[dpdk-dev] [PATCH 1/3] mbuf:add two TX offload flags and change three fields
Olivier MATZ
olivier.matz at 6wind.com
Thu Nov 27 11:00:06 CET 2014
Hi Jijiang,
Please see some comments below.
On 11/27/2014 09:18 AM, Jijiang Liu wrote:
> In place of removing the PKT_TX_VXLAN_CKSUM, we introduce 2 new flags: PKT_TX_OUT_IP_CKSUM, PKT_TX_UDP_TUNNEL_PKT, and a new field: l4_tun_len.
> Replace the inner_l2_len and the inner_l3_len field with the outer_l2_len and outer_l3_len field.
>
> PKT_TX_OUT_IP_CKSUM: is not used for non-tunnelling packet;hardware outer checksum for tunnelling packet.
> PKT_TX_UDP_TUNNEL_PKT: is used to tell PMD that the transmit packet is a UDP tunneling packet.
> l4_tun_len: for VXLAN packet, it should be udp header length plus VXLAN header length.
>
> Signed-off-by: Jijiang Liu <jijiang.liu at intel.com>
> ---
> lib/librte_mbuf/rte_mbuf.c | 2 +-
> lib/librte_mbuf/rte_mbuf.h | 23 ++++++++++++++---------
> 2 files changed, 15 insertions(+), 10 deletions(-)
>
> diff --git a/lib/librte_mbuf/rte_mbuf.c b/lib/librte_mbuf/rte_mbuf.c
> index 87c2963..e89c310 100644
> --- a/lib/librte_mbuf/rte_mbuf.c
> +++ b/lib/librte_mbuf/rte_mbuf.c
> @@ -240,7 +240,7 @@ const char *rte_get_tx_ol_flag_name(uint64_t mask)
> case PKT_TX_SCTP_CKSUM: return "PKT_TX_SCTP_CKSUM";
> case PKT_TX_UDP_CKSUM: return "PKT_TX_UDP_CKSUM";
> case PKT_TX_IEEE1588_TMST: return "PKT_TX_IEEE1588_TMST";
> - case PKT_TX_VXLAN_CKSUM: return "PKT_TX_VXLAN_CKSUM";
> + case PKT_TX_UDP_TUNNEL_PKT: return "PKT_TX_UDP_TUNNEL_PKT";
> case PKT_TX_TCP_SEG: return "PKT_TX_TCP_SEG";
> default: return NULL;
As I said as a reply to the cover letter, I suggest to use
PKT_TX_OUT_UDP_CKSUM instead of PKT_TX_UDP_TUNNEL_PKT.
Also, the PKT_TX_OUT_IP_CKSUM case is missing here.
> diff --git a/lib/librte_mbuf/rte_mbuf.h b/lib/librte_mbuf/rte_mbuf.h
> index 367fc56..48cd8e1 100644
> --- a/lib/librte_mbuf/rte_mbuf.h
> +++ b/lib/librte_mbuf/rte_mbuf.h
> @@ -99,10 +99,9 @@ extern "C" {
> #define PKT_RX_TUNNEL_IPV6_HDR (1ULL << 12) /**< RX tunnel packet with IPv6 header. */
> #define PKT_RX_FDIR_ID (1ULL << 13) /**< FD id reported if FDIR match. */
> #define PKT_RX_FDIR_FLX (1ULL << 14) /**< Flexible bytes reported if FDIR match. */
> -/* add new RX flags here */
>
We should probably not remove this line.
> /* add new TX flags here */
> -#define PKT_TX_VXLAN_CKSUM (1ULL << 50) /**< TX checksum of VXLAN computed by NIC */
> +#define PKT_TX_UDP_TUNNEL_PKT (1ULL << 50) /**< TX packet is an UDP tunneling packet */
> #define PKT_TX_IEEE1588_TMST (1ULL << 51) /**< TX IEEE1588 packet to timestamp. */
>
> /**
> @@ -125,13 +124,20 @@ extern "C" {
> #define PKT_TX_IP_CKSUM (1ULL << 54) /**< IP cksum of TX pkt. computed by NIC. */
> #define PKT_TX_IPV4_CSUM PKT_TX_IP_CKSUM /**< Alias of PKT_TX_IP_CKSUM. */
>
> +#define PKT_TX_VLAN_PKT (1ULL << 55) /**< TX packet is a 802.1q VLAN packet. */
> +
> /** Tell the NIC it's an IPv4 packet. Required for L4 checksum offload or TSO. */
> -#define PKT_TX_IPV4 PKT_RX_IPV4_HDR
> +#define PKT_TX_IPV4 (1ULL << 56)
>
> /** Tell the NIC it's an IPv6 packet. Required for L4 checksum offload or TSO. */
> -#define PKT_TX_IPV6 PKT_RX_IPV6_HDR
> +#define PKT_TX_IPV6 (1ULL << 57)
The description in comment does not match the description in the cover
letter.
Also, I think replacing PKT_RX_IPV[46]_HDR by the value may go in
another commit.
> -#define PKT_TX_VLAN_PKT (1ULL << 55) /**< TX packet is a 802.1q VLAN packet. */
> +/** Outer IP cksum of TX pkt. computed by NIC for tunneling packet */
> +#define PKT_TX_OUTER_IP_CKSUM (1ULL << 58)
> +#define PKT_TX_OUTER_IPV4_CSUM PKT_TX_OUTER_IP_CKSUM /**< Alias of PKT_TX_OUTER_IP_CKSUM. */
Why do we need an alias?
By the way, I think the alias of PKT_TX_IP_CKSUM is also uneeded and
can be removed. But it's not the topic of your series.
Also, the name PKT_TX_OUTER_IP_CKSUM does not match the name in the
cover letter and commit logs.
> +
> +/** Tell the NIC it's an outer IPv6 packet for tunneling packet.*/
> +#define PKT_TX_OUTER_IPV6 (1ULL << 59)
>
This flag is not in the cover letter or commit log. What is its purpose?
> /**
> * TCP segmentation offload. To enable this offload feature for a
> @@ -266,10 +272,9 @@ struct rte_mbuf {
> uint64_t tso_segsz:16; /**< TCP TSO segment size */
>
> /* fields for TX offloading of tunnels */
> - uint64_t inner_l3_len:9; /**< inner L3 (IP) Hdr Length. */
> - uint64_t inner_l2_len:7; /**< inner L2 (MAC) Hdr Length. */
> -
> - /* uint64_t unused:8; */
> + uint64_t outer_l3_len:9; /**< outer L3 (IP) Hdr Length. */
> + uint64_t outer_l2_len:7; /**< outer L2 (MAC) Hdr Length. */
> + uint64_t l4_tun_len:8; /**< L4 tunnelling header length */
> };
> };
> } __rte_cache_aligned;
>
About l4_tun_len, I have another comment I forgot to add in the cover
letter. Can we remove it and include its length in outer_l2_len
instead? For instance, replace:
mb->l2_len = eth_hdr_in;
mb->l3_len = ipv4_hdr_in;
mb->outer_l2_len = eth_hdr_out;
mb->outer_l3_len = ipv4_hdr_out;
mb->l4tun_len = vxlan_hdr;
mb->ol_flags |= PKT_TX_OUT_IP_CKSUM | PKT_TX_UDP_TUNNEL |
PKT_TX_IP_CKSUM | PKT_TX_TCP_CKSUM;
by:
mb->l2_len = eth_hdr_in;
mb->l3_len = ipv4_hdr_in;
mb->outer_l2_len = eth_hdr_out + vxlan_hdr;
mb->outer_l3_len = ipv4_hdr_out;
mb->ol_flags |= PKT_TX_OUT_IP_CKSUM | PKT_TX_UDP_TUNNEL |
PKT_TX_IP_CKSUM | PKT_TX_TCP_CKSUM;
I think it won't bother the driver, and it's coherent with case B.2 of
your cover letter.
Regards,
Olivier
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