[ovs-dev] [PATCH v3] dpcls: Avoid one 8-byte chunk in subtable mask.
Fischetti, Antonio
antonio.fischetti at intel.com
Tue Jan 10 10:50:01 UTC 2017
Hi Jarno,
I've run make check with and without this patch and I got the same results.
For both cases the 'dpif-netdev' and 'flow classifier' unit-tests were ok.
For both cases I got the same failures on
977: PMD - stats FAILED (pmd.at:198)
and many IPv6 tests like
1095: ofproto-dpif - sFlow packet sampling - IPv6 collector FAILED (ofproto-dpif.at:5769)
1134: ofproto-dpif megaflow - netflow - IPv6 collector FAILED (ofproto-dpif.at:7319)
...
Thanks,
Antonio
> -----Original Message-----
> From: Fischetti, Antonio
> Sent: Friday, January 6, 2017 9:45 AM
> To: dev at openvswitch.org
> Cc: jarno at ovn.org; Bodireddy, Bhanuprakash
> <bhanuprakash.bodireddy at intel.com>; Fischetti, Antonio
> <antonio.fischetti at intel.com>
> Subject: [PATCH v3] dpcls: Avoid one 8-byte chunk in subtable mask.
>
> 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 <antonio.fischetti at intel.com>
> Signed-off-by: Bhanuprakash Bodireddy <bhanuprakash.bodireddy at intel.com>
> Co-authored-by: Bhanuprakash Bodireddy <bhanuprakash.bodireddy at intel.com>
> Signed-off-by: Jarno Rajahalme <jarno at ovn.org>
> Co-authored-by: Jarno Rajahalme <jarno at ovn.org>
> ---
> 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(&netdev_flow->cr.mask->mf, &wc.masks);
> + /* 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(&mask, match);
> + 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
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