On Thu, Jun 03, 2021 at 01:52:38AM +0100, Nguyen, Anthony L wrote: > On Tue, 2021-06-01 at 13:32 +0200, Maciej Fijalkowski wrote: > > Under rare circumstances there might be a situation where a > > requirement > > of having a XDP Tx queue per core could not be fulfilled and some of > > the > > Tx resources would have to be shared between cores. This yields a > > need > > for placing accesses to xdp_rings array onto critical section > > protected > > by spinlock. > > > > Design of handling such scenario is to at first find out how many > > queues > > are there that XDP could use. Any number that is not less than the > > half > > of a count of cores of platform is allowed. XDP queue count < cpu > > count > > is signalled via new VSI state ICE_VSI_XDP_FALLBACK which carries the > > information further down to Rx rings where new ICE_TX_XDP_LOCKED is > > set > > based on the mentioned VSI state. This ring flag indicates that > > locking > > variants for getting/putting xdp_ring need to be used in fast path. > > > > For XDP_REDIRECT the impact on standard case (one XDP ring per CPU) > > can > > be reduced a bit by providing a separate ndo_xdp_xmit and swap it at > > configuration time. However, due to the fact that net_device_ops > > struct > > is a const, it is not possible to replace a single ndo, so for the > > locking variant of ndo_xdp_xmit, whole net_device_ops needs to be > > replayed. > > > > It has an impact on performance (1-2 %) of a non-fallback path as > > branches are introduced. > > > > Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@xxxxxxxxx> > > --- > > drivers/net/ethernet/intel/ice/ice.h | 37 +++++++++ > > drivers/net/ethernet/intel/ice/ice_base.c | 5 ++ > > drivers/net/ethernet/intel/ice/ice_lib.c | 4 +- > > drivers/net/ethernet/intel/ice/ice_main.c | 76 > > ++++++++++++++++++- > > drivers/net/ethernet/intel/ice/ice_txrx.c | 62 ++++++++++++++- > > drivers/net/ethernet/intel/ice/ice_txrx.h | 2 + > > drivers/net/ethernet/intel/ice/ice_txrx_lib.c | 13 +++- > > 7 files changed, 191 insertions(+), 8 deletions(-) > > This isn't applying to next-queue/dev-queue. I believe it's becuase the > branch has the soon to be sent tracing patch from Magnus [1]. Thanks for a heads up Tony, I'll send rebased revision. > > Thanks, > Tony > > [1] https://patchwork.ozlabs.org/project/intel-wired- > lan/patch/20210510093854.31652-3-magnus.karlsson@xxxxxxxxx/
