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!feeder.eternal-september.org!aioe.org!.POSTED.yTvCNOh9TRCAIcX40YItlQ.user.gioia.aioe.org!not-for-mail From: "Dmitry A. Kazakov" Newsgroups: comp.lang.ada Subject: Re: Competing Servers Date: Tue, 26 Mar 2019 18:03:26 +0100 Organization: Aioe.org NNTP Server Message-ID: References: <2d8df013-ed41-4b9f-8b26-b719cd2989b6@googlegroups.com> NNTP-Posting-Host: yTvCNOh9TRCAIcX40YItlQ.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 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 Content-Language: en-US X-Notice: Filtered by postfilter v. 0.9.2 Xref: reader01.eternal-september.org comp.lang.ada:55973 Date: 2019-03-26T18:03:26+01:00 List-Id: On 2019-03-26 16:50, Anh Vo wrote: > On Tuesday, March 26, 2019 at 6:11:12 AM UTC-7, Dmitry A. Kazakov wrote: >> On 2019-03-26 11:42, hnptz@yahoo.de wrote: >> >>> I want to consider any problem that can be viewed as search, and for which only one solution is required, and the problem is suitable for a data parallel approach, provided that the computation time is large enough to make the communication time negligible. >>> >>> Assume we habe s servers and n tasks. I may start with one server and n tasks. After a simple domain decomposition I want a task only search in its allocated sub-domain. When one of the tasks has found a solution: it should report it, all tasks should stop immediately and the initiating program should terminate. >>> >>> A variant from above would be to add a monitoring task, which after receiving a success message by one of the tasks, should then report and stop all tasks immediately and terminate. >> >> Usual design is a pool of worker task. A worker task takes jobs from a >> queue controlled by a protected object. The task never terminates, just >> waits for another job. Cancellation of a job is done again over a >> protected object. A worker task simply periodically checks if its >> current job were terminated. The check will propagate an exception, that >> will roll the stack with all local objects back to the main body loop >> where the task will accept the next job. > > why is an exception involved in the checking? An easy method to roll back from a deep nested call. Considering that a job solver will loop through many iterations, maybe doing recursive calls, then using a return value might be quite complicated. -- Regards, Dmitry A. Kazakov http://www.dmitry-kazakov.de