Hi Damjan and all, We are currently thinking of how to utilize the handoff mechanism to serve our application logic – to run a packet re-ordering and re-transmit queue in the same worker context to avoid any lock between threads. We come across with a question when looking into the implementation of handoff. Hope you can figure it out for us.
In vlib_get_worker_handoff_queue_elt -> vlib_get_frame_queue_elt : /* Wait until a ring slot is available */ while (new_tail >= fq->head_hint + fq->nelts) vlib_worker_thread_barrier_check (); We understand that the worker has wait for the any available slot from the other worker before putting buffer into it. Then the question is: is it a potential dead lock that two workers waiting for each other? F.g., Worker A and B, A is going to handoff to B but unfortunately at the same time B has the same thing to do to A, then they are both waiting forever. If it is true, is it better to drop the packet when the ring is full? I copied my colleague Lollita into this discussion, she is working on it and knows better about this hypothesis. Regards, Kingwel
