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event/sw: simplify credit scheme

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This commit modifies the sw PMD credit scheme such that credits are
consumed when enqueueing a NEW event and released when an event is
released -- typically, the beginning and end of a pipeline. Workers that
simply forward events do not interact with the credit pool.

Signed-off-by: Gage Eads <gage.eads@intel.com>
Acked-by: Harry van Haaren <harry.van.haaren@intel.com>
This commit is contained in:
Gage Eads 2017-12-11 11:56:32 -06:00 committed by Jerin Jacob
parent ec36d881f5
commit decdc1cdca
1 changed files with 19 additions and 19 deletions
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38
drivers/event/sw/sw_evdev_worker.c
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@ -57,6 +57,7 @@ sw_event_enqueue_burst(void *port, const struct rte_event ev[], uint16_t num)
struct sw_port *p = port;
struct sw_evdev *sw = (void *)p->sw;
uint32_t sw_inflights = rte_atomic32_read(&sw->inflights);
uint32_t credit_update_quanta = sw->credit_update_quanta;
int new = 0;
if (num > PORT_ENQUEUE_MAX_BURST_SIZE)
@ -70,7 +71,6 @@ sw_event_enqueue_burst(void *port, const struct rte_event ev[], uint16_t num)
if (p->inflight_credits < new) {
/* check if event enqueue brings port over max threshold */
uint32_t credit_update_quanta = sw->credit_update_quanta;
if (sw_inflights + credit_update_quanta > sw->nb_events_limit)
return 0;
@ -81,7 +81,6 @@ sw_event_enqueue_burst(void *port, const struct rte_event ev[], uint16_t num)
return 0;
}
uint32_t completions = 0;
for (i = 0; i < num; i++) {
int op = ev[i].op;
int outstanding = p->outstanding_releases > 0;
@ -98,21 +97,16 @@ sw_event_enqueue_burst(void *port, const struct rte_event ev[], uint16_t num)
* correct usage of the API), providing very high correct
* prediction rate.
*/
if ((new_ops[i] & QE_FLAG_COMPLETE) && outstanding) {
if ((new_ops[i] & QE_FLAG_COMPLETE) && outstanding)
p->outstanding_releases--;
completions++;
}
/* error case: branch to avoid touching p->stats */
if (unlikely(invalid_qid)) {
if (unlikely(invalid_qid && op != RTE_EVENT_OP_RELEASE)) {
p->stats.rx_dropped++;
p->inflight_credits++;
}
}
/* handle directed port forward and release credits */
p->inflight_credits -= completions * p->is_directed;
/* returns number of events actually enqueued */
uint32_t enq = enqueue_burst_with_ops(p->rx_worker_ring, ev, i,
new_ops);
@ -125,6 +119,13 @@ sw_event_enqueue_burst(void *port, const struct rte_event ev[], uint16_t num)
p->avg_pkt_ticks += burst_pkt_ticks / NUM_SAMPLES;
p->last_dequeue_ticks = 0;
}
/* Replenish credits if enough releases are performed */
if (p->inflight_credits >= credit_update_quanta * 2) {
rte_atomic32_sub(&sw->inflights, credit_update_quanta);
p->inflight_credits -= credit_update_quanta;
}
return enq;
}
@ -140,16 +141,22 @@ sw_event_dequeue_burst(void *port, struct rte_event *ev, uint16_t num,
{
RTE_SET_USED(wait);
struct sw_port *p = (void *)port;
struct sw_evdev *sw = (void *)p->sw;
struct rte_event_ring *ring = p->cq_worker_ring;
uint32_t credit_update_quanta = sw->credit_update_quanta;
/* check that all previous dequeues have been released */
if (p->implicit_release && !p->is_directed) {
if (p->implicit_release) {
struct sw_evdev *sw = (void *)p->sw;
uint32_t credit_update_quanta = sw->credit_update_quanta;
uint16_t out_rels = p->outstanding_releases;
uint16_t i;
for (i = 0; i < out_rels; i++)
sw_event_release(p, i);
/* Replenish credits if enough releases are performed */
if (p->inflight_credits >= credit_update_quanta * 2) {
rte_atomic32_sub(&sw->inflights, credit_update_quanta);
p->inflight_credits -= credit_update_quanta;
}
}
/* returns number of events actually dequeued */
@ -160,8 +167,6 @@ sw_event_dequeue_burst(void *port, struct rte_event *ev, uint16_t num,
goto end;
}
/* only add credits for directed ports - LB ports send RELEASEs */
p->inflight_credits += ndeq * p->is_directed;
p->outstanding_releases += ndeq;
p->last_dequeue_burst_sz = ndeq;
p->last_dequeue_ticks = rte_get_timer_cycles();
@ -169,11 +174,6 @@ sw_event_dequeue_burst(void *port, struct rte_event *ev, uint16_t num,
p->total_polls++;
end:
if (p->inflight_credits >= credit_update_quanta * 2 &&
p->inflight_credits > credit_update_quanta + ndeq) {
rte_atomic32_sub(&sw->inflights, credit_update_quanta);
p->inflight_credits -= credit_update_quanta;
}
return ndeq;
}