Re: [PATCH net-next] xen-netfront: convert to GRO API and advertise this feature
From: Eric Dumazet <hidden>
Date: 2013-09-23 05:58:29
On Sun, 2013-09-22 at 23:09 +0000, Anirban Chakraborty wrote:
On Sep 22, 2013, at 7:55 AM, Eric Dumazet [off-list ref] wrote:quoted
On Sat, 2013-09-21 at 17:05 +0100, Wei Liu wrote:quoted
Anirban was seeing netfront received MTU size packets, which downgraded throughput. The following patch makes netfront use GRO API which improves throughput for that case.quoted
- netdev->hw_features = NETIF_F_IP_CSUM | NETIF_F_SG | NETIF_F_TSO; + netdev->hw_features = NETIF_F_IP_CSUM | NETIF_F_SG | NETIF_F_TSO | + NETIF_F_GRO;This part is not needed.Shouldn't the flag be set? In dev_gro_receive() we do check if this flag is set or not: if (!(skb->dev->features & NETIF_F_GRO) || netpoll_rx_on(skb)) goto normal;
Drivers do not set NETIF_F_GRO themselves, they do not need to. Look at other drivers which are GRO ready : NETIF_F_GRO is enabled by default by core networking stack, in register_netdevice() dev->hw_features |= NETIF_F_SOFT_FEATURES; dev->features |= NETIF_F_SOFT_FEATURES;