[dpdk-dev] [PATCH v3 1/3] fm10k: enable FTAG based forwarding

Chen, Jing D jing.d.chen at intel.com
Thu Feb 25 11:04:02 CET 2016


Hi, Bruce, Thomas,

Best Regards,
Mark

> -----Original Message-----
> From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Thomas Monjalon
> Sent: Thursday, February 25, 2016 12:38 AM
> To: Richardson, Bruce; Wang, Xiao W
> Cc: dev at dpdk.org
> Subject: Re: [dpdk-dev] [PATCH v3 1/3] fm10k: enable FTAG based
> forwarding
> 
> 2016-02-24 15:42, Bruce Richardson:
> > On Thu, Feb 04, 2016 at 11:38:47AM +0800, Wang Xiao W wrote:
> > > This patch enables reading sglort info into mbuf for RX and inserting
> > > an FTAG at the beginning of the packet for TX. The vlan_tci_outer field
> > > selected from rte_mbuf structure for sglort is not used in fm10k now.
> > > In FTAG based forwarding mode, the switch will forward packets
> according
> > > to glort info in FTAG rather than mac and vlan table.
> > >
> > > To activate this feature, user needs to turn
> ``CONFIG_RTE_LIBRTE_FM10K_FTAG_FWD``
> > > to y in common_linuxapp or common_bsdapp. Currently this feature is
> supported
> > > only on PF, because FM10K_PFVTCTL register is read-only for VF.
> > >
> > > Signed-off-by: Wang Xiao W <xiao.w.wang at intel.com>
> >
> > Any comments on this patch?
> >
> > My thoughts: is there a way in which this could be done without adding in a
> new
> > build time config option?
> 
> Bruce, it's simpler to explain that build time options are forbidden to
> enable such options.
> Or the terrific kid's approach: one day, the Big Build-Option Eater will come
> and will eat every undecided features! ;)

This feature is trying to use FTAG (a unique tech in fm10k) instead of mac/vlan
to forward packets. App need a way to tell PMD driver that which forwarding
style it would like to use. 
So, the best option is to let packets carry a flag in mbuf to tell drive in fast path. 
You can see that this is unique to fm10k and we thought community won't like to see 
this flag introduced into mbuf. If you do agree, we can introduce a new flag.
So, we step backwards and assume customer will use static configurations to enable
this feature. After it is enabled, we'll assume app will use FTAG for all packets.


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