Lev Bishop wrote:
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
Excellent! It seems your system has been tuned based on the
code sent by Brian Ford on this thread.
Thank you very much.
Best Regards,
Carlo
--
Carlo Florendo
Softare Engineer/Network Co-Administrator
Astra Philippines Inc.
UP-Ayala Technopark, Diliman 1101, Quezon City
Philippines
http://www.astra.ph
Member of the Astra Group of Companies
5-3-11 Sekido, Tama City
Tokyo 206-0011, Japan
http://www.astra.co.jp
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