Ada DELAY statement accuracy?

Ada DELAY statement accuracy?

[Jeff Motes]

I need an Ada Delay routine that is accurate to 1 ms.  The Ada DELAY doesn't 
appear to do this. Anyone have any suggestions?

Re: Ada DELAY statement accuracy?

[Arthur Evans Jr]

In article <5cir31$q5d@mic14.redstone.army.mil>
jmotes@sed.redstone.army.mil (Jeff Motes) writes:

> I need an Ada Delay routine that is accurate to 1 ms.  The Ada DELAY doesn't 
> appear to do this. Anyone have any suggestions?

The question isn't really meaningful.

The semantics of delay in 9.6(20-21) calls for blocking the task issuing
it until a specific time, after which the task is then eligible to run.
Will it start running then, or within 1 ms of then?  Nothing in Ada's
definition says.  It depends at least on what other tasks are then
running, their priority, and the priority of the task issuing the delay.
There can be no upper bound on how long the task will delay.

Looking at it another way, if two tasks both execute a 'delay until'
with the same target time, then (on a uni-processor) they obviously
can't both start at that time.  And if the task that happens to start
first has higher priority than the other, the other can wait arbitrarily
long.

Perhaps you can restate your question so as to make more clear what you
want.

Art Evans

Arthur Evans Jr, PhD        Phone: 412-963-0839
Ada Consulting              FAX:   412-963-0927
461 Fairview Road
Pittsburgh PA  15238-1933
evans@evans.pgh.pa.us

Re: Ada DELAY statement accuracy?

[Jim Hopper]

In article <5cir31$q5d@mic14.redstone.army.mil>
jmotes@sed.redstone.army.mil (Jeff Motes) writes:

> I need an Ada Delay routine that is accurate to 1 ms.  The Ada DELAY doesn't 
> appear to do this. Anyone have any suggestions?

on what platform!  answer is different depending upon platform.

jim