Re: [Boost-users] [Asio] io_service(std::size_t concurrency_hint) constructor

Subject: Re: [Boost-users] [Asio] io_service(std::size_t concurrency_hint) constructor
From: Gavin Lambert (gavinl_at_[hidden])
Date: 2013-12-16 17:29:06

On 17/12/2013 09:18, Quoth maks:
> In what cases using "io_service(std::size_t concurrency_hint)" ctor is more effective?
> 1. Use multiple threads - multiple io_service
> 2. Use multiple threads on one io_service object

Multiple io_services are completely independent.  The parameter is a 
hint for permissible concurrency for a single io_service being run by 
multiple threads.  What behaviour this actually affects depends on the 
platform -- for example, on Windows this is passed to the OS when 
creating the underlying IOCP, which tells it how to throttle thread wakeups.