openwrt/target/linux/bcm63xx/patches-5.10/020-v5.12-bcm63xx_enet-batch-process-rx-path.patch

From 9cbfea02c1dbee0afb9128f065e6e793672b9ff7 Mon Sep 17 00:00:00 2001
From: Sieng Piaw Liew <liew.s.piaw@gmail.com>
Date: Wed, 6 Jan 2021 22:42:02 +0800
Subject: [PATCH 1/7] bcm63xx_enet: batch process rx path

Use netif_receive_skb_list to batch process rx skb.
Tested on BCM6328 320 MHz using iperf3 -M 512, increasing performance
by 12.5%.

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:
[ ID] Interval           Transfer     Bandwidth       Retr
[  4]   0.00-30.00  sec   136 MBytes  37.9 Mbits/sec  203         sender
[  4]   0.00-30.00  sec   135 MBytes  37.7 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 | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

--- a/drivers/net/ethernet/broadcom/bcm63xx_enet.c
+++ b/drivers/net/ethernet/broadcom/bcm63xx_enet.c
@@ -297,10 +297,12 @@ static void bcm_enet_refill_rx_timer(str
 static int bcm_enet_receive_queue(struct net_device *dev, int budget)
 {
 	struct bcm_enet_priv *priv;
+	struct list_head rx_list;
 	struct device *kdev;
 	int processed;
 
 	priv = netdev_priv(dev);
+	INIT_LIST_HEAD(&rx_list);
 	kdev = &priv->pdev->dev;
 	processed = 0;
 
@@ -391,10 +393,12 @@ static int bcm_enet_receive_queue(struct
 		skb->protocol = eth_type_trans(skb, dev);
 		dev->stats.rx_packets++;
 		dev->stats.rx_bytes += len;
-		netif_receive_skb(skb);
+		list_add_tail(&skb->list, &rx_list);
 
 	} while (--budget > 0);
 
+	netif_receive_skb_list(&rx_list);
+
 	if (processed || !priv->rx_desc_count) {
 		bcm_enet_refill_rx(dev);