Multithreading

[anarthal]

We currently run a single-threaded io_context. Consider how we can make it multi-threaded (one context per thread vs. multiple threads and one context).

[mzimbres]

My suggestion here is to use share-nothing io_contexts, the exact number will depend on the number of CPU cores available, so it would be good to make this a command like parameter. To be able to have one listener per io_context listening on the same port, you have the set SO_REUSEPORT like this

   int one = 1;
   auto const ret =
      setsockopt( acceptor_.native_handle()
                , SOL_SOCKET
                , SO_REUSEPORT
                , &one, sizeof(one));

   if (ret == -1) {
      log::write( log::level::err
                , "Unable to set socket option SO_REUSEPORT: {0}"
                , strerror(errno));
   }