Uh oh!
There was an error while loading.Please reload this page.
- Notifications
You must be signed in to change notification settings - Fork32.4k
gh-88494: Use QueryPerformanceCounter() for time.monotonic()#116781
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.
By clicking “Sign up for GitHub”, you agree to ourterms of service andprivacy statement. We’ll occasionally send you account related emails.
Already on GitHub?Sign in to your account
Merged
Uh oh!
There was an error while loading.Please reload this page.
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.Learn more about bidirectional Unicode characters
On Windows, time.monotonic() now uses the QueryPerformanceCounter()clock to have a resolution better than 1 us, instead of thegGetTickCount64() clock which has a resolution of 15.6 ms.
MemberAuthor
vstinner commentedMar 14, 2024 • edited
Loading Uh oh!
There was an error while loading.Please reload this page.
edited
Uh oh!
There was an error while loading.Please reload this page.
Script to measure the effective clock resolution: importtimedefcompute_resolution(func):resolution=Nonepoints=0timeout=time.monotonic()+1.0previous=func()whiletime.monotonic()<timeoutorpoints<3:forloopinrange(10):t1=func()t2=func()dt=t2-t1if0<dt:breakelse:dt=t2-previousifdt<=0.0:continueifresolutionisnotNone:resolution=min(resolution,dt)else:resolution=dtpoints+=1previous=func()returnresolutiondefformat_duration(dt):ifdt>=1e-3:return"%.0f ms"% (dt*1e3)ifdt>=1e-6:return"%.0f us"% (dt*1e6)else:return"%.0f ns"% (dt*1e9)deftest_clock(name,func):print("%s:"%name)resolution=compute_resolution(func)print("- efffective resolution: %s"%format_duration(resolution))clocks= ['time','perf_counter','monotonic']fornameinclocks:func=getattr(time,name)test_clock("%s()"%name,func)info=time.get_clock_info(name)print("- implementation: %s"%info.implementation)print("- resolution: %s"%format_duration(info.resolution))print() Results before (release build): Results after (release build): monotonic() resolution changes from 15.6 ms to 100 ns: it's156,000x more accurate than before! |
vstinner added a commit to vstinner/cpython that referenced this pull requestMar 20, 2024
…ython#116781)On Windows, time.monotonic() now uses the QueryPerformanceCounter()clock to have a resolution better than 1 us, instead of thegGetTickCount64() clock which has a resolution of 15.6 ms.
adorilson pushed a commit to adorilson/cpython that referenced this pull requestMar 25, 2024
…ython#116781)On Windows, time.monotonic() now uses the QueryPerformanceCounter()clock to have a resolution better than 1 us, instead of thegGetTickCount64() clock which has a resolution of 15.6 ms.
diegorusso pushed a commit to diegorusso/cpython that referenced this pull requestApr 17, 2024
…ython#116781)On Windows, time.monotonic() now uses the QueryPerformanceCounter()clock to have a resolution better than 1 us, instead of thegGetTickCount64() clock which has a resolution of 15.6 ms.
vstinner added a commit to vstinner/distributed that referenced this pull requestMay 7, 2024
Closesdask#8641._WindowsTime is no longer needed on Windows with Python 3.13. OnWindows, Python 3.13 now uses GetSystemTimePreciseAsFileTime() fortime.time() and QueryPerformanceCounter() for time.monotonic().*python/cpython#116781*python/cpython#116822
2 tasks
fjetter pushed a commit to dask/distributed that referenced this pull requestMay 8, 2024
Closes#8641._WindowsTime is no longer needed on Windows with Python 3.13. OnWindows, Python 3.13 now uses GetSystemTimePreciseAsFileTime() fortime.time() and QueryPerformanceCounter() for time.monotonic().*python/cpython#116781*python/cpython#116822
MaxShvets commentedJan 23, 2025
@vstinner could you, please, help me figure out why the script works this way? Specifically, by taking 10 clock readings to measure |
With precise clocks such as QueryPerformanceCounter(), you don't go into the "else" block of the "for". The "else" is only there for low-resolution clocks. |
MaxShvets commentedJan 23, 2025
Got it, thanks |
Sign up for freeto join this conversation on GitHub. Already have an account?Sign in to comment
Labels
None yet
2 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Uh oh!
There was an error while loading.Please reload this page.
On Windows, time.monotonic() now uses the QueryPerformanceCounter() clock to have a resolution better than 1 us, instead of the gGetTickCount64() clock which has a resolution of 15.6 ms.
📚 Documentation preview 📚:https://cpython-previews--116781.org.readthedocs.build/