Thread (6 messages) 6 messages, 2 authors, 2023-05-17
STALE1127d REVIEWED: 1 (0M)

[PATCH] net/i40e: remove redundant judgment for rearm

From: Feifei Wang <hidden>
Date: 2021-12-20 05:42:58
Subsystem: networking drivers, the rest · Maintainers: Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds

Merged variable updates under the same condition. It reduces branch.

In n1sdp, there is no performance improvement with this patch.
In x86, there is also no performance improvement.

Suggested-by: Honnappa Nagarahalli <redacted>
Signed-off-by: Feifei Wang <redacted>
Reviewed-by: Ruifeng Wang <redacted>
---
 drivers/net/i40e/i40e_rxtx_vec_neon.c | 9 +++++----
 drivers/net/i40e/i40e_rxtx_vec_sse.c  | 9 +++++----
 2 files changed, 10 insertions(+), 8 deletions(-)
diff --git a/drivers/net/i40e/i40e_rxtx_vec_neon.c b/drivers/net/i40e/i40e_rxtx_vec_neon.c
index b951ea2dc3..c7e4222b61 100644
--- a/drivers/net/i40e/i40e_rxtx_vec_neon.c
+++ b/drivers/net/i40e/i40e_rxtx_vec_neon.c
@@ -64,14 +64,15 @@ i40e_rxq_rearm(struct i40e_rx_queue *rxq)
 	}
 
 	rxq->rxrearm_start += RTE_I40E_RXQ_REARM_THRESH;
-	if (rxq->rxrearm_start >= rxq->nb_rx_desc)
+	rx_id = rxq->rxrearm_start - 1;
+
+	if (unlikely(rxq->rxrearm_start >= rxq->nb_rx_desc)) {
 		rxq->rxrearm_start = 0;
+		rx_id = rxq->nb_rx_desc - 1;
+	}
 
 	rxq->rxrearm_nb -= RTE_I40E_RXQ_REARM_THRESH;
 
-	rx_id = (uint16_t)((rxq->rxrearm_start == 0) ?
-			     (rxq->nb_rx_desc - 1) : (rxq->rxrearm_start - 1));
-
 	rte_io_wmb();
 	/* Update the tail pointer on the NIC */
 	I40E_PCI_REG_WRITE_RELAXED(rxq->qrx_tail, rx_id);
diff --git a/drivers/net/i40e/i40e_rxtx_vec_sse.c b/drivers/net/i40e/i40e_rxtx_vec_sse.c
index 497b2404c6..0910039d69 100644
--- a/drivers/net/i40e/i40e_rxtx_vec_sse.c
+++ b/drivers/net/i40e/i40e_rxtx_vec_sse.c
@@ -77,14 +77,15 @@ i40e_rxq_rearm(struct i40e_rx_queue *rxq)
 	}
 
 	rxq->rxrearm_start += RTE_I40E_RXQ_REARM_THRESH;
-	if (rxq->rxrearm_start >= rxq->nb_rx_desc)
+	rx_id = rxq->rxrearm_start - 1;
+
+	if (unlikely(rxq->rxrearm_start >= rxq->nb_rx_desc)) {
 		rxq->rxrearm_start = 0;
+		rx_id = rxq->nb_rx_desc - 1;
+	}
 
 	rxq->rxrearm_nb -= RTE_I40E_RXQ_REARM_THRESH;
 
-	rx_id = (uint16_t)((rxq->rxrearm_start == 0) ?
-			     (rxq->nb_rx_desc - 1) : (rxq->rxrearm_start - 1));
-
 	/* Update the tail pointer on the NIC */
 	I40E_PCI_REG_WC_WRITE(rxq->qrx_tail, rx_id);
 }
-- 
2.25.1
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