> I'm trying to have N threads reading from the same completion channel, bounded > to M completion queues. I would like to > have N << M, and to ensure that only a single thread at time can call > ibv_poll_cq() on a given queue, to process the > events in the same order they were put in the queue. > > I can't understand how to properly achieve this, since: > 1- If I call ibv_req_notify_cq() before ibv_poll_cq(), I might end up with two > threads polling the same queue. > 2- If I call ibv_req_notify_cq() after ibv_poll_cq(), I could end up with > events in the cq not being notified in the > channel (I read this on the IBTA 11.4.2.2, and I *think* I actually > experienced this under load). > > I can use option 1 with an additional lock before ibv_req_notify_cq(), but I > would like to know if there is a simpler > way which I can't see.
I can't think of a simpler way. You just don't have any idea which CQ will be returned from the completion channel. Does your traffic pattern work to create N completion channels and distributed the CQs among them? -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
