> On Jan 4, 2017, at 6:41 AM, antonio.fische...@intel.com wrote: > > This patch allows to skip the chunk comprising of dp_hash and in_port > in the subtable mask when the packet is not recirculated. This will > slightly speed up the hash computation as one expensive function call > to hash_add64() can be skipped. > For each new netdev flow we wildcard in_port in the mask, so in the > physical case where dp_hash is also wildcarded, the resulting 8-byte > chunk will not be part of the subtable mask. > > The idea behind is that all the packets within a given dpcls will > have the same in_port value and typically dp_hash == 0. So they will > have the same 8-bytes chunk in their {dp_hash, in_port} portion of the > miniflow. This doesn't contribute effectively in spreading hash values > and avoiding collisions. > > Signed-off-by: Antonio Fischetti <antonio.fische...@intel.com> > Signed-off-by: Bhanuprakash Bodireddy <bhanuprakash.bodire...@intel.com> > Co-authored-by: Bhanuprakash Bodireddy <bhanuprakash.bodire...@intel.com> > Signed-off-by: Jarno Rajahalme <ja...@ovn.org> > Co-authored-by: Jarno Rajahalme <ja...@ovn.org> > --- > lib/dpif-netdev.c | 14 +++++++++++++- > 1 file changed, 13 insertions(+), 1 deletion(-) > > diff --git a/lib/dpif-netdev.c b/lib/dpif-netdev.c > index 1a47a45..a808f4b 100644 > --- a/lib/dpif-netdev.c > +++ b/lib/dpif-netdev.c > @@ -2277,8 +2277,20 @@ dp_netdev_flow_add(struct dp_netdev_pmd_thread *pmd, > struct netdev_flow_key mask; > struct dpcls *cls; > odp_port_t in_port = match->flow.in_port.odp_port; > - > + uint32_t old_odp_port; > + > + /* As we select the dpcls based on the port number, each netdev flow > + * belonging to the same dpcls will have the same odp_port value. > + * For performance reasons here we wildcard odp_port in the mask. In the > + * physical case where dp_hash is also wildcarded, the resulting 8-byte > + * chunk {dp_hash, in_port} will be ignored by netdev_flow_mask_init() > and > + * will not be part of the subtable mask. > + * This will speed up the hash computation during dpcls_lookup() because > + * one call to hash_add64() will be skipped. */ > + old_odp_port = match->wc.masks.in_port.odp_port;
Please move this line further down in the function here and do not save the old value: ovs_assert(match->wc.masks.in_port.odp_port == ODPP_NONE); > + match->wc.masks.in_port.odp_port = 0; > netdev_flow_mask_init(&mask, match); > + match->wc.masks.in_port.odp_port = old_odp_port; And do this instead: match->wc.masks.in_port.odp_port = ODPP_NONE; > /* Make sure wc does not have metadata. */ > ovs_assert(!FLOWMAP_HAS_FIELD(&mask.mf.map, metadata) > && !FLOWMAP_HAS_FIELD(&mask.mf.map, regs)); > -- > 2.4.11 > _______________________________________________ dev mailing list d...@openvswitch.org https://mail.openvswitch.org/mailman/listinfo/ovs-dev