somenath wrote: >Rimmer, Todd wrote: > > > >>>From: Sean Hefty >>>somenath wrote: >>> >>> >>> >>> >>>>2. why is the io completion routine called when ib_poll_cq() returns >>>>zero? does this kind of notification contain any information? >>>>is there some error happening here? what are some possible problem >>>> >>>> >>>> >>>> >>>areas? >>> >>> >>> >>> >>>>any wild guess...? >>>> >>>> >>>> >>>> >>>Can you clarify what's happening? Are you calling ib_poll_cq() from >>> >>> >>> >>> >>your >> >> >> >> >>>ib_comp_handler() and not finding a completion? >>> >>> >>> >>> >>Be aware that an IB completion handler should be coded as: >> >>while poll_cq returns a completion >> process completion >>rearm CQ >> >> >> >> > >that's what I am doing, to be more specific: > >rearm CQ; >while (ib_poll_cq(cq, 1, &wc) > 0) { > process completion(); >} > >is that what you meant? > >
just to make sure I conveyed the exact thing I meant, if I change the above code as follows: while (ib_poll_cq(cq, 1, &wc) > 0) { process completion(); } rearm CQ; then I just get notification once, and don't get any futher notifications...so I assume rearm CQ should be done even if ib_poll_cq() returns zero. thanks, som. > > >>while poll_cq returns a completion >> process completion >> >>Per the IBTA spec, rearm CQ is not required to generate an event for >>completions already on the CQ, just for newly arriving ones (Mellanox >>HCAs will generate a completion event if any CQEs remain on the CQ). >> >>Due to various race situations between the HCA and the software/ULP, >>there are some valid cases where a completion event could occur after >>poll_cq has already processed the completion. >> >> >> >> > >in my case, poll_cq() always returns 0, so I never get a valid wc entry... > > > >>Todd Rimmer >> >> >> >> > > >_______________________________________________ >openib-general mailing list >openib-general@openib.org >http://openib.org/mailman/listinfo/openib-general > >To unsubscribe, please visit http://openib.org/mailman/listinfo/openib-general > > > _______________________________________________ openib-general mailing list openib-general@openib.org http://openib.org/mailman/listinfo/openib-general To unsubscribe, please visit http://openib.org/mailman/listinfo/openib-general