> -----Original Message----- > From: Liu, Jijiang > Sent: Thursday, December 04, 2014 2:08 AM > To: Olivier MATZ > Cc: Ananyev, Konstantin; dev at dpdk.org > Subject: RE: [dpdk-dev] [PATCH v5 2/3] mbuf:add three TX ol_flags and repalce > PKT_TX_VXLAN_CKSUM > > Hi Olivier, > > > > -----Original Message----- > > From: Olivier MATZ [mailto:olivier.matz at 6wind.com] > > Sent: Wednesday, December 3, 2014 10:42 PM > > To: Ananyev, Konstantin; Liu, Jijiang; dev at dpdk.org > > Subject: Re: [dpdk-dev] [PATCH v5 2/3] mbuf:add three TX ol_flags and > > repalce > > PKT_TX_VXLAN_CKSUM > > > > Hi Konstantin, > > > > On 12/03/2014 01:59 PM, Ananyev, Konstantin wrote: > > >> I still think having a flag IPV4 + another flag IP_CHECKSUM is not > > >> appropriate. > > > > > > Sorry, didn't get you here. > > > Are you talking about our discussion should PKT_TX_IP_CKSUM and > > PKT_TX_IPV4 be mutually exclusive or not? > > > > Yes > > > > >> I though Konstantin agreed on other flags, but I may have > > >> misunderstood: > > >> > > >> http://dpdk.org/ml/archives/dev/2014-November/009070.html > > > > > > In that mail, I was talking about my suggestion to make PKT_TX_IP_CKSUM, > > PKT_TX_IPV4 and PKT_TX_IPV6 to occupy 2 bits. > > > Something like: > > > #define PKT_TX_IP_CKSUM (1 << X) > > > #define PKT_TX_IPV6 (2 << X) > > > #define PKT_TX_IPV4 (3 << X) > > > > > > "Even better, if we can squeeze these 3 flags into 2 bits. > > > Would save us 2 bits, plus might be handy, as in the PMD you can do: > > > > > > switch (ol_flags & TX_L3_MASK) { > > > case TX_IPV4: > > > ... > > > break; > > > case TX_IPV6: > > > ... > > > break; > > > case TX_IP_CKSUM: > > > ... > > > break; > > > }" > > > > > > As you pointed out, it will break backward compatibility. > > > I agreed with that and self-NACKed it. > > > > ok, so we are back between: > > > > 1/ (Jijiang's patch) > > PKT_TX_IP_CKSUM /* packet is IPv4, and we want hw cksum */ > > PKT_TX_IPV6 /* packet is IPv6 */ > > PKT_TX_IPV4 /* packet is IPv4, and we don't want hw cksum */ > > > > with PKT_TX_IP_CKSUM and PKT_TX_IPV4 exclusive > > > > and > > > > 2/ > > PKT_TX_IP_CKSUM /* we want hw IP cksum */ > > PKT_TX_IPV6 /* packet is IPv6 */ > > PKT_TX_IPV4 /* packet is IPv4 */ > > > > with PKT_TX_IP_CKSUM implies PKT_TX_IPV4 > > > > > > Solution 2/ looks better from a user point of view. Anyone else has an > > opinion? > > Let's think about these IPv4/6 flags in terms of checksum and IP version/type, > > 1. For IPv6 > IP checksum is meaningful only for IPv4, so we define 'PKT_TX_IPV6 /* > packet is IPv6 */' to tell driver/HW that this is IPV6 packet, > here we don't talk about the checksum for IPv6 as it is meaningless. Right? > > PKT_TX_IPV6 /* packet is IPv6 */ ------ IP type: v6; HW > checksum: meaningless > > 2. For IPv4, > My patch: > > PKT_TX_IP_CKSUM /* packet is IPv4, and we want hw cksum > */--------------------------IP type: v4; HW checksum: Yes > PKT_TX_IPV4 /* packet is IPv4, and we don't want hw cksum */ > ----------------------- IP type: v4; HW checksum: No > > You want: > PKT_TX_IP_CKSUM /* we want hw IP cksum */-------------------------- IP type: > v4; HW checksum: Yes > PKT_TX_IPV4 /* packet is IPv4*/ ------------------------ IP type: v4; > HW checksum: yes or no? > > driver/HW don't know, just know this is packet with > IPv4 header. > > HW checksum: meaningless??
Yep, that's why I also don't like that suggestion: PKT_TX_IPV4 itself doesn't contain all information. PMD will have to check PKT_TX_IP_CKSUM anyway. Konstantin > > > Regards, > > Olivier
