Comment créer un pool de threads en utilisant boost en C ++?

Le processus est assez simple. Commencez par créer un asio :: io_service et un thread_group. Remplissez le thread_group avec les threads liés à io_service. Assignez des tâches aux threads en utilisant la fonction boost :: bind .

Pour arrêter les threads (généralement lorsque vous quittez votre programme), arrêtez simplement io_service et rejoignez tous les threads.

Vous ne devriez avoir besoin que de ces en-têtes:

#include  #include  #include  

Voici un exemple:

 /* * Create an asio::io_service and a thread_group (through pool in essence) */ boost::asio::io_service ioService; boost::thread_group threadpool; /* * This will start the ioService processing loop. All tasks * assigned with ioService.post() will start executing. */ boost::asio::io_service::work work(ioService); /* * This will add 2 threads to the thread pool. (You could just put it in a for loop) */ threadpool.create_thread( boost::bind(&boost::asio::io_service::run, &ioService) ); threadpool.create_thread( boost::bind(&boost::asio::io_service::run, &ioService) ); /* * This will assign tasks to the thread pool. * More about boost::bind: "http://www.boost.org/doc/libs/1_54_0/libs/bind/bind.html#with_functions" */ ioService.post(boost::bind(myTask, "Hello World!")); ioService.post(boost::bind(clearCache, "./cache")); ioService.post(boost::bind(getSocialUpdates, "twitter,gmail,facebook,tumblr,reddit")); /* * This will stop the ioService processing loop. Any tasks * you add behind this point will not execute. */ ioService.stop(); /* * Will wait till all the threads in the thread pool are finished with * their assigned tasks and 'join' them. Just assume the threads inside * the threadpool will be destroyed by this method. */ threadpool.join_all(); 

Source: Recettes

Je sais que tu aimes le code.

Ma version

 namespace bamthread { typedef std::unique_ptr asio_worker; struct ThreadPool { ThreadPool(size_t threads) :service(), working(new asio_worker::element_type(service)) { while(threads--) { auto worker = boost::bind(&boost::asio::io_service::run, &(this->service)); g.add_thread(new boost::thread(worker)); } } template void enqueue(F f){ service.post(f); } ~ThreadPool() { working.reset(); //allow run() to exit g.join_all(); service.stop(); } private: boost::asio::io_service service; //< the io_service we are wrapping asio_worker working; boost::thread_group g; //< need to keep track of threads so we can join them }; } 

Morceau de code à utiliser:

 { bamthread::ThreadPool tp(n_threads); BOOST_FOREACH(int y, boost::irange(starty, endy, step)){ int im_x = 0; BOOST_FOREACH(int x, boost::irange(startx, endx, step)){ tp.enqueue (boost::bind(&camera_view_depth::threaded_intersection, this, intersections, intersected, im_x, im_y, _faces, x, y)); ++im_x; } ++im_y; } }