[ovs-dev] [PATCH v2] lib/classifier: Use a prefix tree to optimize ports wildcarding.
Jarno Rajahalme
jrajahalme at nicira.com
Wed Apr 16 21:40:54 UTC 2014
Thanks for your review! I'll hold on to this until we have figured out when to enable this feature.
Jarno
> On Apr 16, 2014, at 2:28 PM, Ethan Jackson <ethan at nicira.com> wrote:
>
> 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
>>
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