Re: [Boost-users] [Threads] How to keep number of running thread constant, performing different operations

On 17/06/11 12:39, Lars Viklund wrote:

On Fri, Jun 17, 2011 at 12:20:31PM +0200, Ovanes Markarian wrote:

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On Fri, Jun 17, 2011 at 11:10 AM, Lars Viklund wrote:

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On Fri, Jun 17, 2011 at 10:12:47AM +0200, Ovanes Markarian wrote:

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On Fri, Jun 17, 2011 at 9:05 AM, Alessandro Candini wrote: [...]

For managing the N threads, you can use a thread_group.

Yes, but than you must implement and debug your own thread pool pattern. Thread group only creates a number of threads, but you need to implement the producer/consumer problem to retrieve work tasks from each thread from the queue. Now there is a choise to either use a ready thread pool or implement it yourself... AFAIK Boost has no official thread pool implementation, which is not in internal impl namespace and guarantees the interface. We have thread_group, we have Asio. One needs nothing else. I think you're misunderstanding what I suggested.

I do not consider doing this remotely bothersome, particularly as you only need features present in Boost itself.

It should need no debugging, as it's practically impossible to get wrong. If you for some reason need completion notifications from your workers, have that as part of your task, or wrap your functor in something.

---8<--- asio::io_service io; scoped_ptrasio::io_service::work work(new asio::io_service::work(io));

boost::thread_group tg; auto N = boost::thread::hardware_concurrency();

for (unsigned i = 0; i< N; ++i) tg.create_thread(boost::bind(&asio::io_service::run, boost::ref(io));

io.post(some_task); io.post(some_other_task);

// invoke io.post whenever you want to enqueue something.

// time passes, shutdown time has arrived

work.reset(); tg.join_all(); ---8<---

Could you please give me a working example as little as possible, to better understand all this stuff? -- Alessandro Candini MEEO S.r.l. Via Saragat 9 I-44122 Ferrara, Italy Tel: +39 0532 1861501 Fax: +39 0532 1861637 http://www.meeo.it ======================================== "ATTENZIONE:le informazioni contenute in questo messaggio sono da considerarsi confidenziali ed il loro utilizzo è riservato unicamente al destinatario sopra indicato. Chi dovesse ricevere questo messaggio per errore è tenuto ad informare il mittente ed a rimuoverlo definitivamente da ogni supporto elettronico o cartaceo." "WARNING:This message contains confidential and/or proprietary information which may be subject to privilege or immunity and which is intended for use of its addressee only. Should you receive this message in error, you are kindly requested to inform the sender and to definitively remove it from any paper or electronic format."