openwrt/target/linux/bcm63xx/patches-5.4/043-v5.12-bcm63xx_enet-alloc-rx-skb-with-NET_IP_ALIGN.patch

From c4a207865e7ea310dc146ff4aa1b0aa0c78d3fe1 Mon Sep 17 00:00:00 2001
From: Sieng Piaw Liew <liew.s.piaw@gmail.com>
Date: Wed, 6 Jan 2021 22:42:05 +0800
Subject: [PATCH 4/7] bcm63xx_enet: alloc rx skb with NET_IP_ALIGN

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>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
 drivers/net/ethernet/broadcom/bcm63xx_enet.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

--- a/drivers/net/ethernet/broadcom/bcm63xx_enet.c
+++ b/drivers/net/ethernet/broadcom/bcm63xx_enet.c
@@ -238,7 +238,10 @@ static int bcm_enet_refill_rx(struct net
 		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;