From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00 autolearn=unavailable autolearn_force=no version=3.4.4 Path: eternal-september.org!reader01.eternal-september.org!reader02.eternal-september.org!news.eternal-september.org!news.eternal-september.org!feeder.eternal-september.org!aioe.org!.POSTED!not-for-mail From: "Dmitry A. Kazakov" Newsgroups: comp.lang.ada Subject: Re: Feature suggestion: different task schedules Date: Wed, 19 Jul 2017 09:24:45 +0200 Organization: Aioe.org NNTP Server Message-ID: References: NNTP-Posting-Host: vZYCW951TbFitc4GdEwQJg.user.gioia.aioe.org Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-Complaints-To: abuse@aioe.org User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.2.1 Content-Language: en-US X-Notice: Filtered by postfilter v. 0.8.2 Xref: news.eternal-september.org comp.lang.ada:47451 Date: 2017-07-19T09:24:45+02:00 List-Id: On 18/07/2017 22:09, Randy Brukardt wrote: > "Dmitry A. Kazakov" wrote in message > news:okkcgc$1m31$1@gioia.aioe.org... >> On 18/07/2017 02:09, Randy Brukardt wrote: > ... >>> And most important of all -- what problem >>> needs to be solved. >> >> A co-routine with task interface lacking task overhead. > > I hate to sound like a broken record, but that's a solution, not a problem. > One would need to explain what problem(s) can't be reasonably solved with > the existing features of Ada that could be solved with a co-routine. (And a > purely performance argument is by far the weakest IMHO; very few programs > are really performance bound, and most of those would value more tasking.) It is not performance argument. It is it the first line design argument (control flow inversion) as I explained in another post. I admit that I don't understand the OP proposal. It is not sufficiently described and scheduling is not single issue here. Not in the cases I have in mind. A task based solution is non-starter for two reasons. One is that it is not composable. I expect a co-routine proposal to offer a possibility to implement stacked layered protocols. I don't see how that would be possible on task basis. A protocol implementation may not be a task object. Another reason is design and OS constraints. Protocols must be handled by worker tasks. Number of tasks <<< number of connections, e.g. number of sockets. -- Regards, Dmitry A. Kazakov http://www.dmitry-kazakov.de