time.monotonic() should use a different clock source on Windows

[lunixbochs]

BPO	44328
Nosy	@pfmoore, @abalkin, @vstinner, @tjguk, @zware, @eryksun, @zooba, @pganssle, @lunixbochs

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2021-06-06.22:05:07.766>
labels = ['3.11', 'library', 'OS-windows', 'performance']
title = 'time.monotonic() should use a different clock source on Windows'
updated_at = <Date 2021-06-14.21:10:46.833>
user = 'https://github.com/lunixbochs'

bugs.python.org fields:

activity = <Date 2021-06-14.21:10:46.833>
actor = 'eryksun'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['Library (Lib)', 'Windows']
creation = <Date 2021-06-06.22:05:07.766>
creator = 'lunixbochs2'
dependencies = []
files = []
hgrepos = []
issue_num = 44328
keywords = []
message_count = 12.0
messages = ['395221', '395238', '395490', '395493', '395681', '395683', '395719', '395769', '395771', '395782', '395784', '395849']
nosy_count = 9.0
nosy_names = ['paul.moore', 'belopolsky', 'vstinner', 'tim.golden', 'zach.ware', 'eryksun', 'steve.dower', 'p-ganssle', 'lunixbochs2']
pr_nums = []
priority = 'normal'
resolution = None
stage = None
status = 'open'
superseder = None
type = 'performance'
url = 'https://bugs.python.org/issue44328'
versions = ['Python 3.11']

Linked PRs

• gh-88494: Use QueryPerformanceCounter() for time.monotonic() #116781
• gh-88494: Reduce CLOCK_RES to 1 ms in tests #118395

[lunixbochs]

Related to https://bugs.python.org/issue41299#msg395220

Presumably time.monotonic() on Windows historically used GetTickCount64() because QueryPerformanceCounter() could fail. However, that hasn't been the case since Windows XP: https://docs.microsoft.com/en-us/windows/win32/api/profileapi/nf-profileapi-queryperformancecounter

On systems that run Windows XP or later, the function will always succeed and will thus never return zero

I've run into issues with this when porting python-based applications to Windows. On other platforms, time.monotonic() was a decent precision so I used it. When I ported to Windows, I had to replace all of my time.monotonic() calls with time.perf_counter(). I would pretty much never knowingly call time.monotonic() if I knew ahead of time it could be quantized to 16ms.

My opinion is that the GetTickCount64() monotonic time code in CPython should be removed entirely and only the QueryPerformanceCounter() path should be used.

I also think some of the failure checks could be removed from QueryPerformanceCounter() / QueryPerformanceFrequency(), as they're documented to never fail in modern Windows and CPython has been dropping support for older versions of Windows, but that's less of a firm opinion.