-----"Jason Gunthorpe" <jgg@xxxxxxxxxx> wrote: ----- >To: "Bob Pearson" <rpearsonhpe@xxxxxxxxx> >From: "Jason Gunthorpe" <jgg@xxxxxxxxxx> >Date: 10/30/2020 12:47PM >Cc: "linux-rdma@xxxxxxxxxxxxxxx" <linux-rdma@xxxxxxxxxxxxxxx> >Subject: [EXTERNAL] Re: another change breaks rxe > >On Fri, Oct 30, 2020 at 12:41:12AM -0500, Bob Pearson wrote: > >> breaks rxe because it does use IB_USER_VERBS_CMD_POST_SEND. rxe >> posts wqes to a work queue in shared memory and then calls >> ibv_post_send with zero wqes as a doorbell to the kernel which uses >> this as a hint to go read the shared memory. > >Gah, siw and rxe are open coding this stuff (wrongly!) in rdma-core > >This would be a lot better to use an eventfd > >Jason > Yes, siw does it the same. I see the hfi and ipath drivers similarly using ibv_cmd_post_send to push the wqe's (while not having them in shared mem). Do they brake as well? Do we have an example of decent eventfd usage where I could learn from how to use it? Though I think having another fd open per context might become a scaling issue. Thanks and best regards, Bernard.
