> > On 2/8/2022 6:42 PM, Stephen Hemminger wrote: > > On Tue, 8 Feb 2022 18:00:27 +0000 > > Ferruh Yigit <ferruh.yi...@intel.com> wrote: > > > >> On 2/8/2022 5:45 PM, Stephen Hemminger wrote: > >>> On Tue, 8 Feb 2022 13:48:00 +0000 > >>> Ciara Loftus <ciara.lof...@intel.com> wrote: > >>> > >>>> +- **Secondary Processes** > >>>> + > >>>> + Rx and Tx are not supported for secondary processes due to the > single-producer > >>>> + single-consumer nature of the AF_XDP rings. However other > operations including > >>>> + statistics retrieval are permitted. > >>>> + The maximum number of queues permitted for PMDs operating in > this model is 8 > >>>> + as this is the maximum number of fds that can be sent through the > IPC APIs as > >>>> + defined by RTE_MP_MAX_FD_NUM. > >>>> + > >>> > >>> This seems like a restriction that is true for most devices in DPDK. > >>> Most other devices also have restriction that on queues; > >>> the hardware descriptor ring can only be used by one thread at a time. > >>> Is this different with AF_XDP? > >> > >> I asked the same on v2 :) and Ciara explained the reason, it is on v2 > discussion thread. > > > > The wording of the message is what confused me. > > It would be better to change: > > due to the single-producer single-consumer nature of the AF_XDP rings > > to > > due to memory mapping of the AF_XDP rings being assigned by the > kernel > > in the primary process only. > > +1
Agree, I worded this poorly! Will submit a v4 with a more accurate explanation of the limitation. Thanks, Ciara
