Experimental Physics and
Industrial Control System

Kate Feng <[email protected]> · Tue, 22 Apr 2003 12:05:51 -0400

Hi Jeff,

Jeff Hill wrote:

> Hi Kate,
>
> There are certainly easy ways to compute the difference between
> two EPICS time stamps in seconds and you can also convert an
> EPICS time stamp to an enhanced struct tm (ANSI C) which includes
> the nanoseconds within a second in addition to the conventional
> date, hour, and second fields. For example, the following code
> measures the delay required to do some computationally intensive
> task and also computes the current date and time.
>
> epicsTime begin = epicsTime::getCurrent();
> .
> . something computationally intensive
> .
> // compute the delay
> double delayInSeconds = epicsTime::getCurrent() - begin;
>
> // compute the date
> local_tm_nano_sec localDAteAndTime = epicsTime::getCurrent();
>

Because  you mention this,  I wonder  what is the  finest clock
resolution
of  epicsTimerStartDelay() that I can get.  Can I  employ this technique
to
get  1 ms delay  out of   epicsTimerStartDelay() ?  If so, could you
please
explain further  about the how-to ?

>
> However, perhaps what you are after is thread sleep scheduling
> accuracy? If so, then you may be pleased with the addition of
> "double epicsThreadSleepQuantum(void)" to the epicsThread API in
> the next release of R3.14. This function returns the minimum
> sleep interval obtainable from the local OS and has been very
> useful for improving the accuracy of timers on average.
>

Yes,  epicsThreadSleepQuantum  seems to be exactly what I wanted.
I guess I can get around without it for a while.
However, when  will R3.14.2  be available ?

Many thanks,
Kate

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System