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dpcls: Avoid one 8-byte chunk in subtable mask.

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This patch allows to skip the 8-byte chunk comprising of dp_hash and
in_port in the subtable mask when dp_hash is wildcarded.  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
typical case where dp_hash is also wildcarded, the resulting 8-byte
chunk will not be part of the subtable mask.

This manipulation of the mask is possible as the datapath classifier
is explicitly selected based on the in_port value, so that all the
datapath flows in the selected classifier have an exact match on that
in_port value.  Given this, it is safe to ignore the in_port value
when doing a lookup in the chosen classifier.

Signed-off-by: Antonio Fischetti <antonio.fischetti@intel.com>
Signed-off-by: Bhanuprakash Bodireddy <bhanuprakash.bodireddy@intel.com>
Co-authored-by: Bhanuprakash Bodireddy <bhanuprakash.bodireddy@intel.com>
Signed-off-by: Jarno Rajahalme <jarno@ovn.org>
Co-authored-by: Jarno Rajahalme <jarno@ovn.org>
This commit is contained in:
Jarno Rajahalme
2017-01-05 15:33:13 -08:00
parent fa65ca731e
commit f4b835bb0f
1 changed files with 18 additions and 2 deletions
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20
lib/dpif-netdev.c
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@@ -2101,6 +2101,9 @@ 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
* optimnization reasons. Add in_port back to the mask. */
wc.masks.in_port.odp_port = ODPP_NONE;
/* Key */
offset = key_buf->size;
@@ -2257,9 +2260,23 @@ dp_netdev_flow_add(struct dp_netdev_pmd_thread *pmd,
struct dp_netdev_flow *flow;
struct netdev_flow_key mask;
struct dpcls *cls;
/* Make sure in_port is exact matched before we read it. */
ovs_assert(match->wc.masks.in_port.odp_port == ODPP_NONE);
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 we wildcard odp_port here in the mask. In the
* typical case dp_hash is also wildcarded, and 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
* there is one less call to hash_add64() in this case. */
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));
@@ -2277,8 +2294,7 @@ dp_netdev_flow_add(struct dp_netdev_pmd_thread *pmd,
netdev_flow_key_init_masked(&flow->cr.flow, &match->flow, &mask);
/* Select dpcls for in_port. Relies on in_port to be exact match */
ovs_assert(match->wc.masks.in_port.odp_port == ODPP_NONE);
/* Select dpcls for in_port. Relies on in_port to be exact match. */
cls = dp_netdev_pmd_find_dpcls(pmd, in_port);
dpcls_insert(cls, &flow->cr, &mask);