Hi Jijiang, On 11/28/2014 09:54 AM, Liu, Jijiang wrote: >>> My understanding of the meaning of the flags is: >>> >>> - PKT_TX_IP_CKSUM: tell the NIC to compute IP cksum > >> My initial thought: >> It tells the NIC that it is an IPV4 packet for which it has to compute >> checksum. >> >>> >>> - PKT_TX_IPV4: tell the NIC it's an IPv4 packet. Required for L4 >>> checksum offload or TSO. >> >> It tells the NIC that it is an IPV4 packet for which it shouldn't compute >> checksum. >> >>> >>> - PKT_TX_IPV6: tell the NIC it's an IPv6 packet. Required for L4 >>> checksum offload or TSO. >> >> Yes. >> >>> >>> If it's a i40e driver requirement, don't you think it's better to >>> change the driver? > > There should be two logics in csum engine, which is that either HW computes > TX checksum (using PKT_TX_IP_CKSUM) or SW compute TX checksum(use > PKT_TX_IPV4(or another flag) to tell driver no IP checksum offload > requirement ),
To me it's strange to have a flag saying "it's ipv4 and do the checksum" and another one saying "it's ipv4 and don't do the checksum". We can clearly see we have 2 different things to know about the packet: - is it ipv4? - do we want the hw checksum? I think that mapping the flags on these 2 questions is the most logical. > I think we shouldn't use L3 flag to tell driver what HW need do for L4, L3 > and L4 flag should be separated . What L4 operation are you talking about? Regards, Olivier
