[Stackless] Wikipedia query

Larry Dickson ldickson at cuttedge.com
Tue May 12 22:12:32 CEST 2009


Notice that the quoted concurrency definition has a self-contradiction:
"several computations are executing simultaneously" is inconsistent with
"preemptively time-shared threads on the same processor" since time-sharing
means they are broken into parts that run consecutively, taking turns, and
not simultaneously. In fact, I believe everybody means the latter, and
therefore does not require strict simultaneity. What I think is meant is
that the time-order of the computations as a whole is not required to be
determinate: they can be mixed up in any way and the results will still be
correct. (Some parts of them may be "pinned" with respect to other parts due
to a communication, however.) In this respect, tasklets surely qualify as
concurrent.

Larry Dickson

On 5/12/09, Stephan Diehl <stephan at transvection.de> wrote:
>
>
>
> Richard Tew wrote:
> [...]
> > I would say that the wikipedia entry isn't wrong as such, it is just
> > vague, and misleading because of that.  Tasklets run concurrently.
>
> I probably didn't have the right definition of 'concurrently'.
> Wikipedia says about Concurrency:
> """
> In computer science, concurrency is a property of systems in which
> several computations are executing simultaneously, and potentially
> interacting with each other. The computations may be executing on
> multiple cores in the same chip, preemptively time-shared threads on the
> same processor, or executed on physically separated processors.
> """ (http://en.wikipedia.org/wiki/Concurrency_(computer_science))
>
> In that sense, it seems to be a bit of a stretch to claim that tasklets
> run concurrently. But I'm probably nitpicking here :-)
>
> Cheers, Stephan
> [...]
> >
> > Cheers,
> > Richard.
>
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