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From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Newsgroups: comp.lang.ada
Subject: Re: =?iso-8859-1?Q?GNAT=A0and?= Tasklets
Date: Fri, 19 Dec 2014 12:01:32 +0100
Organization: cbb software GmbH
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Date: 2014-12-19T12:01:32+01:00
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On Fri, 19 Dec 2014 10:40:03 +0000 (UTC), Georg Bauhaus wrote:

> <vincent.diemunsch@gmail.com> wrote:
> 
>> It would be interesting to do a little survey on existing code using tasking.
>> I have the impression that only tasks at Library level do rendez-vous and
>> protected object synchronisation, and local tasks, most of the time, are
>> limited to a rendez-vous with their parent task at the beginning or at
>> the end. So maybe we should put restrictions on local tasks, so that we
>> can map them to jobs.
> 
> Won't the parallel loop feature be providing
> for this kind of mini job:

Parallel loop is useless for practical purposes. It wonders me why people
wasting time with this.

They could start with logical operations instead:

    X and Y

is already parallel by default. AFAIK nothing in RM forbids concurrent
evaluation of X and Y if they are independent. Same with Ada arithmetic.
E.g.

   A + B + C + D

So far no compiler evaluates arguments concurrently or vectorizes
sub-expressions like:

   A
   B  +
   C      +
   D  +

Because if they did the result would work slower than sequential code. It
simply does not worth the efforts with existing machine architectures.

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de