From 9a6d2fae261c64dabbafc981acb8a2940f750204 Mon Sep 17 00:00:00 2001 From: Alex Marginean Date: Mon, 2 Mar 2020 20:02:02 +0530 Subject: [PATCH] net/enetc: batch process clean Tx ring calls 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 Acked-by: Gagandeep Singh --- drivers/net/enetc/enetc_rxtx.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/drivers/net/enetc/enetc_rxtx.c b/drivers/net/enetc/enetc_rxtx.c index 395f5ecf41..958e3a21d8 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;