[dpdk-dev] [PATCH v7 2/4] net/i40e: use WC store to update queue tail registers

Radu Nicolau radu.nicolau at intel.com
Thu Jul 16 14:29:14 CEST 2020


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>
Acked-by: Bruce Richardson <bruce.richardson at intel.com>
---
 drivers/net/i40e/base/i40e_osdep.h    | 5 +++++
 drivers/net/i40e/i40e_rxtx.c          | 8 ++++----
 drivers/net/i40e/i40e_rxtx_vec_avx2.c | 4 ++--
 drivers/net/i40e/i40e_rxtx_vec_sse.c  | 4 ++--
 4 files changed, 13 insertions(+), 8 deletions(-)

diff --git a/drivers/net/i40e/base/i40e_osdep.h b/drivers/net/i40e/base/i40e_osdep.h
index 58be396..69ab717 100644
--- a/drivers/net/i40e/base/i40e_osdep.h
+++ b/drivers/net/i40e/base/i40e_osdep.h
@@ -138,6 +138,11 @@ static inline uint32_t i40e_read_addr(volatile void *addr)
 #define I40E_PCI_REG_WRITE_RELAXED(reg, value)	\
 	rte_write32_relaxed((rte_cpu_to_le_32(value)), reg)
 
+#define I40E_PCI_REG_WC_WRITE(queue, reg, value) \
+	rte_write32_wc((rte_cpu_to_le_32(value)), reg)
+#define I40E_PCI_REG_WC_WRITE_RELAXED(queue, reg, value) \
+	rte_write32_wc_relaxed((rte_cpu_to_le_32(value)), reg)
+
 #define I40E_WRITE_FLUSH(a) I40E_READ_REG(a, I40E_GLGEN_STAT)
 #define I40EVF_WRITE_FLUSH(a) I40E_READ_REG(a, I40E_VFGEN_RSTAT)
 
diff --git a/drivers/net/i40e/i40e_rxtx.c b/drivers/net/i40e/i40e_rxtx.c
index 840b6f3..64e43ac 100644
--- a/drivers/net/i40e/i40e_rxtx.c
+++ b/drivers/net/i40e/i40e_rxtx.c
@@ -760,7 +760,7 @@ i40e_recv_pkts(void *rx_queue, struct rte_mbuf **rx_pkts, uint16_t nb_pkts)
 	if (nb_hold > rxq->rx_free_thresh) {
 		rx_id = (uint16_t) ((rx_id == 0) ?
 			(rxq->nb_rx_desc - 1) : (rx_id - 1));
-		I40E_PCI_REG_WRITE(rxq->qrx_tail, rx_id);
+		I40E_PCI_REG_WC_WRITE(rxq, rxq->qrx_tail, rx_id);
 		nb_hold = 0;
 	}
 	rxq->nb_rx_hold = nb_hold;
@@ -938,7 +938,7 @@ i40e_recv_scattered_pkts(void *rx_queue,
 	if (nb_hold > rxq->rx_free_thresh) {
 		rx_id = (uint16_t)(rx_id == 0 ?
 			(rxq->nb_rx_desc - 1) : (rx_id - 1));
-		I40E_PCI_REG_WRITE(rxq->qrx_tail, rx_id);
+		I40E_PCI_REG_WC_WRITE(rxq, rxq->qrx_tail, rx_id);
 		nb_hold = 0;
 	}
 	rxq->nb_rx_hold = nb_hold;
@@ -1249,7 +1249,7 @@ i40e_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts, uint16_t nb_pkts)
 		   (unsigned) tx_id, (unsigned) nb_tx);
 
 	rte_cio_wmb();
-	I40E_PCI_REG_WRITE_RELAXED(txq->qtx_tail, tx_id);
+	I40E_PCI_REG_WC_WRITE_RELAXED(txq, txq->qtx_tail, tx_id);
 	txq->tx_tail = tx_id;
 
 	return nb_tx;
@@ -1400,7 +1400,7 @@ tx_xmit_pkts(struct i40e_tx_queue *txq,
 		txq->tx_tail = 0;
 
 	/* Update the tx tail register */
-	I40E_PCI_REG_WRITE(txq->qtx_tail, txq->tx_tail);
+	I40E_PCI_REG_WC_WRITE(txq, txq->qtx_tail, txq->tx_tail);
 
 	return nb_pkts;
 }
diff --git a/drivers/net/i40e/i40e_rxtx_vec_avx2.c b/drivers/net/i40e/i40e_rxtx_vec_avx2.c
index 3bcef13..294c1c4 100644
--- a/drivers/net/i40e/i40e_rxtx_vec_avx2.c
+++ b/drivers/net/i40e/i40e_rxtx_vec_avx2.c
@@ -134,7 +134,7 @@ i40e_rxq_rearm(struct i40e_rx_queue *rxq)
 			     (rxq->nb_rx_desc - 1) : (rxq->rxrearm_start - 1));
 
 	/* Update the tail pointer on the NIC */
-	I40E_PCI_REG_WRITE(rxq->qrx_tail, rx_id);
+	I40E_PCI_REG_WC_WRITE(rxq, rxq->qrx_tail, rx_id);
 }
 
 #ifndef RTE_LIBRTE_I40E_16BYTE_RX_DESC
@@ -921,7 +921,7 @@ i40e_xmit_fixed_burst_vec_avx2(void *tx_queue, struct rte_mbuf **tx_pkts,
 
 	txq->tx_tail = tx_id;
 
-	I40E_PCI_REG_WRITE(txq->qtx_tail, txq->tx_tail);
+	I40E_PCI_REG_WC_WRITE(txq, txq->qtx_tail, txq->tx_tail);
 
 	return nb_pkts;
 }
diff --git a/drivers/net/i40e/i40e_rxtx_vec_sse.c b/drivers/net/i40e/i40e_rxtx_vec_sse.c
index 6985183..a4635e0 100644
--- a/drivers/net/i40e/i40e_rxtx_vec_sse.c
+++ b/drivers/net/i40e/i40e_rxtx_vec_sse.c
@@ -86,7 +86,7 @@ i40e_rxq_rearm(struct i40e_rx_queue *rxq)
 			     (rxq->nb_rx_desc - 1) : (rxq->rxrearm_start - 1));
 
 	/* Update the tail pointer on the NIC */
-	I40E_PCI_REG_WRITE(rxq->qrx_tail, rx_id);
+	I40E_PCI_REG_WC_WRITE(rxq, rxq->qrx_tail, rx_id);
 }
 
 #ifndef RTE_LIBRTE_I40E_16BYTE_RX_DESC
@@ -733,7 +733,7 @@ i40e_xmit_fixed_burst_vec(void *tx_queue, struct rte_mbuf **tx_pkts,
 
 	txq->tx_tail = tx_id;
 
-	I40E_PCI_REG_WRITE(txq->qtx_tail, txq->tx_tail);
+	I40E_PCI_REG_WC_WRITE(txq, txq->qtx_tail, txq->tx_tail);
 
 	return nb_pkts;
 }
-- 
2.7.4



More information about the dev mailing list