From: mcsun!uknet!cam-cl!cam-cl!gxl@uunet.uu.net (Guangxing Li)
Subject: Re: Ada delay
Date: 18 Sep 92 09:05:48 GMT [thread overview]
Message-ID: <1992Sep18.090548.20198@cl.cam.ac.uk> (raw)
_______________________
Amir Michail (amichail@plg.uwaterloo.ca) wrote:
: How is the Ada delay statement implemented? I suppose it uses a hardware
: timer coupled with a clock server, but this would mean that the time
: taken for a delay is unbounded (since we have to search an ordered list
: of tasks). If this is true, then how can one possibly use it for
: realtime scheduling of periodic tasks??
By dynamically updating the delay value, people can still have accurate
periodic tasks, even through the delay statement is not
accurate.
For example
start_time = now;
for(;;) {
load();
next_period_start = start_time + period;
start_time = next_period_start;
delay = next_period_start - now;
Ada_delay(delay);
}
next reply other threads:[~1992-09-18 9:05 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
1992-09-18 9:05 Guangxing Li [this message]
-- strict thread matches above, loose matches on Subject: below --
1992-09-21 13:43 Ada delay John Goodenough
1992-09-21 2:40 H.Shrikumar{shri@ncst.in}
1992-09-19 17:56 Gary Funck
1992-09-18 1:11 mcsun!uknet!yorkohm!minster!ken
1992-09-17 17:45 Bob Kitzberger
1992-09-17 15:04 Jorge Luis Diaz-Herrera
1992-09-17 14:26 cis.ohio-state.edu!news.sei.cmu.edu!firth
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