[dpdk-dev,2/2] event/sw: simplify credit scheme

Message ID 1512015636-31878-3-git-send-email-gage.eads@intel.com
State Superseded, archived
Delegated to: Jerin Jacob
Headers show

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Context Check Description
ci/Intel-compilation success Compilation OK
ci/checkpatch success coding style OK

Commit Message

Eads, Gage Nov. 30, 2017, 4:20 a.m.
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

Van Haaren, Harry Dec. 11, 2017, 1:42 p.m. | #1
> -----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>
Jerin Jacob Dec. 16, 2017, 8:54 a.m. | #2
-----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.

Patch

diff --git a/drivers/event/sw/sw_evdev_worker.c b/drivers/event/sw/sw_evdev_worker.c
index 93cd29b..766c836 100644
--- a/drivers/event/sw/sw_evdev_worker.c
+++ b/drivers/event/sw/sw_evdev_worker.c
@@ -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;
 }