Thanks for the update! Pushed to master with small edits for clarification.
Jarno
> On Jan 6, 2017, at 1:45 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.
>
> v2: Using ovs_assert.
> v3: Fix for dumped flows missing the in_port match.
>
> Signed-off-by: Antonio Fischetti
> Signed-off-by: Bhanuprakash Bodireddy
> Co-authored-by: Bhanuprakash Bodireddy
> Signed-off-by: Jarno Rajahalme
> Co-authored-by: Jarno Rajahalme
> ---
> lib/dpif-netdev.c | 13 +
> 1 file changed, 13 insertions(+)
>
> diff --git a/lib/dpif-netdev.c b/lib/dpif-netdev.c
> index 1a47a45..4425f85 100644
> --- a/lib/dpif-netdev.c
> +++ b/lib/dpif-netdev.c
> @@ -2120,6 +2120,9 @@ dp_netdev_flow_to_dpif_flow(const struct dp_netdev_flow
> *netdev_flow,
> };
>
> miniflow_expand(_flow->cr.mask->mf, );
> +/* in_port is exact matched, but we have left it out from the mask
> for
> + * optimization reasons. Add in_port back to the mask. */
> +wc.masks.in_port.odp_port = ODPP_NONE;
>
> /* Key */
> offset = key_buf->size;
> @@ -2278,7 +2281,17 @@ dp_netdev_flow_add(struct dp_netdev_pmd_thread *pmd,
> struct dpcls *cls;
> odp_port_t in_port = match->flow.in_port.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. */
> +match->wc.masks.in_port.odp_port = 0;
> netdev_flow_mask_init(, match);
> +match->wc.masks.in_port.odp_port = ODPP_NONE;
> /* Make sure wc does not have metadata. */
> ovs_assert(!FLOWMAP_HAS_FIELD(, metadata)
>&& !FLOWMAP_HAS_FIELD(, regs));
> --
> 2.4.11
>
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