From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Subject: Re: RFC: Prototype for a user threading library in Ada
Date: Mon, 20 Jun 2016 11:22:44 +0200
Date: 2016-06-20T11:22:44+02:00 [thread overview]
Message-ID: <nk8cm1$60f$1@gioia.aioe.org> (raw)
In-Reply-To: 0353aa58-328a-4abb-8101-678a379265cc@googlegroups.com
On 20/06/2016 10:23, Hadrien Grasland wrote:
> Le samedi 18 juin 2016 13:53:13 UTC+2, Dmitry A. Kazakov a écrit :
>> On 2016-06-18 11:17, Hadrien Grasland wrote:
>>
>>> But nonblocking IO is something I want to study more during the
>>> evolution of this library, as I think it is something which stresses the
>>> limits of the event model I propose. Single-shot events are a good fit
>>> when a clear notion of task completion exists, but they are less
>>> suitable when dealing with continuous processes such as streaming IO.
>>
>> You could use a pulse event instead. The event is reset when all waiting
>> tasks are released. It is not difficult to implement with protected
>> objects using entry count attribute.
>
> I am not very keen on this option because if is incompatible with
> state polling, which is useful for all kinds of non-waiting scenarios
> including component testing ("what is the state of my event after
> performing this operation?").
If you know the tasks awaiting a pulse event you could make it
compatible again by polling for event + task states. But since the
environment is not really concurrent there is nothing to worry about.
You cannot have a race condition within just one task.
>>> I do not want to go in the direction of reusable events, as the
>>> amount of ways these can go wrong is all but infinite, however there has to be
>> a better synchronization primitive for this kind of progressive evolution..
>>
>> One solution is to have more states than Reset/Signaled. An event can
>> traverse a larger set of states being a small state machine. As well as
>> transitions may be initiated not only explicitly but also through
>> scheduling events, e.g. task release in case of the pulse event.
>
> Would you mean something like, for example, a discrete or
> floating-point progress counter that can be programmed to fire an event
> when going above any arbitrary level of progress?
That too. But generally for a client a possibility to wait for any of
the states or for any disjunction of states.
--
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de
next prev parent reply other threads:[~2016-06-20 9:22 UTC|newest]
Thread overview: 72+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-17 9:44 RFC: Prototype for a user threading library in Ada Hadrien Grasland
2016-06-17 16:18 ` Niklas Holsti
2016-06-17 16:46 ` Dmitry A. Kazakov
2016-06-18 8:16 ` Hadrien Grasland
2016-06-18 8:47 ` Dmitry A. Kazakov
2016-06-18 9:17 ` Hadrien Grasland
2016-06-18 11:53 ` Dmitry A. Kazakov
2016-06-20 8:23 ` Hadrien Grasland
2016-06-20 9:22 ` Dmitry A. Kazakov [this message]
2016-06-23 1:42 ` Randy Brukardt
2016-06-23 8:39 ` Dmitry A. Kazakov
2016-06-23 22:12 ` Randy Brukardt
2016-06-24 7:34 ` Dmitry A. Kazakov
2016-06-24 23:00 ` Randy Brukardt
2016-06-25 7:11 ` Dmitry A. Kazakov
2016-06-26 2:02 ` rieachus
2016-06-26 6:26 ` Dmitry A. Kazakov
2016-06-24 0:38 ` rieachus
2016-06-25 6:28 ` Dmitry A. Kazakov
2016-06-26 1:34 ` rieachus
2016-06-26 3:21 ` Randy Brukardt
2016-06-26 6:15 ` Dmitry A. Kazakov
2016-06-28 20:44 ` Anh Vo
2016-07-02 4:13 ` Randy Brukardt
2016-07-02 10:25 ` Dmitry A. Kazakov
2016-07-05 21:53 ` Randy Brukardt
2016-07-06 9:25 ` Dmitry A. Kazakov
2016-07-07 0:32 ` Randy Brukardt
2016-07-07 6:08 ` Niklas Holsti
2016-07-08 0:03 ` Randy Brukardt
2016-07-08 7:32 ` Dmitry A. Kazakov
2016-07-11 19:40 ` Randy Brukardt
2016-07-12 8:37 ` Dmitry A. Kazakov
2016-07-12 21:31 ` Randy Brukardt
2016-07-08 20:17 ` Niklas Holsti
2016-06-24 21:06 ` Hadrien Grasland
2016-06-26 3:09 ` Randy Brukardt
2016-06-26 6:41 ` Dmitry A. Kazakov
2016-07-02 4:21 ` Randy Brukardt
2016-07-02 10:33 ` Dmitry A. Kazakov
2016-07-05 21:24 ` Randy Brukardt
2016-07-06 13:46 ` Dmitry A. Kazakov
2016-07-07 1:00 ` Randy Brukardt
2016-07-07 14:23 ` Dmitry A. Kazakov
2016-07-07 23:43 ` Randy Brukardt
2016-07-08 8:23 ` Dmitry A. Kazakov
2016-07-11 19:44 ` Randy Brukardt
2016-06-26 9:09 ` Hadrien Grasland
2016-07-02 4:36 ` Randy Brukardt
2016-07-02 5:30 ` Simon Wright
2016-07-05 21:29 ` Randy Brukardt
2016-07-02 11:13 ` Hadrien Grasland
2016-07-02 13:18 ` Dmitry A. Kazakov
2016-07-02 16:49 ` Hadrien Grasland
2016-07-02 21:33 ` Niklas Holsti
2016-07-03 20:56 ` Hadrien Grasland
2016-07-02 17:26 ` Niklas Holsti
2016-07-02 21:14 ` Niklas Holsti
2016-07-03 7:42 ` Hadrien Grasland
2016-07-03 8:39 ` Dmitry A. Kazakov
2016-07-03 21:15 ` Hadrien Grasland
2016-07-04 7:44 ` Dmitry A. Kazakov
2016-07-05 21:38 ` Randy Brukardt
2016-06-21 2:40 ` rieachus
2016-06-21 7:34 ` Dmitry A. Kazakov
2016-06-18 7:56 ` Hadrien Grasland
2016-06-18 8:33 ` Hadrien Grasland
2016-06-18 11:38 ` Hadrien Grasland
2016-06-18 13:17 ` Niklas Holsti
2016-06-18 16:27 ` Jeffrey R. Carter
2016-06-20 8:42 ` Hadrien Grasland
2016-07-10 0:45 ` rieachus
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