2 * Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2016 Nicira, Inc.
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at:
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
19 #include <sys/types.h>
20 #include <netinet/in.h>
21 #include <arpa/inet.h>
27 #include "openvswitch/ofpbuf.h"
28 #include "openflow/openflow.h"
29 #include "poll-loop.h"
34 #include "openvswitch/token-bucket.h"
35 #include "openvswitch/vconn.h"
38 struct hmap_node node
; /* In struct pinsched's 'queues' hmap. */
39 ofp_port_t port_no
; /* Port number. */
40 struct ovs_list packets
; /* Contains "struct ofpbuf"s. */
41 int n
; /* Number of packets in 'packets'. */
45 struct token_bucket token_bucket
;
47 /* One queue per physical port. */
48 struct hmap queues
; /* Contains "struct pinqueue"s. */
49 unsigned int n_queued
; /* Sum over queues[*].n. */
50 struct pinqueue
*next_txq
; /* Next pinqueue check in round-robin. */
52 /* Statistics reporting. */
53 unsigned long long n_normal
; /* # txed w/o rate limit queuing. */
54 unsigned long long n_limited
; /* # queued for rate limiting. */
55 unsigned long long n_queue_dropped
; /* # dropped due to queue overflow. */
59 advance_txq(struct pinsched
*ps
)
61 struct hmap_node
*next
;
64 ? hmap_next(&ps
->queues
, &ps
->next_txq
->node
)
65 : hmap_first(&ps
->queues
));
66 ps
->next_txq
= next
? CONTAINER_OF(next
, struct pinqueue
, node
) : NULL
;
69 static struct ofpbuf
*
70 dequeue_packet(struct pinsched
*ps
, struct pinqueue
*q
)
72 struct ofpbuf
*packet
= ofpbuf_from_list(ovs_list_pop_front(&q
->packets
));
79 adjust_limits(int *rate_limit
, int *burst_limit
)
81 if (*rate_limit
<= 0) {
84 if (*burst_limit
<= 0) {
85 *burst_limit
= *rate_limit
/ 4;
87 if (*burst_limit
< 1) {
92 /* Destroys 'q' and removes it from 'ps''s set of queues.
93 * (The caller must ensure that 'q' is empty.) */
95 pinqueue_destroy(struct pinsched
*ps
, struct pinqueue
*q
)
97 hmap_remove(&ps
->queues
, &q
->node
);
101 static struct pinqueue
*
102 pinqueue_get(struct pinsched
*ps
, ofp_port_t port_no
)
104 uint32_t hash
= hash_ofp_port(port_no
);
107 HMAP_FOR_EACH_IN_BUCKET (q
, node
, hash
, &ps
->queues
) {
108 if (port_no
== q
->port_no
) {
113 q
= xmalloc(sizeof *q
);
114 hmap_insert(&ps
->queues
, &q
->node
, hash
);
115 q
->port_no
= port_no
;
116 ovs_list_init(&q
->packets
);
121 /* Drop a packet from the longest queue in 'ps'. */
123 drop_packet(struct pinsched
*ps
)
125 struct pinqueue
*longest
; /* Queue currently selected as longest. */
126 int n_longest
= 0; /* # of queues of same length as 'longest'. */
129 ps
->n_queue_dropped
++;
132 HMAP_FOR_EACH (q
, node
, &ps
->queues
) {
133 if (!longest
|| longest
->n
< q
->n
) {
136 } else if (longest
->n
== q
->n
) {
139 /* Randomly select one of the longest queues, with a uniform
140 * distribution (Knuth algorithm 3.4.2R). */
141 if (!random_range(n_longest
)) {
147 /* FIXME: do we want to pop the tail instead? */
148 ofpbuf_delete(dequeue_packet(ps
, longest
));
149 if (longest
->n
== 0) {
150 pinqueue_destroy(ps
, longest
);
154 /* Remove and return the next packet to transmit (in round-robin order). */
155 static struct ofpbuf
*
156 get_tx_packet(struct pinsched
*ps
)
158 struct ofpbuf
*packet
;
166 packet
= dequeue_packet(ps
, q
);
169 pinqueue_destroy(ps
, q
);
175 /* Attempts to remove enough tokens from 'ps' to transmit a packet. Returns
176 * true if successful, false otherwise. (In the latter case no tokens are
179 get_token(struct pinsched
*ps
)
181 return token_bucket_withdraw(&ps
->token_bucket
, 1000);
185 pinsched_send(struct pinsched
*ps
, ofp_port_t port_no
,
186 struct ofpbuf
*packet
, struct ovs_list
*txq
)
190 ovs_list_push_back(txq
, &packet
->list_node
);
191 } else if (!ps
->n_queued
&& get_token(ps
)) {
192 /* In the common case where we are not constrained by the rate limit,
193 * let the packet take the normal path. */
195 ovs_list_push_back(txq
, &packet
->list_node
);
197 /* Otherwise queue it up for the periodic callback to drain out. */
198 if (ps
->n_queued
* 1000 >= ps
->token_bucket
.burst
) {
202 struct pinqueue
*q
= pinqueue_get(ps
, port_no
);
203 ovs_list_push_back(&q
->packets
, &packet
->list_node
);
211 pinsched_run(struct pinsched
*ps
, struct ovs_list
*txq
)
217 /* Drain some packets out of the bucket if possible, but limit the
218 * number of iterations to allow other code to get work done too. */
219 for (i
= 0; ps
->n_queued
&& get_token(ps
) && i
< 50; i
++) {
220 struct ofpbuf
*packet
= get_tx_packet(ps
);
221 ovs_list_push_back(txq
, &packet
->list_node
);
227 pinsched_wait(struct pinsched
*ps
)
229 if (ps
&& ps
->n_queued
) {
230 token_bucket_wait(&ps
->token_bucket
, 1000);
234 /* Creates and returns a scheduler for sending packet-in messages. */
236 pinsched_create(int rate_limit
, int burst_limit
)
240 ps
= xzalloc(sizeof *ps
);
242 adjust_limits(&rate_limit
, &burst_limit
);
243 token_bucket_init(&ps
->token_bucket
,
244 rate_limit
, sat_mul(burst_limit
, 1000));
246 hmap_init(&ps
->queues
);
251 ps
->n_queue_dropped
= 0;
257 pinsched_destroy(struct pinsched
*ps
)
262 HMAP_FOR_EACH_POP (q
, node
, &ps
->queues
) {
263 ofpbuf_list_delete(&q
->packets
);
266 hmap_destroy(&ps
->queues
);
272 pinsched_get_limits(const struct pinsched
*ps
,
273 int *rate_limit
, int *burst_limit
)
275 *rate_limit
= ps
->token_bucket
.rate
;
276 *burst_limit
= ps
->token_bucket
.burst
/ 1000;
280 pinsched_set_limits(struct pinsched
*ps
, int rate_limit
, int burst_limit
)
282 adjust_limits(&rate_limit
, &burst_limit
);
283 token_bucket_set(&ps
->token_bucket
,
284 rate_limit
, sat_mul(burst_limit
, 1000));
285 while (ps
->n_queued
> burst_limit
) {
290 /* Retrieves statistics for 'ps'. The statistics will be all zero if 'ps' is
293 pinsched_get_stats(const struct pinsched
*ps
, struct pinsched_stats
*stats
)
296 stats
->n_queued
= ps
->n_queued
;
297 stats
->n_normal
= ps
->n_normal
;
298 stats
->n_limited
= ps
->n_limited
;
299 stats
->n_queue_dropped
= ps
->n_queue_dropped
;
301 memset(stats
, 0, sizeof *stats
);