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From: Victor Porton <porton@narod.ru>
Newsgroups: comp.lang.ada
Subject: Re: Feature suggestion: different task schedules
Date: Fri, 14 Jul 2017 01:11:22 +0300
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Date: 2017-07-14T01:11:22+03:00
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Victor Porton wrote:

> Victor Porton wrote:
> 
>> I propose for Ada 2020 to add the following pragmas (and corresponding
>> aspects) for tasks and task types:
>> 
>> pragma Schedule=>Thread;
>> 
>> the regular task.
>> 
>> 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.
>> 
>> pragma Schedule=>Sometimes;
>> 
>> the task run in either of two above modes (with tasks of a task type not
>> necessarily scheduled in the same way (some may be Thread and some
>> Manual)).
>> 
>> The schedule mode may be chosen dependently on free CPU cores
>> availability to make it the fastest.
>> 
>> pragma Schedule=>Dynamic;
>> 
>> a task with this schedule may switch between Thread and Manual mode at
>> any moment of time. This is useful to use CPU cores effectively.
>> 
>> What do you think?
> 
> Hm, can a Manual task interact with any task (just like normal Thread
> task) or only with its creator task? We need to settle this question
> first.

Another solution may be to include the "parent" task in the pragma:

pragma Schedule=>Manual, Parent_Task=>...;

When calling from the parent task, we do not need to synchronize, what is 
important for compiler optimization.

Please, more ideas.

-- 
Victor Porton - http://portonvictor.org