Re: Competing Servers

["Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>]

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