[dpdk-dev] [PATCH v2 8/8] net/mlx4: remove Tx completion elements counter

[Matan Azrad <matan@mellanox.com>]

This counter saved the descriptor elements which are waiting to be
completted and was used to know if completion function should be
called.

This completion check can be done by other elements management
variables and we can prevent this counter management.

Remove this counter and replace the completion check easily by other
elements management variables.

Signed-off-by: Matan Azrad <matan@mellanox.com>
Acked-by: Adrien Mazarguil <adrien.mazarguil@6wind.com>
---
 drivers/net/mlx4/mlx4_rxtx.c | 8 +++-----
 drivers/net/mlx4/mlx4_rxtx.h | 1 -
 drivers/net/mlx4/mlx4_txq.c  | 1 -
 3 files changed, 3 insertions(+), 7 deletions(-)

diff --git a/drivers/net/mlx4/mlx4_rxtx.c b/drivers/net/mlx4/mlx4_rxtx.c
index 14192fe..1b598f2 100644
--- a/drivers/net/mlx4/mlx4_rxtx.c
+++ b/drivers/net/mlx4/mlx4_rxtx.c
@@ -367,7 +367,6 @@ struct pv {
 	/* Update CQ consumer index. */
 	cq->cons_index = cons_index;
 	*cq->set_ci_db = rte_cpu_to_be_32(cons_index & MLX4_CQ_DB_CI_MASK);
-	txq->elts_comp -= completed;
 	txq->elts_tail = elts_tail;
 }
 
@@ -585,15 +584,15 @@ struct pv {
 	const unsigned int elts_m = elts_n - 1;
 	unsigned int bytes_sent = 0;
 	unsigned int i;
-	unsigned int max;
+	unsigned int max = elts_head - txq->elts_tail;
 	struct mlx4_sq *sq = &txq->msq;
 	volatile struct mlx4_wqe_ctrl_seg *ctrl;
 	struct txq_elt *elt;
 
 	assert(txq->elts_comp_cd != 0);
-	if (likely(txq->elts_comp != 0))
+	if (likely(max >= txq->elts_comp_cd_init))
 		mlx4_txq_complete(txq, elts_m, sq);
-	max = (elts_n - (elts_head - txq->elts_tail));
+	max = elts_n - max;
 	assert(max >= 1);
 	assert(max <= elts_n);
 	/* Always leave one free entry in the ring. */
@@ -740,7 +739,6 @@ struct pv {
 	/* Ring QP doorbell. */
 	rte_write32(txq->msq.doorbell_qpn, txq->msq.db);
 	txq->elts_head += i;
-	txq->elts_comp += i;
 	return i;
 }
 
diff --git a/drivers/net/mlx4/mlx4_rxtx.h b/drivers/net/mlx4/mlx4_rxtx.h
index 36ae03a..b93e2bc 100644
--- a/drivers/net/mlx4/mlx4_rxtx.h
+++ b/drivers/net/mlx4/mlx4_rxtx.h
@@ -125,7 +125,6 @@ struct txq {
 	struct mlx4_cq mcq; /**< Info for directly manipulating the CQ. */
 	unsigned int elts_head; /**< Current index in (*elts)[]. */
 	unsigned int elts_tail; /**< First element awaiting completion. */
-	unsigned int elts_comp; /**< Number of packets awaiting completion. */
 	int elts_comp_cd; /**< Countdown for next completion. */
 	unsigned int elts_comp_cd_init; /**< Initial value for countdown. */
 	unsigned int elts_n; /**< (*elts)[] length. */
diff --git a/drivers/net/mlx4/mlx4_txq.c b/drivers/net/mlx4/mlx4_txq.c
index 7eb4b04..0c35935 100644
--- a/drivers/net/mlx4/mlx4_txq.c
+++ b/drivers/net/mlx4/mlx4_txq.c
@@ -274,7 +274,6 @@ struct txq_mp2mr_mbuf_check_data {
 		.elts = elts,
 		.elts_head = 0,
 		.elts_tail = 0,
-		.elts_comp = 0,
 		/*
 		 * Request send completion every MLX4_PMD_TX_PER_COMP_REQ
 		 * packets or at least 4 times per ring.
-- 
1.8.3.1