Skip to content

GH-114911: use time.perf_counter in Stopwatch #131469

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 4 commits into from
Apr 28, 2025
Merged

GH-114911: use time.perf_counter in Stopwatch #131469

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
4 commits
Select commit Hold shift + click to select a range
e7bd81d
use time.perf_counter in Stopwatch
chris-eibl Mar 19, 2025
cdeb838
Apply suggestions from code review
chris-eibl Mar 21, 2025
39eb532
Merge branch 'main' into stopwatch
encukou Mar 21, 2025
8bf0dbc
Commit suggestion from Hugo
chris-eibl Apr 24, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
24 changes: 12 additions & 12 deletions Lib/test/support/__init__.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -2578,30 +2578,30 @@ 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
Expand Down
12 changes: 6 additions & 6 deletions Lib/test/test_int.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -588,7 +588,7 @@ 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.
Expand All @@ -603,7 +603,7 @@ 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)
Expand All @@ -613,7 +613,7 @@ 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))
Expand All @@ -628,7 +628,7 @@ 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.
Expand All @@ -640,7 +640,7 @@ 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)
Expand All @@ -650,7 +650,7 @@ 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))
Expand Down
4 changes: 2 additions & 2 deletions Lib/test/test_re.py
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -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
Expand Down Expand Up @@ -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])
Expand Down
Loading