Reported resolution of `time.process_time` and `time.thread_time` is wrong on Windows
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Description
Bug report
Bug description:
>>> import time
>>> time.get_clock_info("process_time")
namespace(implementation='GetProcessTimes()', monotonic=True, adjustable=False, resolution=1e-07)
>>> time.get_clock_info("thread_time")
namespace(implementation='GetThreadTimes()', monotonic=True, adjustable=False, resolution=1e-07)
The reported resolution=1e-07 is way off. According to @eryksun in https://github.com/python/cpython/issues/82040#issuecomment-1093831784
Don't read too much into the clock info here:
Process times [1] are stored as a 64-bit integer in units of 100 ns (1e-7). But the kernel schedules threads based on a timer that ticks every 15.625 ms by default. It can be lowered to about 0.5 ms, but this degrades battery life.
This has also caused problems in test_int.test_denial_of_service, see https://github.com/python/cpython/issues/114911#issuecomment-2567094984.
I suggest to report 15.625 ms, since this is the upper limit.
CPython versions tested on:
CPython main branch
Operating systems tested on:
Windows
Linked PRs
- gh-135305
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Begin by reviewing linked PR gh-135305 and the behavior of time.get_clock_info("process_time") and time.get_clock_info("thread_time") on Windows. Check test_int.test_denial_of_service for the related impact; done means the reported resolutions reflect the intended Windows timing behavior and the affected test passes.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- python
- Domain
- operating-systems
- Issue type
- Bug
- Difficulty
- 3/5
- Estimated time
- 1-2 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 25/100