[zeromq-dev] zmq_poll loop break; performance

[Chuck Remes]

On May 1, 2012, at 4:51 AM, Daniel Krikun wrote:

> Hello,
> 
> I have the following code to dispatch incoming messages via inproc transport in one thread, and to stop the dispatcher from another (main) thread:
> 
> 
> void dispatch()
> {
>       zmq::socket_t  control_socket_ ( _global_context, ZMQ_PAIR );
>       control_socket_ .connect( "inproc://control" );
> 
>      zmq::pollitem_t items[] = {
>            { data_socket_, 0, ZMQ_POLLIN, 0 },
>            {  control_socket_, 0 , ZMQ_POLLIN, 0 }
>       }; 
> 
>       while(1)
>       {
>                zmq::poll( items, 2)
>                if(items[0].revents & ZMQ_POLLIN)
>                {
>                              // ... dispatch incoming messages ..
>                }
>                if(items[1].revents & ZMQ_POLLIN)
>                      break;
>        }
> }
> 
> 
> In another (main) thread, I send an empty message to "inpoc://control" when I want to stop the dispatch.
> The problem that this stopping is somehow very slow.
> Why could be that?      
> 
> I am using zeromq-2.1.11 on Windows XP SP3, Visual Studio 2008.

Can you define what you mean by "slow?" Is it 10 milliseconds, 100 milliseconds, 1000 milliseconds, 10_000 milliseconds?

Also, is it slow *every* time?

Is it dependent upon how long the program has been running OR how many "data" messages you have dispatched?

cr