what is the best design(ipc)
 

I have the daemon connected to the device driver(server). I have several processes(clients). All clients are talking to the server. The server can talk to each client as well as send a broadcast message to all clients. What architecture would you suggest and why? High performance is a must. This is low resources embedded SBC. Simplified code example is appreciated.
Thanks.

Have you considered using sockets? You'd have to use local-domain sockets (AF_UNIX or AF_LOCAL (same thing)) for high performance. These can only be used locally and are represented as a node in the filesystem. They're nice, because if you ever chose to allow access across the network (via sockets w/ AF_INET), it'll be simple to implement, but you get the benefit of having local IPC speeds for local processes.

Sure I have! That is why I'm calling processes server and client. The case is when I need to broadcast, I'll have to send the same message to each client as many times as number of clients I have. And some other draw back does exist.