Re: Ada.Execution_Time

[Niklas Holsti <niklas.holsti@tidorum.invalid>]

Simon Wright wrote:
> Niklas Holsti <niklas.holsti@tidorum.invalid> writes:
> 
>> Nonsense. I spend some part of my time asleep, some time awake. Both
>> "sleeping time" and "awake time" are (pieces of) real time. A task
>> spends some of its time being executed, some of its time not being
>> executed (waiting or ready).
> 
> And, just to be clear, CPU_Time corresponds to the "awake time"?

Perhaps that is the natural choice, but I did not mean the choice to be 
significant. Dmitry was saying that "execution time" is not "time", just 
because it uses the prefix or qualification "execution". By that 
reasoning, "awake time" would not be "time", "chicken soup" would not be 
"soup", etc.

> I thought I understood pretty much what was intended in the execution
> time annex, even if it didn't seem to have much relevance to my work,
> but this discussion has managed to confuse me thoroughly.

Randy's last post in this thread, in which he agrees with Dmitry, has 
the same effect on me. I hope that further discussion with Randy will 
converge to something.

Did your earlier understanding resemble Dmitry's, or mine? Or neither?

> A minor aside -- as a user, I find the use of Time_Span here and in
> Ada.Real_Time very annoying. It's perfectly clear that what's meant is
> Duration.

I think Time_Span and Duration are different representations of the same 
physical thing, a span of time that can be physically measured in 
seconds. The reasons for having two (possibly) different representations 
(two types) have been discussed before: different requirements on range 
and precision. Still, the differences are important only for processors 
that are very small and weak, in today's scale, so perhaps this 
distinction is no longer needed and the types could be merged.

-- 
Niklas Holsti
Tidorum Ltd
niklas holsti tidorum fi
       .      @       .