> -----Original Message----- > From: Ananyev, Konstantin > Sent: Thursday, November 27, 2014 12:35 AM > To: Olivier MATZ; dev at dpdk.org > Cc: Walukiewicz, Miroslaw; Liu, Jijiang; Liu, Yong; jigsaw at gmail.com; > Richardson, > Bruce > Subject: RE: [PATCH v3 08/13] testpmd: rework csum forward engine > > Hi Oliver, > > > -----Original Message----- > > From: Olivier MATZ [mailto:olivier.matz at 6wind.com] > > Sent: Wednesday, November 26, 2014 2:55 PM > > To: Ananyev, Konstantin; dev at dpdk.org > > Cc: Walukiewicz, Miroslaw; Liu, Jijiang; Liu, Yong; jigsaw at gmail.com; > > Richardson, Bruce > > Subject: Re: [PATCH v3 08/13] testpmd: rework csum forward engine > > > > Hi Konstantin, > > > > On 11/26/2014 01:25 PM, Ananyev, Konstantin wrote: > > >> By the way (this is probably off-topic), but I'm wondering if the > > >> TX flags should have the same values than the RX flags: > > >> > > >> #define PKT_TX_IPV4 PKT_RX_IPV4_HDR > > >> #define PKT_TX_IPV6 PKT_RX_IPV6_HDR > > > > > > Thought about that too. > > > From one side, it is a bit out of our concept: separate RX and TX falgs. > > > From other side, it allows us to save 2 bits in the ol_flags. > > > Don't have any strong opinion here. > > > What do you think? > > > > I have no strong opinion too, but I have a preference for 2 different > > bit values for these flags: > > > > - as you say, it's matches the concept (RX and TX flags are separated) > > > > - 64 bits is a lot, we have some time before there is no more available > > bit... and I hope we it will never occur because it would become > > complex for an application to handle them all > > > > - it will avoid to send a packet with a bad info: > > - we receive a Ether/IP6/IP4/L4/data packet > > - the driver sets PKT_RX_IPV6_HDR > > - the stack decapsulates IP6 > > - the stack sends the packet, it has the PKT_TX_IPV6 flag but it's an > > IPv4 packet > > Ah yes, you right, if we keep them the same, then upper layer always has to > clear > PKT_RX_IPV4_HDR | PKT_RX_IPV6_HDR before setting TX offload flags and > passing packet to the PMD for TX. > And if the upper layer wouldn't do that - it might cause a problem. > With your example above - if at last step the stack sets PKT_TX_IP_CKSUM for > the packet, then PMD will receive an mbuf with (PKT_TX_IPV6 | > PKT_TX_IP_CKSUM) set. > Though from PKT_TX_IP_CKSUM/ PKT_TX_IPV6/ PKT_TX_IPV4 only one can be > set, as they are mutually exclusive. > So i40e PMD will get confused and might not be able to arm TX descriptor > propely. > So yes, we need to make them a proper TX flags.
I have changed definitions of the two flags in the patch of rework VXLAN TX checksum. > Thanks for spotting it. > Konstantin > > > > > This is not a real problem as the flag will not be used by the > > driver/hardware (it's only mandatory for hw cksum / tso), but > > it can be confusing. > > > > Regards, > > Olivier > >
