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[03/10] net/enetc: batch process enetc clean Tx ring calls

Message ID 20200302143209.11854-4-hemant.agrawal@nxp.com
State New
Headers show
Series net/enetc: optimization and cleanup | expand

Commit Message

Hemant Agrawal March 2, 2020, 2:32 p.m. UTC 
From: Alex Marginean <alexandru.marginean@nxp.com>


Each call to enetc_clean_tx_ring will cost at least 150-200 CPU cycles
even if no clean-up is done, due to the CI register read.
We're only calling it once at the end of the function, on the assumption
that software is slower than hardware and hardware completed sending older
frames out by now.
We're also cleaning up the ring before kicking off Tx for the new batch to
minimize chances of contention on the Tx ring.

Signed-off-by: Alex Marginean <alexandru.marginean@nxp.com>

---
 drivers/net/enetc/enetc_rxtx.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

-- 
2.17.1
diff mbox series

Patch

diff --git a/drivers/net/enetc/enetc_rxtx.c b/drivers/net/enetc/enetc_rxtx.c
index 395f5ecf4..958e3a21d 100644
--- a/drivers/net/enetc/enetc_rxtx.c
+++ b/drivers/net/enetc/enetc_rxtx.c
@@ -76,7 +76,6 @@  enetc_xmit_pkts(void *tx_queue,
 
 	start = 0;
 	while (nb_pkts--) {
-		enetc_clean_tx_ring(tx_ring);
 		tx_ring->q_swbd[i].buffer_addr = tx_pkts[start];
 		txbd = ENETC_TXBD(*tx_ring, i);
 		tx_swbd = &tx_ring->q_swbd[i];
@@ -92,6 +91,14 @@  enetc_xmit_pkts(void *tx_queue,
 			i = 0;
 	}
 
+	/* we're only cleaning up the Tx ring here, on the assumption that
+	 * software is slower than hardware and hardware completed sending
+	 * older frames out by now.
+	 * We're also cleaning up the ring before kicking off Tx for the new
+	 * batch to minimize chances of contention on the Tx ring
+	 */
+	enetc_clean_tx_ring(tx_ring);
+
 	tx_ring->next_to_use = i;
 	enetc_wr_reg(tx_ring->tcir, i);
 	return start;