential crash~~ Speed up make_simplified_union, fix a crash May 5, 2023

hauntsaninja changed the title ~~Speed up make_simplified_union, fix a crash~~ Speed up make_simplified_union, fix recursive tuple crash May 6, 2023

hauntsaninja merged commit 7832e1f into python:master May 6, 2023

hauntsaninja deleted the msu branch May 6, 2023 20:22

hauntsaninja mentioned this pull request Jun 14, 2023

Improve performance reports hauntsaninja/mypy_primer#81

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