[ovs-dev] [PATCH v2] lib/classifier: Use a prefix tree to optimize ports wildcarding.
Ethan Jackson
ethan at nicira.com
Wed Apr 16 21:28:02 UTC 2014
Acked-by: Ethan Jackson <ethan at nicira.com>
I suppose my only worry with this is if we should hold off until the
exact match cache is added to the linux kernel datapath as well . . .
Ethan
On Mon, Apr 14, 2014 at 1:14 PM, Jarno Rajahalme <jrajahalme at nicira.com> wrote:
> This should optimize port masks for megaflows for typical port usage
> in matches. Each subtable has it's own trie if the subtable matches
> any of the ports bits. This trie is consulted only after failing
> lookup to determine the number of bits that needs to be unwildcarded
> to guarantee that any packet that should match on any of the other
> rules will NOT match this megaflow.
>
> This version is not configurable and is always on.
>
> Signed-off-by: Jarno Rajahalme <jrajahalme at nicira.com>
> ---
> v2: Rebase to master.
>
> lib/classifier.c | 90 +++++++++++++++++++++++++++++++++++++++++++++++----
> lib/classifier.h | 2 ++
> tests/classifier.at | 6 ++--
> 3 files changed, 89 insertions(+), 9 deletions(-)
>
> diff --git a/lib/classifier.c b/lib/classifier.c
> index 55ca5ea..ef20bd1 100644
> --- a/lib/classifier.c
> +++ b/lib/classifier.c
> @@ -30,6 +30,10 @@
>
> VLOG_DEFINE_THIS_MODULE(classifier);
>
> +/* Ports trie depends on both ports sharing the same ovs_be32. */
> +#define TP_PORTS_OFS32 (offsetof(struct flow, tp_src) / 4)
> +BUILD_ASSERT_DECL((offsetof(struct flow, tp_dst) / 4) == TP_PORTS_OFS32);
> +
> struct trie_ctx;
> static struct cls_subtable *find_subtable(const struct classifier *,
> const struct minimask *);
> @@ -71,10 +75,16 @@ static void trie_init(struct classifier *, int trie_idx,
> const struct mf_field *);
> static unsigned int trie_lookup(const struct cls_trie *, const struct flow *,
> unsigned int *checkbits);
> -
> +static unsigned int trie_lookup_value(const struct trie_node *,
> + const ovs_be32 value[],
> + unsigned int *checkbits);
> static void trie_destroy(struct trie_node *);
> static void trie_insert(struct cls_trie *, const struct cls_rule *, int mlen);
> +static void trie_insert_prefix(struct trie_node **, const ovs_be32 *prefix,
> + int mlen);
> static void trie_remove(struct cls_trie *, const struct cls_rule *, int mlen);
> +static void trie_remove_prefix(struct trie_node **, const ovs_be32 *prefix,
> + int mlen);
> static void mask_set_prefix_bits(struct flow_wildcards *, uint8_t be32ofs,
> unsigned int nbits);
> static bool mask_prefix_bits_set(const struct flow_wildcards *,
> @@ -389,6 +399,23 @@ classifier_replace(struct classifier *cls, struct cls_rule *rule)
> trie_insert(&cls->tries[i], rule, subtable->trie_plen[i]);
> }
> }
> +
> + /* Ports trie. */
> + if (subtable->ports_mask_len) {
> + ovs_be32 ports, mask, masked_ports;
> +
> + /* We mask the value to be inserted to always have the wildcarded
> + * bits in known (zero) state, so we can include them in comparison
> + * and they will always match (== their original value does not
> + * matter). */
> + ports = (OVS_FORCE ovs_be32)miniflow_get(&rule->match.flow,
> + TP_PORTS_OFS32);
> + mask = minimask_get(&subtable->mask, TP_PORTS_OFS32);
> + masked_ports = ports & mask;
> +
> + trie_insert_prefix(&subtable->ports_trie, &masked_ports,
> + subtable->ports_mask_len);
> + }
> } else {
> rule->partition = old_rule->partition;
> }
> @@ -421,6 +448,17 @@ classifier_remove(struct classifier *cls, struct cls_rule *rule)
>
> subtable = find_subtable(cls, &rule->match.mask);
>
> + if (subtable->ports_mask_len) {
> + ovs_be32 ports, mask, masked_ports;
> +
> + ports = (OVS_FORCE ovs_be32)miniflow_get(&rule->match.flow,
> + TP_PORTS_OFS32);
> + mask = minimask_get(&subtable->mask, TP_PORTS_OFS32);
> + masked_ports = ports & mask;
> +
> + trie_remove_prefix(&subtable->ports_trie,
> + &masked_ports, subtable->ports_mask_len);
> + }
> for (i = 0; i < cls->n_tries; i++) {
> if (subtable->trie_plen[i]) {
> trie_remove(&cls->tries[i], rule, subtable->trie_plen[i]);
> @@ -859,6 +897,11 @@ insert_subtable(struct classifier *cls, const struct minimask *mask)
> cls->tries[i].field);
> }
>
> + /* Ports trie. */
> + subtable->ports_trie = NULL;
> + subtable->ports_mask_len = 32
> + - ctz32(ntohl((OVS_FORCE ovs_be32)minimask_get(mask, TP_PORTS_OFS32)));
> +
> return subtable;
> }
>
> @@ -867,6 +910,9 @@ destroy_subtable(struct classifier *cls, struct cls_subtable *subtable)
> {
> int i;
>
> + /* Port tries. */
> + trie_destroy(subtable->ports_trie);
> +
> for (i = 0; i < subtable->n_indices; i++) {
> hindex_destroy(&subtable->indices[i]);
> }
> @@ -1121,6 +1167,23 @@ find_match_wc(const struct cls_subtable *subtable, const struct flow *flow,
> * but it didn't match. */
> rule = NULL;
> }
> + if (!rule && subtable->ports_mask_len) {
> + /* Ports are always part of the final range, if any.
> + * No match was found for the ports. Use the ports trie to figure out
> + * which ports bits to unwildcard. */
> + unsigned int mbits;
> + ovs_be32 value, mask;
> +
> + mask = minimask_get(&subtable->mask, TP_PORTS_OFS32);
> + value = ((ovs_be32 *)flow)[TP_PORTS_OFS32] & mask;
> + trie_lookup_value(subtable->ports_trie, &value, &mbits);
> +
> + ((ovs_be32 *)&wc->masks)[TP_PORTS_OFS32] |=
> + mask & htonl(~0 << (32 - mbits));
> +
> + ofs.start = TP_PORTS_OFS32;
> + goto range_out;
> + }
> out:
> /* Must unwildcard all the fields, as they were looked at. */
> flow_wildcards_fold_minimask(wc, &subtable->mask);
> @@ -1513,14 +1576,18 @@ minimatch_get_prefix(const struct minimatch *match, const struct mf_field *mf)
> static void
> trie_insert(struct cls_trie *trie, const struct cls_rule *rule, int mlen)
> {
> - const ovs_be32 *prefix = minimatch_get_prefix(&rule->match, trie->field);
> + trie_insert_prefix(&trie->root,
> + minimatch_get_prefix(&rule->match, trie->field), mlen);
> +}
> +
> +static void
> +trie_insert_prefix(struct trie_node **edge, const ovs_be32 *prefix, int mlen)
> +{
> struct trie_node *node;
> - struct trie_node **edge;
> int ofs = 0;
>
> /* Walk the tree. */
> - for (edge = &trie->root;
> - (node = *edge) != NULL;
> + for (; (node = *edge) != NULL;
> edge = trie_next_edge(node, prefix, ofs)) {
> unsigned int eqbits = trie_prefix_equal_bits(node, prefix, ofs, mlen);
> ofs += eqbits;
> @@ -1561,16 +1628,25 @@ trie_insert(struct cls_trie *trie, const struct cls_rule *rule, int mlen)
> static void
> trie_remove(struct cls_trie *trie, const struct cls_rule *rule, int mlen)
> {
> - const ovs_be32 *prefix = minimatch_get_prefix(&rule->match, trie->field);
> + trie_remove_prefix(&trie->root,
> + minimatch_get_prefix(&rule->match, trie->field), mlen);
> +}
> +
> +/* 'mlen' must be the (non-zero) CIDR prefix length of the 'trie->field' mask
> + * in 'rule'. */
> +static void
> +trie_remove_prefix(struct trie_node **root, const ovs_be32 *prefix, int mlen)
> +{
> struct trie_node *node;
> struct trie_node **edges[sizeof(union mf_value) * 8];
> int depth = 0, ofs = 0;
>
> /* Walk the tree. */
> - for (edges[depth] = &trie->root;
> + for (edges[0] = root;
> (node = *edges[depth]) != NULL;
> edges[++depth] = trie_next_edge(node, prefix, ofs)) {
> unsigned int eqbits = trie_prefix_equal_bits(node, prefix, ofs, mlen);
> +
> if (eqbits < node->nbits) {
> /* Mismatch, nothing to be removed. This should never happen, as
> * only rules in the classifier are ever removed. */
> diff --git a/lib/classifier.h b/lib/classifier.h
> index c3c1c3b..a1f4e4a 100644
> --- a/lib/classifier.h
> +++ b/lib/classifier.h
> @@ -276,6 +276,8 @@ struct cls_subtable {
> uint8_t index_ofs[CLS_MAX_INDICES]; /* u32 flow segment boundaries. */
> struct hindex indices[CLS_MAX_INDICES]; /* Staged lookup indices. */
> unsigned int trie_plen[CLS_MAX_TRIES]; /* Trie prefix length in 'mask'. */
> + struct trie_node *ports_trie; /* NULL if none. */
> + int ports_mask_len;
> };
>
> /* Returns true if 'table' is a "catch-all" subtable that will match every
> diff --git a/tests/classifier.at b/tests/classifier.at
> index b6c9352..5338a11 100644
> --- a/tests/classifier.at
> +++ b/tests/classifier.at
> @@ -55,7 +55,7 @@ Datapath actions: drop
> ])
> AT_CHECK([ovs-appctl ofproto/trace br0 'in_port=1,dl_src=50:54:00:00:00:05,dl_dst=50:54:00:00:00:07,dl_type=0x0800,nw_src=192.168.0.1,nw_dst=10.1.2.15,nw_proto=6,nw_tos=0,nw_ttl=128,tp_src=8,tp_dst=79'], [0], [stdout])
> AT_CHECK([tail -2 stdout], [0],
> - [Megaflow: recirc_id=0,skb_priority=0,tcp,in_port=1,nw_dst=10.1.2.15,nw_frag=no,tp_dst=79
> + [Megaflow: recirc_id=0,skb_priority=0,tcp,in_port=1,nw_dst=10.1.2.15,nw_frag=no,tp_dst=0x40/0xfff0
> Datapath actions: 2
> ])
> OVS_VSWITCHD_STOP
> @@ -78,6 +78,8 @@ AT_DATA([flows.txt], [dnl
> table=0 in_port=1 priority=16,tcp,nw_dst=10.1.0.0/255.255.0.0,action=output(3)
> table=0 in_port=1 priority=32,tcp,nw_dst=10.1.2.0/255.255.255.0,tp_src=79,action=output(2)
> table=0 in_port=1 priority=33,tcp,nw_dst=10.1.2.15,tp_dst=80,action=drop
> +table=0 in_port=1 priority=33,tcp,nw_dst=10.1.2.15,tp_dst=8080,action=output(2)
> +table=0 in_port=1 priority=33,tcp,nw_dst=10.1.2.15,tp_dst=192,action=output(2)
> table=0 in_port=1 priority=0,ip,action=drop
> table=0 in_port=2 priority=16,tcp,nw_dst=192.168.0.0/255.255.0.0,action=output(1)
> table=0 in_port=2 priority=0,ip,action=drop
> @@ -102,7 +104,7 @@ Datapath actions: drop
> ])
> AT_CHECK([ovs-appctl ofproto/trace br0 'in_port=1,dl_src=50:54:00:00:00:05,dl_dst=50:54:00:00:00:07,dl_type=0x0800,nw_src=192.168.0.1,nw_dst=10.1.2.15,nw_proto=6,nw_tos=0,nw_ttl=128,tp_src=8,tp_dst=79'], [0], [stdout])
> AT_CHECK([tail -2 stdout], [0],
> - [Megaflow: recirc_id=0,skb_priority=0,tcp,in_port=1,nw_dst=10.1.2.15,nw_frag=no,tp_src=8,tp_dst=79
> + [Megaflow: recirc_id=0,skb_priority=0,tcp,in_port=1,nw_dst=10.1.2.15,nw_frag=no,tp_src=0x0/0xffc0,tp_dst=0x40/0xfff0
> Datapath actions: 3
> ])
> OVS_VSWITCHD_STOP(["/'prefixes' with incompatible field: ipv6_label/d"])
> --
> 1.7.10.4
>
> _______________________________________________
> dev mailing list
> dev at openvswitch.org
> http://openvswitch.org/mailman/listinfo/dev
More information about the dev
mailing list