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? > > 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. > > Why does it need to be specified per-mbuf? The existing config flag added is > global, so a per-mbuf flag shouldn't be needed to get equivalent behaviour. > > > 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. > > Yes, but instead of compile time option, why not port config-time option > instead? > > /Bruce
