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From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Newsgroups: comp.lang.ada
Subject: Re: Feature suggestion: different task schedules
Date: Fri, 14 Jul 2017 10:37:50 +0200
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Date: 2017-07-14T10:37:50+02:00
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On 14/07/2017 07:59, Pascal Obry wrote:

>> pragma Schedule=>Manual;
>>
>> the task runs only when a protected entry is called and stops at the
>> next accept statement.
>>
>> This is usually the fastest mode in the case of one-core system.
> 
> I don't see the point. Call from the task the PO with a barrier. The
> task will be sleeping until waken-up by an event on this PO. Isn't this
> is exactly what you looking for?

The point, I presume, is to have co-routines. For that purpose the 
object used to yield processor is not even protected. All parties are 
synchronized already.

As a use-case consider a producer-consumer pair. Both would be 
pseudo-tasks backed by single thread of control (proper task).

> Don't assume you have to do optimization yourself. Most of the time the
> compiler and runtime does this for you and using the most efficient
> syscall on the target.

This is not the case for co-routines where transition of control is 
virtual, only there to use a task abstraction for decomposition of an 
algorithm that itself is strictly non-concurrent.

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