[Openmcl-devel] CCL 1.9 release candidate available

[Wade Humeniuk]

Scratch all that I said.  On reflection, forget about getting any awesome resolution unless you have a dedicated atomic clock,  a whole other OS and mega dollars to spend.

It seems some things are just not worth fretting over.

Wade

On 2013-02-06, at 3:08 PM, "R. Matthew Emerson" <rme at clozure.com> wrote:

> 
> On Feb 6, 2013, at 4:24 PM, Alexander Repenning <Alexander.Repenning at colorado.edu> wrote:
> 
>> 
>> On Feb 6, 2013, at 1:48 PM, R. Matthew Emerson wrote:
>> 
>>> 
>>> On Feb 6, 2013, at 3:36 PM, Alexander Repenning <alexander.repenning at Colorado.EDU> wrote:
>>> 
>>>> from the release notes:
>>>> 
>>>>> access to high-resolution clock
>>>>> 
>>>>> CCL:CURRENT-TIME-IN-NANOSECONDS returns the number of elapsed nanoseconds since some arbitrary point in time (likely system boot.)
>>>>> 
>>>> 
>>>> This sounds very useful. What is the approximate resolution of this function on Windows, i.e., what kind of Windows timer function is this based on?
>>> 
>>> Pressing M-. on current-time-in-nanoseconds leads me to its definition in ccl:lib;time.lisp.  On Windows, that function uses #_GetSystemTimeAsFileTime.
>> 
>> 
>> I was afraid of that because on most Windows systems, certainly XP, that would suggest a 15ms resolution which is rather disappointing. 
> 
> If you know of a Windows function that that would provide superior results, I'd love to hear about it.
> 
> QueryPerformanceCounter() is not a good solution.  It requires a lot of effort to compensate for its limitations.   See, for example, https://bugzilla.mozilla.org/show_bug.cgi?id=676349
> 
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