[Cbe-oss-dev] [PATCH 1/2 v2] PS3: changed the way to handle tx skbs

Jeff Garzik jeff at garzik.org
Fri Aug 31 23:59:57 EST 2007


Masakazu Mokuno wrote:
> The PS3 virtual network device requires a vlan tag in the sending packet
> to select the destination device, ethernet port or wireless. 
> As the vlan tag field is in the middle of the passed data, 
> we should insert it into the packet data.
> To avoid copying much of the packet data, the driver used two tx descriptors
> for one tx skb; one descriptor was for sending a small static 
> buffer which contained vlan tag and copied header (two mac addresses),
> one was for the residual data after the vlan field.
> 
> This patch changes the way to insert the vlan tag.  By changing 
> netdev->hard_header_len, we can make the headroom for moving mac address
> fields in the skb buffer. Then we can send one tx skb with
> one tx descriptor.  This also gives us a tx throughut gain of approx.
> 20% according to netperf results.
> 
> Signed-off-by: Masakazu Mokuno <mokuno at sm.sony.co.jp>
> CC: Geoff Levand <geoffrey.levand at am.sony.com>
> ---
>  drivers/net/ps3_gelic_net.c |  140 +++++++++++++++++++-------------------------
>  1 file changed, 63 insertions(+), 77 deletions(-)

applied 1-2, thanks for the update





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