Re: [PATCH net] geneve: initialize needed_headroom

2015-12-23 Thread Paolo Abeni 
On Wed, 2015-12-23 at 16:35 +0100, Hannes Frederic Sowa wrote:
> On 23.12.2015 16:21, Paolo Abeni wrote:
> > @@ -1187,6 +1187,14 @@ static int geneve_configure(struct net *net, struct 
> > net_device *dev,
> > if (t)
> > return -EBUSY;
> >  
> > +   /* make enough headroom for basic scenario */
> > +   encap_len = GENEVE_BASE_HLEN + ETH_HLEN;
> > +   if (remote->sa.sa_family == AF_INET)
> > +   encap_len += sizeof(struct iphdr);
> > +   else
> > +   encap_len += sizeof(struct ipv6hdr);
> > +   dev->needed_headroom = encap_len;
> > +
> 
> We are missing one time ETH_HLEN or hard_header_len of the lower_dev (if
> available) in here AFAIK.

You are right. Most probably performance numbers where good even with
the missing ETH_HLEN due to some rounding. I'll send a v2.

Paolo

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Re: [PATCH net] geneve: initialize needed_headroom

2015-12-23 Thread John W. Linville 
On Wed, Dec 23, 2015 at 04:21:48PM +0100, Paolo Abeni wrote:
> Currently the needed_headroom field for the geneve device is left
> to the default value.
> 
> This patch set it to space required for basic geneve encapsulation,
> so that we can avoid the skb head re-allocation on xmit.
> 
> This give a 6% speedup for unsegment traffic on geneve tunnel.
> 
> Signed-off-by: Paolo Abeni 
> Acked-by: Hannes Frederic Sowa 

Acked-by: John W. Linville 

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Re: [PATCH net] geneve: initialize needed_headroom

2015-12-23 Thread Hannes Frederic Sowa 
On 23.12.2015 16:21, Paolo Abeni wrote:
> Currently the needed_headroom field for the geneve device is left
> to the default value.
> 
> This patch set it to space required for basic geneve encapsulation,
> so that we can avoid the skb head re-allocation on xmit.
> 
> This give a 6% speedup for unsegment traffic on geneve tunnel.
> 
> Signed-off-by: Paolo Abeni 
> Acked-by: Hannes Frederic Sowa 

(Sorry, just saw this.)

> ---
>  drivers/net/geneve.c | 10 +-
>  1 file changed, 9 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/geneve.c b/drivers/net/geneve.c
> index c2b79f5..bb3e6ed 100644
> --- a/drivers/net/geneve.c
> +++ b/drivers/net/geneve.c
> @@ -1155,7 +1155,7 @@ static int geneve_configure(struct net *net, struct 
> net_device *dev,
>   struct geneve_net *gn = net_generic(net, geneve_net_id);
>   struct geneve_dev *t, *geneve = netdev_priv(dev);
>   bool tun_collect_md, tun_on_same_port;
> - int err;
> + int err, encap_len;
>  
>   if (!remote)
>   return -EINVAL;
> @@ -1187,6 +1187,14 @@ static int geneve_configure(struct net *net, struct 
> net_device *dev,
>   if (t)
>   return -EBUSY;
>  
> + /* make enough headroom for basic scenario */
> + encap_len = GENEVE_BASE_HLEN + ETH_HLEN;
> + if (remote->sa.sa_family == AF_INET)
> + encap_len += sizeof(struct iphdr);
> + else
> + encap_len += sizeof(struct ipv6hdr);
> + dev->needed_headroom = encap_len;
> +

We are missing one time ETH_HLEN or hard_header_len of the lower_dev (if
available) in here AFAIK.

Thanks,
Hannes

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