[PATCH net-next v3 4/7] bcm63xx_enet: alloc rx skb with NET_IP_ALIGN

Sieng Piaw Liew
2021-01-06T14:44:24Z

Use netdev_alloc_skb_ip_align on newer SoCs with integrated switch
(enetsw) when refilling RX. Increases packet processing performance
by 30% (with netif_receive_skb_list).

Non-enetsw SoCs cannot function with the extra pad so continue to use
the regular netdev_alloc_skb.

Tested on BCM6328 320 MHz and iperf3 -M 512 to measure packet/sec
performance.

Before:
[ ID] Interval Transfer Bandwidth Retr
[ 4] 0.00-30.00 sec 120 MBytes 33.7 Mbits/sec 277 sender
[ 4] 0.00-30.00 sec 120 MBytes 33.5 Mbits/sec receiver

After (+netif_receive_skb_list):
[ 4] 0.00-30.00 sec 155 MBytes 43.3 Mbits/sec 354 sender
[ 4] 0.00-30.00 sec 154 MBytes 43.1 Mbits/sec receiver

Signed-off-by: Sieng Piaw Liew <liew.s.piaw@gmail.com>
---
drivers/net/ethernet/broadcom/bcm63xx_enet.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/broadcom/bcm63xx_enet.c b/drivers/net/ethernet/broadcom/bcm63xx_enet.c
index 21744dae30ce..96d56c3e2cc9 100644
--- a/drivers/net/ethernet/broadcom/bcm63xx_enet.c
+++ b/drivers/net/ethernet/broadcom/bcm63xx_enet.c
@@ -237,7 +237,10 @@ static int bcm_enet_refill_rx(struct net_device *dev)
desc = &priv->rx_desc_cpu[desc_idx];

if (!priv->rx_skb[desc_idx]) {
- skb = netdev_alloc_skb(dev, priv->rx_skb_size);
+ if (priv->enet_is_sw)
+ skb = netdev_alloc_skb_ip_align(dev, priv->rx_skb_size);
+ else
+ skb = netdev_alloc_skb(dev, priv->rx_skb_size);
if (!skb)
break;
priv->rx_skb[desc_idx] = skb;
--
2.17.1