Re: [RFC] be2net: add rxhash support

[Eric Dumazet <eric.dumazet@gmail.com>]

Le vendredi 25 février 2011 à 11:44 -0600, Ajit Khaparde a écrit :
> > -----Original Message-----
> > From: Eric Dumazet <eric.dumazet@gmail.com>
> > Sent: Thursday, February 24, 2011 2:25 PM
> > To: Khaparde, Ajit
> > Cc: netdev@vger.kernel.org
> > Subject: [RFC] be2net: add rxhash support
> > 
> > Ajit, it seems be2net provides RSS hash value in rx compl descriptor ?
> > 
> > Could we feed skb->rxhash with it ?
> > 
> > Thanks !
> Thanks Eric. Sure.
> This is a long pending change which fell through the cracks.
> But then because hashing is enabled in the device only when
> Number of Rx Queues is > 1, I would suggest the following patch.
> 
> Unaware of exact conventions, I have added signed-off-by to the patch already.
> 
> Thanks
> 
> -----
> [PATCH net-next] be2net: add rxhash support
> 
> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
> Signed-off-by: Ajit Khaparde <ajit.khaparde@emulex.com>
> ---
>  drivers/net/benet/be_main.c |   11 +++++++++++
>  1 files changed, 11 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/net/benet/be_main.c b/drivers/net/benet/be_main.c
> index 26f9c56..8c4b782 100644
> --- a/drivers/net/benet/be_main.c
> +++ b/drivers/net/benet/be_main.c
> @@ -1038,6 +1038,10 @@ static void be_rx_compl_process(struct be_adapter *adapter,
>  
>  	skb->truesize = skb->len + sizeof(struct sk_buff);
>  	skb->protocol = eth_type_trans(skb, adapter->netdev);
> +	if (adapter->netdev->features & NETIF_F_RXHASH)
> +		skb->rxhash = AMAP_GET_BITS(struct amap_eth_rx_compl,
> +					rsshash, rxcp);
> +
>  
>  	vlanf = AMAP_GET_BITS(struct amap_eth_rx_compl, vtp, rxcp);
>  	vtm = AMAP_GET_BITS(struct amap_eth_rx_compl, vtm, rxcp);
> @@ -1099,6 +1103,10 @@ static void be_rx_compl_process_gro(struct be_adapter *adapter,
>  		return;
>  	}
>  
> +	if (adapter->netdev->features & NETIF_F_RXHASH)
> +		skb->rxhash = AMAP_GET_BITS(struct amap_eth_rx_compl,
> +						rsshash, rxcp);
> +
>  	remaining = pkt_size;
>  	for (i = 0, j = -1; i < num_rcvd; i++) {
>  		page_info = get_rx_page_info(adapter, rxo, rxq_idx);
> @@ -2619,6 +2627,9 @@ static void be_netdev_init(struct net_device *netdev)
>  		NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM |
>  		NETIF_F_GRO | NETIF_F_TSO6;
>  
> +	if (be_multi_rxq(adapter))
> +		netdev->features |= NETIF_F_RXHASH;
> +
>  	netdev->vlan_features |= NETIF_F_SG | NETIF_F_TSO |
>  		NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM;
>  


I added some traces, and I am not sure its OK :

With one active tcp flow, I got different rxhash values :

[ 1064.674253] rxhash=bbd37952 rsshp=1 bank=1
[ 1064.738104] rxhash=37acd31d rsshp=1 bank=1
[ 1064.741684] rxhash=bbd37952 rsshp=1 bank=1
[ 1064.874283] rxhash=bbd37952 rsshp=1 bank=1
[ 1064.940201] rxhash=bbd37952 rsshp=1 bank=1
[ 1064.955278] rxhash=b668ace2 rsshp=1 bank=1
[ 1065.080028] rxhash=bbd37952 rsshp=1 bank=1
[ 1065.153360] rxhash=bbd37952 rsshp=1 bank=1
[ 1065.293164] rxhash=bbd37952 rsshp=1 bank=1
[ 1065.401862] rxhash=bbd37952 rsshp=1 bank=1
[ 1065.460506] rxhash=bbd37952 rsshp=1 bank=1
[ 1065.519980] rxhash=bbd37952 rsshp=1 bank=1
[ 1065.650160] rxhash=bbd37952 rsshp=1 bank=1
[ 1065.717585] rxhash=bbd37952 rsshp=1 bank=1
[ 1065.730909] rxhash=37acd31d rsshp=1 bank=1
[ 1065.840350] rxhash=bbd37952 rsshp=1 bank=1
[ 1065.900704] rxhash=bbd37952 rsshp=1 bank=1
[ 1065.931526] rxhash=b668ace2 rsshp=1 bank=1
[ 1066.503657] rxhash=bbd37952 rsshp=1 bank=1
[ 1066.570138] rxhash=bbd37952 rsshp=1 bank=1

How is it possible ?

(I have a VLAN config on top of a bonding)