[dpdk-dev,2/2] event/sw: simplify credit scheme
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Commit Message
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>
---
drivers/event/sw/sw_evdev_worker.c | 38 +++++++++++++++++++-------------------
1 file changed, 19 insertions(+), 19 deletions(-)
Comments
> -----Original Message-----
> From: Eads, Gage
> Sent: Thursday, November 30, 2017 4:21 AM
> To: dev@dpdk.org
> Cc: jerin.jacob@caviumnetworks.com; Van Haaren, Harry
> <harry.van.haaren@intel.com>; Richardson, Bruce
> <bruce.richardson@intel.com>; hemant.agrawal@nxp.com; nipun.gupta@nxp.com;
> santosh.shukla@caviumnetworks.com
> Subject: [PATCH 2/2] event/sw: simplify credit scheme
>
> 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>
-----Original Message-----
> Date: Mon, 11 Dec 2017 13:42:08 +0000
> From: "Van Haaren, Harry" <harry.van.haaren@intel.com>
> To: "Eads, Gage" <gage.eads@intel.com>, "dev@dpdk.org" <dev@dpdk.org>
> CC: "jerin.jacob@caviumnetworks.com" <jerin.jacob@caviumnetworks.com>,
> "Richardson, Bruce" <bruce.richardson@intel.com>, "hemant.agrawal@nxp.com"
> <hemant.agrawal@nxp.com>, "nipun.gupta@nxp.com" <nipun.gupta@nxp.com>,
> "santosh.shukla@caviumnetworks.com" <santosh.shukla@caviumnetworks.com>
> Subject: RE: [PATCH 2/2] event/sw: simplify credit scheme
>
> > -----Original Message-----
> > From: Eads, Gage
> > Sent: Thursday, November 30, 2017 4:21 AM
> > To: dev@dpdk.org
> > Cc: jerin.jacob@caviumnetworks.com; Van Haaren, Harry
> > <harry.van.haaren@intel.com>; Richardson, Bruce
> > <bruce.richardson@intel.com>; hemant.agrawal@nxp.com; nipun.gupta@nxp.com;
> > santosh.shukla@caviumnetworks.com
> > Subject: [PATCH 2/2] event/sw: simplify credit scheme
> >
> > 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>
Applied this series to dpdk-next-eventdev/master. Thanks.
@@ -85,6 +85,7 @@ 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)
@@ -98,7 +99,6 @@ 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;
@@ -109,7 +109,6 @@ 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;
@@ -126,21 +125,16 @@ 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);
@@ -153,6 +147,13 @@ 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;
}
@@ -168,16 +169,22 @@ 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 */
@@ -188,8 +195,6 @@ 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();
@@ -197,11 +202,6 @@ 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;
}