bcm63xx: batch process RX path

Use netif_receive_skb_list to batch process skb in RX.
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>
[Amend commit description]
Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>

diff --git a/target/linux/bcm63xx/patches-5.4/440-bcm63xx_enet-batch_process_RX_path.patch b/target/linux/bcm63xx/patches-5.4/440-bcm63xx_enet-batch_process_RX_path.patch
new file mode 100644 (file)
index 0000000..0a22d8c
--- /dev/null
+++ b/target/linux/bcm63xx/patches-5.4/440-bcm63xx_enet-batch_process_RX_path.patch
@@ -0,0 +1,53 @@
+From 1606f78dc82e4f311ca5844a0605a62cd141a072 Mon Sep 17 00:00:00 2001
+From: Sieng Piaw Liew <liew.s.piaw@gmail.com>
+Date: Mon, 30 Nov 2020 11:07:47 +0800
+Subject: [PATCH] bcm63xx: batch process RX path
+
+Use netif_receive_skb_list to batch process skb in RX.
+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>
+---
+ 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
+@@ -301,10 +301,12 @@ static int bcm_enet_receive_queue(struct
+       struct bcm_enet_priv *priv;
+       struct device *kdev;
+       int processed;
++      struct list_head rx_list;
+ 
+       priv = netdev_priv(dev);
+       kdev = &priv->pdev->dev;
+       processed = 0;
++      INIT_LIST_HEAD(&rx_list);
+ 
+       /* don't scan ring further than number of refilled
+        * descriptor */
+@@ -393,10 +395,12 @@ 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);
+