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List:       cygwin
Subject:    Re: does usleep() sleep more than it's supposed to?
From:       "Lev Bishop" <lev.bishop () gmail ! com>
Date:       2007-02-26 14:47:05
Message-ID: ba40711f0702260647w127f2c26se19d8a002bfec14a () mail ! gmail ! com
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On 2/26/07, Carlo Florendo  wrote:
> I'm writing an application that requires time precisions up to the
> microsecond level.  However, I put a hard-coded adjustment of
> 9000 microseconds since usleep() seems to sleep on the average of
> 9000 microseconds more than it's supposed to, at least on my
> system.  I could work with up to 2000 microseconds for
> function overhead but 9000 microseconds seems to be too long.
>
> I've attached a simple test case that let's usleep() sleep at
> 100000 microseconds at each call.
>
> I've also included the output of cygcheck -svr.
>
> The output of the attached code on my system is the following:

FWIW, I don't see this:
Print elapsed time at every call to usleep()
Elapsed time (sec:microsec) 0:101000
Elapsed time (sec:microsec) 0:100000
Elapsed time (sec:microsec) 0:101000
Elapsed time (sec:microsec) 0:101000
Elapsed time (sec:microsec) 0:100000
Elapsed time (sec:microsec) 0:101000
Elapsed time (sec:microsec) 0:100000
Elapsed time (sec:microsec) 0:101000
Elapsed time (sec:microsec) 0:101000
Elapsed time (sec:microsec) 0:100000

Print elapsed after the loop()
Elapsed time (sec:microsec) 0:100000

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