https://github.com/python/cpython/commit/11f457cf41beede182d7387080f35c73f8f4a46f
commit: 11f457cf41beede182d7387080f35c73f8f4a46f
branch: main
author: Chris Eibl <138194463+chris-e...@users.noreply.github.com>
committer: encukou <encu...@gmail.com>
date: 2025-04-28T13:55:08+02:00
summary:
GH-114911: use time.perf_counter in Stopwatch (GH-131469)
Co-authored-by: Petr Viktorin <encu...@gmail.com>
Co-authored-by: Hugo van Kemenade <1324225+hug...@users.noreply.github.com>
files:
M Lib/test/support/__init__.py
M Lib/test/test_int.py
M Lib/test/test_re.py
diff --git a/Lib/test/support/__init__.py b/Lib/test/support/__init__.py
index 146cbaaf4cb854..82f881094982f6 100644
--- a/Lib/test/support/__init__.py
+++ b/Lib/test/support/__init__.py
@@ -2586,30 +2586,30 @@ def sleeping_retry(timeout, err_msg=None, /,
delay = min(delay * 2, max_delay)
-class CPUStopwatch:
+class Stopwatch:
"""Context manager to roughly time a CPU-bound operation.
- Disables GC. Uses CPU time if it can (i.e. excludes sleeps & time of
- other processes).
+ Disables GC. Uses perf_counter, which is a clock with the highest
+ available resolution. It is chosen even though it does include
+ time elapsed during sleep and is system-wide, because the
+ resolution of process_time is too coarse on Windows and
+ process_time does not exist everywhere (for example, WASM).
- N.B.:
- - This *includes* time spent in other threads.
+ Note:
+ - This *includes* time spent in other threads/processes.
- Some systems only have a coarse resolution; check
- stopwatch.clock_info.rseolution if.
+ stopwatch.clock_info.resolution when using the results.
Usage:
- with ProcessStopwatch() as stopwatch:
+ with Stopwatch() as stopwatch:
...
elapsed = stopwatch.seconds
resolution = stopwatch.clock_info.resolution
"""
def __enter__(self):
- get_time = time.process_time
- clock_info = time.get_clock_info('process_time')
- if get_time() <= 0: # some platforms like WASM lack process_time()
- get_time = time.monotonic
- clock_info = time.get_clock_info('monotonic')
+ get_time = time.perf_counter
+ clock_info = time.get_clock_info('perf_counter')
self.context = disable_gc()
self.context.__enter__()
self.get_time = get_time
diff --git a/Lib/test/test_int.py b/Lib/test/test_int.py
index d1bf847a7a3e9f..245528ce57a146 100644
--- a/Lib/test/test_int.py
+++ b/Lib/test/test_int.py
@@ -590,7 +590,7 @@ def test_denial_of_service_prevented_int_to_str(self):
digits = 78_268
with (
support.adjust_int_max_str_digits(digits),
- support.CPUStopwatch() as sw_convert):
+ support.Stopwatch() as sw_convert):
huge_decimal = str(huge_int)
self.assertEqual(len(huge_decimal), digits)
# Ensuring that we chose a slow enough conversion to measure.
@@ -605,7 +605,7 @@ def test_denial_of_service_prevented_int_to_str(self):
with support.adjust_int_max_str_digits(int(.995 * digits)):
with (
self.assertRaises(ValueError) as err,
- support.CPUStopwatch() as sw_fail_huge):
+ support.Stopwatch() as sw_fail_huge):
str(huge_int)
self.assertIn('conversion', str(err.exception))
self.assertLessEqual(sw_fail_huge.seconds, sw_convert.seconds/2)
@@ -615,7 +615,7 @@ def test_denial_of_service_prevented_int_to_str(self):
extra_huge_int = int(f'0x{"c"*500_000}', base=16) # 602060 digits.
with (
self.assertRaises(ValueError) as err,
- support.CPUStopwatch() as sw_fail_extra_huge):
+ support.Stopwatch() as sw_fail_extra_huge):
# If not limited, 8 seconds said Zen based cloud VM.
str(extra_huge_int)
self.assertIn('conversion', str(err.exception))
@@ -630,7 +630,7 @@ def test_denial_of_service_prevented_str_to_int(self):
huge = '8'*digits
with (
support.adjust_int_max_str_digits(digits),
- support.CPUStopwatch() as sw_convert):
+ support.Stopwatch() as sw_convert):
int(huge)
# Ensuring that we chose a slow enough conversion to measure.
# It takes 0.1 seconds on a Zen based cloud VM in an opt build.
@@ -642,7 +642,7 @@ def test_denial_of_service_prevented_str_to_int(self):
with support.adjust_int_max_str_digits(digits - 1):
with (
self.assertRaises(ValueError) as err,
- support.CPUStopwatch() as sw_fail_huge):
+ support.Stopwatch() as sw_fail_huge):
int(huge)
self.assertIn('conversion', str(err.exception))
self.assertLessEqual(sw_fail_huge.seconds, sw_convert.seconds/2)
@@ -652,7 +652,7 @@ def test_denial_of_service_prevented_str_to_int(self):
extra_huge = '7'*1_200_000
with (
self.assertRaises(ValueError) as err,
- support.CPUStopwatch() as sw_fail_extra_huge):
+ support.Stopwatch() as sw_fail_extra_huge):
# If not limited, 8 seconds in the Zen based cloud VM.
int(extra_huge)
self.assertIn('conversion', str(err.exception))
diff --git a/Lib/test/test_re.py b/Lib/test/test_re.py
index f65b4076aee2c6..cf8525ed901ad3 100644
--- a/Lib/test/test_re.py
+++ b/Lib/test/test_re.py
@@ -1,7 +1,7 @@
from test.support import (gc_collect, bigmemtest, _2G,
cpython_only, captured_stdout,
check_disallow_instantiation, linked_to_musl,
- warnings_helper, SHORT_TIMEOUT, CPUStopwatch,
requires_resource)
+ warnings_helper, SHORT_TIMEOUT, Stopwatch,
requires_resource)
import locale
import re
import string
@@ -2467,7 +2467,7 @@ def test_bug_40736(self):
@requires_resource('cpu')
def test_search_anchor_at_beginning(self):
s = 'x'*10**7
- with CPUStopwatch() as stopwatch:
+ with Stopwatch() as stopwatch:
for p in r'\Ay', r'^y':
self.assertIsNone(re.search(p, s))
self.assertEqual(re.split(p, s), [s])
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