[ovs-dev] netdev-dpdk: Memset rte_flow_item on a need basis.

Ilya Maximets i.maximets at samsung.com
Mon Feb 4 14:13:36 UTC 2019


On 04.02.2019 15:50, Asaf Penso wrote:
> In netdev_dpdk_add_rte_flow_offload function different rte_flow_item are
> created as part of the pattern matching.
> 
> For most of them, there is a check whether the wildcards are not zero.
> In case of zero, nothing is being done with the rte_flow_item.
> 
> Befor the wildcard check, and regardless of the result, the
> rte_flow_item is being memset.
> 
> The patch moves the memset function only if the condition of the
> wildcard is true, thus saving cycles of memset if not needed.

Structures are actually used only inside their 'if' blocks.
IMHO, it's better to move the definitions inside too.

> 
> Signed-off-by: Asaf Penso <asafp at mellanox.com>
> ---
>  lib/netdev-dpdk.c | 28 ++++++++++++++--------------
>  1 file changed, 14 insertions(+), 14 deletions(-)
> 
> diff --git a/lib/netdev-dpdk.c b/lib/netdev-dpdk.c
> index 4bf0ca9..5216b74 100644
> --- a/lib/netdev-dpdk.c
> +++ b/lib/netdev-dpdk.c
> @@ -4570,10 +4570,10 @@ netdev_dpdk_add_rte_flow_offload(struct netdev *netdev,
>      /* Eth */
>      struct rte_flow_item_eth eth_spec;
>      struct rte_flow_item_eth eth_mask;
> -    memset(&eth_spec, 0, sizeof(eth_spec));
> -    memset(&eth_mask, 0, sizeof(eth_mask));
>      if (!eth_addr_is_zero(match->wc.masks.dl_src) ||
>          !eth_addr_is_zero(match->wc.masks.dl_dst)) {
> +        memset(&eth_spec, 0, sizeof(eth_spec));
> +        memset(&eth_mask, 0, sizeof(eth_mask));
>          rte_memcpy(&eth_spec.dst, &match->flow.dl_dst, sizeof(eth_spec.dst));
>          rte_memcpy(&eth_spec.src, &match->flow.dl_src, sizeof(eth_spec.src));
>          eth_spec.type = match->flow.dl_type;
> @@ -4600,9 +4600,9 @@ netdev_dpdk_add_rte_flow_offload(struct netdev *netdev,
>      /* VLAN */
>      struct rte_flow_item_vlan vlan_spec;
>      struct rte_flow_item_vlan vlan_mask;
> -    memset(&vlan_spec, 0, sizeof(vlan_spec));
> -    memset(&vlan_mask, 0, sizeof(vlan_mask));
>      if (match->wc.masks.vlans[0].tci && match->flow.vlans[0].tci) {
> +        memset(&vlan_spec, 0, sizeof(vlan_spec));
> +        memset(&vlan_mask, 0, sizeof(vlan_mask));
>          vlan_spec.tci  = match->flow.vlans[0].tci & ~htons(VLAN_CFI);
>          vlan_mask.tci  = match->wc.masks.vlans[0].tci & ~htons(VLAN_CFI);
>  
> @@ -4617,9 +4617,9 @@ netdev_dpdk_add_rte_flow_offload(struct netdev *netdev,
>      uint8_t proto = 0;
>      struct rte_flow_item_ipv4 ipv4_spec;
>      struct rte_flow_item_ipv4 ipv4_mask;
> -    memset(&ipv4_spec, 0, sizeof(ipv4_spec));
> -    memset(&ipv4_mask, 0, sizeof(ipv4_mask));
>      if (match->flow.dl_type == htons(ETH_TYPE_IP)) {
> +        memset(&ipv4_spec, 0, sizeof(ipv4_spec));
> +        memset(&ipv4_mask, 0, sizeof(ipv4_mask));
>  
>          ipv4_spec.hdr.type_of_service = match->flow.nw_tos;
>          ipv4_spec.hdr.time_to_live    = match->flow.nw_ttl;
> @@ -4662,9 +4662,9 @@ netdev_dpdk_add_rte_flow_offload(struct netdev *netdev,
>  
>      struct rte_flow_item_tcp tcp_spec;
>      struct rte_flow_item_tcp tcp_mask;
> -    memset(&tcp_spec, 0, sizeof(tcp_spec));
> -    memset(&tcp_mask, 0, sizeof(tcp_mask));
>      if (proto == IPPROTO_TCP) {
> +        memset(&tcp_spec, 0, sizeof(tcp_spec));
> +        memset(&tcp_mask, 0, sizeof(tcp_mask));
>          tcp_spec.hdr.src_port  = match->flow.tp_src;
>          tcp_spec.hdr.dst_port  = match->flow.tp_dst;
>          tcp_spec.hdr.data_off  = ntohs(match->flow.tcp_flags) >> 8;
> @@ -4687,9 +4687,9 @@ netdev_dpdk_add_rte_flow_offload(struct netdev *netdev,
>  
>      struct rte_flow_item_udp udp_spec;
>      struct rte_flow_item_udp udp_mask;
> -    memset(&udp_spec, 0, sizeof(udp_spec));
> -    memset(&udp_mask, 0, sizeof(udp_mask));
>      if (proto == IPPROTO_UDP) {
> +        memset(&udp_spec, 0, sizeof(udp_spec));
> +        memset(&udp_mask, 0, sizeof(udp_mask));
>          udp_spec.hdr.src_port = match->flow.tp_src;
>          udp_spec.hdr.dst_port = match->flow.tp_dst;
>  
> @@ -4708,9 +4708,9 @@ netdev_dpdk_add_rte_flow_offload(struct netdev *netdev,
>  
>      struct rte_flow_item_sctp sctp_spec;
>      struct rte_flow_item_sctp sctp_mask;
> -    memset(&sctp_spec, 0, sizeof(sctp_spec));
> -    memset(&sctp_mask, 0, sizeof(sctp_mask));
>      if (proto == IPPROTO_SCTP) {
> +        memset(&sctp_spec, 0, sizeof(sctp_spec));
> +        memset(&sctp_mask, 0, sizeof(sctp_mask));
>          sctp_spec.hdr.src_port = match->flow.tp_src;
>          sctp_spec.hdr.dst_port = match->flow.tp_dst;
>  
> @@ -4729,9 +4729,9 @@ netdev_dpdk_add_rte_flow_offload(struct netdev *netdev,
>  
>      struct rte_flow_item_icmp icmp_spec;
>      struct rte_flow_item_icmp icmp_mask;
> -    memset(&icmp_spec, 0, sizeof(icmp_spec));
> -    memset(&icmp_mask, 0, sizeof(icmp_mask));
>      if (proto == IPPROTO_ICMP) {
> +        memset(&icmp_spec, 0, sizeof(icmp_spec));
> +        memset(&icmp_mask, 0, sizeof(icmp_mask));
>          icmp_spec.hdr.icmp_type = (uint8_t)ntohs(match->flow.tp_src);
>          icmp_spec.hdr.icmp_code = (uint8_t)ntohs(match->flow.tp_dst);
>  
> 


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