On Thu, Feb 25, 2016 at 03:45:45PM +0000, Chen, Jing D wrote: > Hi, Bruce, > > > -----Original Message----- > > From: Richardson, Bruce > > Sent: Thursday, February 25, 2016 9:35 PM > > To: Chen, Jing D <jing.d.chen at intel.com> > > Cc: Thomas Monjalon <thomas.monjalon at 6wind.com>; Wang, Xiao W > > <xiao.w.wang at intel.com>; dev at dpdk.org > > Subject: Re: [dpdk-dev] [PATCH v3 1/3] fm10k: enable FTAG based > > forwarding > > > > On Thu, Feb 25, 2016 at 10:04:02AM +0000, Chen, Jing D wrote: > > > 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. > > > > Why not just specify this in the port configuration at setup time? > > > > Please educate me. I think the port configuration flags are also common to > all PMD > Drivers. Is it possible to add a flag like "RTE_USE_FTAG" and pass to PMD > driver? > They are. For something PMD specific, like FTAG, it's always a challenge, and I don't know off the top of my head if there is a simple option. However, given the choice between an mbuf flag and a port config flag, I'd always choose the former. Other alternatives would be to have a fm10k specific API in the fm10k driver alone.
I'll let Thomas as ethdev maintainer comment if he has other suggestions as to how to handle this case. I suspect this won't be the first device-specific piece of functionality we need to deal with. /Bruce
