[boost] HTTP SERVER 2 Question!

I'm trying to test the HTTP SERVER 2 of the boost.asio samples. some question comes to my mind,so can anyone give me a hand? Q1. The code acceptor_(io_service_pool_.get_io_service()) means get one io_service from the pool , but to this application only one acceptor is created and one io_service is running? Q2 It takes about 25% of the CPU occupancy rate , this is caused by the Q1? zyf01234@gmail.com