Multithreading - 2 active running threads calling each other without blocking itself

Question

I have an implemented UDP receiver which is continuously receiving DTN packets (UDP encapsulated) and performing some operations on them. This whole process is working on a single main thread. However this consumes time on processing the packets and results in packet lost when a sender sends a huge chunk of data.

int main(int argc, char *argv[])
{
 while(1)
 {
 std::vector<char> data(64535);
 size_t len = sock->recvfrom(&data[0], maxlen, 0, fromAddress);
 // perform operation on the packets received (a bit of time consuming)
 ..................
 ..................
 }
}

I would like to use Multhithreading to overcome packets loss by moving the packet processing code to a different thread. My motive is to continuously receive packets on one thread (Thread 1) which is always running in a while loop and storing packets in a Queue (FIFO) in order to avoid loss of packets.

The other thread (Thread 2) will be doing operation on the packets received. Thread 2 should be called via event call from Thread 1 as soon as a packet is stored in a Queue.

Is the scenario even realistic? I am new with multithreading so just want to get some startup information to proceed in C++. Also if my format of asking the question is not according to standard, please let me know :)

• Robert Harvey: Have a look at Blocking Queues or the LMAX Disruptor. They both already contain the necessary concurrency mechanisms.
• k3b: This is also known as the producer consumer problem

Answer 1

Yes, your scenario is realistic.

There are queue implementations that will block a thread when it tries to retrieve an element until an element is available. With such a queue, thread 1 can just place received packets in it and thread 2 can read packets for processing as fast as they can be processed. The two threads will not block each other (except that thread 2 will get blocked if there are no packets in the queue).

• Caspian: is there an example of such Queue implementation which I could refer to?
• Bart van Ingen Schenau: @Caspian: I don't know any from the top of my head. I would suggest asking Google for one.