[dpdk-dev] [PATCH v11 5/5] net/ice: use WC store to update queue tail registers

[Radu Nicolau]

Performance improvement: use a write combining store
instead of a regular mmio write to update queue tail
registers.

Signed-off-by: Radu Nicolau <radu.nicolau at intel.com>
---
 drivers/net/ice/base/ice_osdep.h    | 1 +
 drivers/net/ice/ice_rxtx.c          | 6 +++---
 drivers/net/ice/ice_rxtx_vec_avx2.c | 4 ++--
 drivers/net/ice/ice_rxtx_vec_sse.c  | 4 ++--
 4 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/drivers/net/ice/base/ice_osdep.h b/drivers/net/ice/base/ice_osdep.h
index 360e435b8..c793f1e38 100644
--- a/drivers/net/ice/base/ice_osdep.h
+++ b/drivers/net/ice/base/ice_osdep.h
@@ -165,6 +165,7 @@ do {									\
 #endif
 
 #define ICE_PCI_REG_WRITE(reg, value) writel(value, reg)
+#define ICE_PCI_REG_WC_WRITE(reg, value) rte_write32_wc(value, reg)
 
 #define ICE_READ_REG(hw, reg)         rd32(hw, reg)
 #define ICE_WRITE_REG(hw, reg, value) wr32(hw, reg, value)
diff --git a/drivers/net/ice/ice_rxtx.c b/drivers/net/ice/ice_rxtx.c
index 2e1f06d2c..d23841623 100644
--- a/drivers/net/ice/ice_rxtx.c
+++ b/drivers/net/ice/ice_rxtx.c
@@ -1741,7 +1741,7 @@ ice_recv_scattered_pkts(void *rx_queue,
 		rx_id = (uint16_t)(rx_id == 0 ?
 				   (rxq->nb_rx_desc - 1) : (rx_id - 1));
 		/* write TAIL register */
-		ICE_PCI_REG_WRITE(rxq->qrx_tail, rx_id);
+		ICE_PCI_REG_WC_WRITE(rxq->qrx_tail, rx_id);
 		nb_hold = 0;
 	}
 	rxq->nb_rx_hold = nb_hold;
@@ -2131,7 +2131,7 @@ ice_recv_pkts(void *rx_queue,
 		rx_id = (uint16_t)(rx_id == 0 ?
 				   (rxq->nb_rx_desc - 1) : (rx_id - 1));
 		/* write TAIL register */
-		ICE_PCI_REG_WRITE(rxq->qrx_tail, rx_id);
+		ICE_PCI_REG_WC_WRITE(rxq->qrx_tail, rx_id);
 		nb_hold = 0;
 	}
 	rxq->nb_rx_hold = nb_hold;
@@ -2846,7 +2846,7 @@ tx_xmit_pkts(struct ice_tx_queue *txq,
 		txq->tx_tail = 0;
 
 	/* Update the tx tail register */
-	ICE_PCI_REG_WRITE(txq->qtx_tail, txq->tx_tail);
+	ICE_PCI_REG_WC_WRITE(txq->qtx_tail, txq->tx_tail);
 
 	return nb_pkts;
 }
diff --git a/drivers/net/ice/ice_rxtx_vec_avx2.c b/drivers/net/ice/ice_rxtx_vec_avx2.c
index be50677c2..d9d475863 100644
--- a/drivers/net/ice/ice_rxtx_vec_avx2.c
+++ b/drivers/net/ice/ice_rxtx_vec_avx2.c
@@ -129,7 +129,7 @@ ice_rxq_rearm(struct ice_rx_queue *rxq)
 			     (rxq->nb_rx_desc - 1) : (rxq->rxrearm_start - 1));
 
 	/* Update the tail pointer on the NIC */
-	ICE_PCI_REG_WRITE(rxq->qrx_tail, rx_id);
+	ICE_PCI_REG_WC_WRITE(rxq->qrx_tail, rx_id);
 }
 
 static inline uint16_t
@@ -810,7 +810,7 @@ ice_xmit_fixed_burst_vec_avx2(void *tx_queue, struct rte_mbuf **tx_pkts,
 
 	txq->tx_tail = tx_id;
 
-	ICE_PCI_REG_WRITE(txq->qtx_tail, txq->tx_tail);
+	ICE_PCI_REG_WC_WRITE(txq->qtx_tail, txq->tx_tail);
 
 	return nb_pkts;
 }
diff --git a/drivers/net/ice/ice_rxtx_vec_sse.c b/drivers/net/ice/ice_rxtx_vec_sse.c
index 382ef31f3..3de162af0 100644
--- a/drivers/net/ice/ice_rxtx_vec_sse.c
+++ b/drivers/net/ice/ice_rxtx_vec_sse.c
@@ -78,7 +78,7 @@ ice_rxq_rearm(struct ice_rx_queue *rxq)
 			   (rxq->nb_rx_desc - 1) : (rxq->rxrearm_start - 1));
 
 	/* Update the tail pointer on the NIC */
-	ICE_PCI_REG_WRITE(rxq->qrx_tail, rx_id);
+	ICE_PCI_REG_WC_WRITE(rxq->qrx_tail, rx_id);
 }
 
 static inline void
@@ -583,7 +583,7 @@ ice_xmit_fixed_burst_vec(void *tx_queue, struct rte_mbuf **tx_pkts,
 
 	txq->tx_tail = tx_id;
 
-	ICE_PCI_REG_WRITE(txq->qtx_tail, txq->tx_tail);
+	ICE_PCI_REG_WC_WRITE(txq->qtx_tail, txq->tx_tail);
 
 	return nb_pkts;
 }
-- 
2.17.1