Message 156690 - Python tracker

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In-reply-to
Author	vstinner
Recipients	vstinner
Date	2012年03月24日.10:44:40
SpamBayes Score	0.00031771694
Marked as misclassified	No
Message-id	<1332585881.7.0.0863389959921.issue14397@psf.upfronthosting.co.za>

Content
QueryPerformanceCounter() is not monotonic on a multiprocessor computer on Windows XP. Extract of its documentation: "Remarks On a multiprocessor computer, it should not matter which processor is called. However, you can get different results on different processors due to bugs in the basic input/output system (BIOS) or the hardware abstraction layer (HAL). To specify processor affinity for a thread, use the SetThreadAffinityMask function." See also: http://bytes.com/topic/python/answers/527849-time-clock-going-backwards time.steady(strict-True) (or "time.monotonic()"? the function name is not decided yet :§)) should use GetTickCounter64(), or GetTickCounter(). GetTickCount64() was added to Windows Seven / Server 2008. GetTickCount() overflows after 49 days. QueryPerformanceCounter() has a better resolution than GetTickCount[64]() and so it's maybe better to keep it for time.steady(strict-False)?

Content

QueryPerformanceCounter() is not monotonic on a multiprocessor computer on Windows XP. Extract of its documentation:
"Remarks
On a multiprocessor computer, it should not matter which processor is called. However, you can get different results on different processors due to bugs in the basic input/output system (BIOS) or the hardware abstraction layer (HAL). To specify processor affinity for a thread, use the SetThreadAffinityMask function." 
See also:
http://bytes.com/topic/python/answers/527849-time-clock-going-backwards
time.steady(strict-True) (or "time.monotonic()"? the function name is not decided yet :§)) should use GetTickCounter64(), or GetTickCounter().
GetTickCount64() was added to Windows Seven / Server 2008. GetTickCount() overflows after 49 days.
QueryPerformanceCounter() has a better resolution than
GetTickCount[64]() and so it's maybe better to keep it for time.steady(strict-False)?

History
Date	User	Action	Args
2012年03月24日 10:44:41	vstinner	set	recipients: + vstinner
2012年03月24日 10:44:41	vstinner	set	messageid: <1332585881.7.0.0863389959921.issue14397@psf.upfronthosting.co.za>
2012年03月24日 10:44:41	vstinner	link	issue14397 messages
2012年03月24日 10:44:40	vstinner	create

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