1 /* SPDX-License-Identifier: BSD-3-Clause
2 * Copyright(c) 2016-2017 Intel Corporation
3 */
4
5 #include <rte_atomic.h>
6 #include <rte_cycles.h>
7 #include <rte_event_ring.h>
8
9 #include "sw_evdev.h"
10
11 #define PORT_ENQUEUE_MAX_BURST_SIZE 64
12
13 static inline void
sw_event_release(struct sw_port * p,uint8_t index)14 sw_event_release(struct sw_port *p, uint8_t index)
15 {
16 /*
17 * Drops the next outstanding event in our history. Used on dequeue
18 * to clear any history before dequeuing more events.
19 */
20 RTE_SET_USED(index);
21
22 /* create drop message */
23 struct rte_event ev;
24 ev.op = sw_qe_flag_map[RTE_EVENT_OP_RELEASE];
25
26 uint16_t free_count;
27 rte_event_ring_enqueue_burst(p->rx_worker_ring, &ev, 1, &free_count);
28
29 /* each release returns one credit */
30 p->outstanding_releases--;
31 p->inflight_credits++;
32 }
33
34 /*
35 * special-case of rte_event_ring enqueue, with overriding the ops member on
36 * the events that get written to the ring.
37 */
38 static inline unsigned int
enqueue_burst_with_ops(struct rte_event_ring * r,const struct rte_event * events,unsigned int n,uint8_t * ops)39 enqueue_burst_with_ops(struct rte_event_ring *r, const struct rte_event *events,
40 unsigned int n, uint8_t *ops)
41 {
42 struct rte_event tmp_evs[PORT_ENQUEUE_MAX_BURST_SIZE];
43 unsigned int i;
44
45 memcpy(tmp_evs, events, n * sizeof(events[0]));
46 for (i = 0; i < n; i++)
47 tmp_evs[i].op = ops[i];
48
49 return rte_event_ring_enqueue_burst(r, tmp_evs, n, NULL);
50 }
51
52 uint16_t
sw_event_enqueue_burst(void * port,const struct rte_event ev[],uint16_t num)53 sw_event_enqueue_burst(void *port, const struct rte_event ev[], uint16_t num)
54 {
55 int32_t i;
56 uint8_t new_ops[PORT_ENQUEUE_MAX_BURST_SIZE];
57 struct sw_port *p = port;
58 struct sw_evdev *sw = (void *)p->sw;
59 uint32_t sw_inflights = rte_atomic32_read(&sw->inflights);
60 uint32_t credit_update_quanta = sw->credit_update_quanta;
61 int new = 0;
62
63 if (num > PORT_ENQUEUE_MAX_BURST_SIZE)
64 num = PORT_ENQUEUE_MAX_BURST_SIZE;
65
66 for (i = 0; i < num; i++)
67 new += (ev[i].op == RTE_EVENT_OP_NEW);
68
69 if (unlikely(new > 0 && p->inflight_max < sw_inflights))
70 return 0;
71
72 if (p->inflight_credits < new) {
73 /* check if event enqueue brings port over max threshold */
74 if (sw_inflights + credit_update_quanta > sw->nb_events_limit)
75 return 0;
76
77 rte_atomic32_add(&sw->inflights, credit_update_quanta);
78 p->inflight_credits += (credit_update_quanta);
79
80 /* If there are fewer inflight credits than new events, limit
81 * the number of enqueued events.
82 */
83 num = (p->inflight_credits < new) ? p->inflight_credits : new;
84 }
85
86 for (i = 0; i < num; i++) {
87 int op = ev[i].op;
88 int outstanding = p->outstanding_releases > 0;
89 const uint8_t invalid_qid = (ev[i].queue_id >= sw->qid_count);
90
91 p->inflight_credits -= (op == RTE_EVENT_OP_NEW);
92 p->inflight_credits += (op == RTE_EVENT_OP_RELEASE) *
93 outstanding;
94
95 new_ops[i] = sw_qe_flag_map[op];
96 new_ops[i] &= ~(invalid_qid << QE_FLAG_VALID_SHIFT);
97
98 /* FWD and RELEASE packets will both resolve to taken (assuming
99 * correct usage of the API), providing very high correct
100 * prediction rate.
101 */
102 if ((new_ops[i] & QE_FLAG_COMPLETE) && outstanding)
103 p->outstanding_releases--;
104
105 /* error case: branch to avoid touching p->stats */
106 if (unlikely(invalid_qid && op != RTE_EVENT_OP_RELEASE)) {
107 p->stats.rx_dropped++;
108 p->inflight_credits++;
109 }
110 }
111
112 /* returns number of events actually enqueued */
113 uint32_t enq = enqueue_burst_with_ops(p->rx_worker_ring, ev, i,
114 new_ops);
115 if (p->outstanding_releases == 0 && p->last_dequeue_burst_sz != 0) {
116 uint64_t burst_ticks = rte_get_timer_cycles() -
117 p->last_dequeue_ticks;
118 uint64_t burst_pkt_ticks =
119 burst_ticks / p->last_dequeue_burst_sz;
120 p->avg_pkt_ticks -= p->avg_pkt_ticks / NUM_SAMPLES;
121 p->avg_pkt_ticks += burst_pkt_ticks / NUM_SAMPLES;
122 p->last_dequeue_ticks = 0;
123 }
124
125 /* Replenish credits if enough releases are performed */
126 if (p->inflight_credits >= credit_update_quanta * 2) {
127 rte_atomic32_sub(&sw->inflights, credit_update_quanta);
128 p->inflight_credits -= credit_update_quanta;
129 }
130
131 return enq;
132 }
133
134 uint16_t
sw_event_enqueue(void * port,const struct rte_event * ev)135 sw_event_enqueue(void *port, const struct rte_event *ev)
136 {
137 return sw_event_enqueue_burst(port, ev, 1);
138 }
139
140 uint16_t
sw_event_dequeue_burst(void * port,struct rte_event * ev,uint16_t num,uint64_t wait)141 sw_event_dequeue_burst(void *port, struct rte_event *ev, uint16_t num,
142 uint64_t wait)
143 {
144 RTE_SET_USED(wait);
145 struct sw_port *p = (void *)port;
146 struct rte_event_ring *ring = p->cq_worker_ring;
147
148 /* check that all previous dequeues have been released */
149 if (p->implicit_release) {
150 struct sw_evdev *sw = (void *)p->sw;
151 uint32_t credit_update_quanta = sw->credit_update_quanta;
152 uint16_t out_rels = p->outstanding_releases;
153 uint16_t i;
154 for (i = 0; i < out_rels; i++)
155 sw_event_release(p, i);
156
157 /* Replenish credits if enough releases are performed */
158 if (p->inflight_credits >= credit_update_quanta * 2) {
159 rte_atomic32_sub(&sw->inflights, credit_update_quanta);
160 p->inflight_credits -= credit_update_quanta;
161 }
162 }
163
164 /* returns number of events actually dequeued */
165 uint16_t ndeq = rte_event_ring_dequeue_burst(ring, ev, num, NULL);
166 if (unlikely(ndeq == 0)) {
167 p->zero_polls++;
168 p->total_polls++;
169 goto end;
170 }
171
172 p->outstanding_releases += ndeq;
173 p->last_dequeue_burst_sz = ndeq;
174 p->last_dequeue_ticks = rte_get_timer_cycles();
175 p->poll_buckets[(ndeq - 1) >> SW_DEQ_STAT_BUCKET_SHIFT]++;
176 p->total_polls++;
177
178 end:
179 return ndeq;
180 }
181
182 uint16_t
sw_event_dequeue(void * port,struct rte_event * ev,uint64_t wait)183 sw_event_dequeue(void *port, struct rte_event *ev, uint64_t wait)
184 {
185 return sw_event_dequeue_burst(port, ev, 1, wait);
186 }
187