Re: [dpdk-dev] [PATCH] event/sw: fix credit tracking in port dequeue

["Eads, Gage" <gage.eads@intel.com>]

A couple nit-picks on the test, but once resolved:
Acked-by: Gage Eads <gage.eads@intel.com>

>  -----Original Message-----
>  From: Van Haaren, Harry
>  Sent: Monday, May 29, 2017 10:17 AM
>  To: dev@dpdk.org
>  Cc: jerin.jacob@caviumnetworks.com; Eads, Gage <gage.eads@intel.com>;
>  Van Haaren, Harry <harry.van.haaren@intel.com>
>  Subject: [PATCH] event/sw: fix credit tracking in port dequeue
>  
>  This patch targets the next-eventdev tree.
>  
>  Single-link optimized ports previously did not correctly track credits when
>  dequeued, and re-enqueued as a FORWARD type. This could "inflate" the
>  number of credits in the system.
>  
>  A unit test is added to reproduce and verify the issue. The fixed implementation
>  counts FORWARD packets and reduces the number of credits the port has if it is
>  of single-link type.
>  
>  Fixes: 656af9180014 ("event/sw: add worker core functions")
>  
>  Signed-off-by: Harry van Haaren <harry.van.haaren@intel.com>
>  ---
>   drivers/event/sw/sw_evdev_worker.c |  5 ++++
>   test/test/test_eventdev_sw.c       | 58
>  +++++++++++++++++++++++++++++++++++++-
>   2 files changed, 62 insertions(+), 1 deletion(-)
>  
>  diff --git a/drivers/event/sw/sw_evdev_worker.c
>  b/drivers/event/sw/sw_evdev_worker.c
>  index 9cb6bef..b738506 100644
>  --- a/drivers/event/sw/sw_evdev_worker.c
>  +++ b/drivers/event/sw/sw_evdev_worker.c
>  @@ -87,6 +87,7 @@ sw_event_enqueue_burst(void *port, const struct
>  rte_event ev[], uint16_t num)
>   			return 0;
>   	}
>  
>  +	uint32_t forwards = 0;
>   	for (i = 0; i < num; i++) {
>   		int op = ev[i].op;
>   		int outstanding = p->outstanding_releases > 0; @@ -95,6
>  +96,7 @@ sw_event_enqueue_burst(void *port, const struct rte_event ev[],
>  uint16_t num)
>   		p->inflight_credits -= (op == RTE_EVENT_OP_NEW);
>   		p->inflight_credits += (op == RTE_EVENT_OP_RELEASE) *
>   					outstanding;
>  +		forwards += (op == RTE_EVENT_OP_FORWARD);
>  
>   		new_ops[i] = sw_qe_flag_map[op];
>   		new_ops[i] &= ~(invalid_qid << QE_FLAG_VALID_SHIFT); @@ -
>  113,6 +115,9 @@ sw_event_enqueue_burst(void *port, const struct rte_event
>  ev[], uint16_t num)
>   		}
>   	}
>  
>  +	/* handle directed port forward credits */
>  +	p->inflight_credits -= forwards * p->is_directed;
>  +
>   	/* returns number of events actually enqueued */
>   	uint32_t enq = qe_ring_enqueue_burst_with_ops(p->rx_worker_ring,
>  ev, i,
>   					     new_ops);
>  diff --git a/test/test/test_eventdev_sw.c b/test/test/test_eventdev_sw.c index
>  b187d02..aaa9729 100644
>  --- a/test/test/test_eventdev_sw.c
>  +++ b/test/test/test_eventdev_sw.c
>  @@ -548,6 +548,57 @@ test_single_directed_packet(struct test *t)
>   	return 0;
>   }
>  
>  +static int
>  +test_directed_forward_credits(struct test *t) {
>  +	uint32_t i;
>  +	int32_t err;
>  +
>  +	if (init(t, 1, 1) < 0 ||
>  +			create_ports(t, 1) < 0 ||
>  +			create_directed_qids(t, 1, t->port) < 0)
>  +		return -1;
>  +
>  +	if (rte_event_dev_start(evdev) < 0) {
>  +		printf("%d: Error with start call\n", __LINE__);
>  +		return -1;
>  +	}
>  +
>  +	struct rte_event ev = {
>  +			.op = RTE_EVENT_OP_NEW,
>  +			.queue_id = 0,
>  +	};
>  +
>  +	for (i = 0; i < 1000; i++) {
>  +		err = rte_event_enqueue_burst(evdev, 0, &ev, 1);
>  +		if (err < 0) {
>  +			printf("%d: error failed to enqueue\n", __LINE__);
>  +			return -1;
>  +		}
>  +		rte_event_schedule(evdev);
>  +		struct test_event_dev_stats stats;
>  +		err = test_event_dev_stats_get(evdev, &stats);

Does this stats get call serve a purpose?

>  +		if (err) {
>  +			printf("%d: error failed to get stats\n", __LINE__);
>  +			return -1;
>  +		}
>  +
>  +		uint32_t deq_pkts;
>  +		deq_pkts = rte_event_dequeue_burst(evdev, 0, &ev, 1, 0);
>  +		if (deq_pkts != 1) {
>  +			printf("%d: error failed to deq\n", __LINE__);
>  +			return -1;
>  +		}
>  +
>  +		/* re-write event to be a forward, and continue looping it */
>  +		ev.op = RTE_EVENT_OP_FORWARD;
>  +	}
>  +
>  +	//rte_event_dev_dump(0, stdout);

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