On Wed, Apr 13, 2016 at 7:42 AM, Sugesh Chandran
<sugesh.chand...@intel.com> wrote:
> Optimizing tunneling performance in userspace datapath by offloading the
> rx checksum validation on tunnel packets to the NIC when it is supported.
>
> This patch improves the bidirectional VxLAN tunneling performance by 8% and
> decapsulation performance by 24%. However it introduces 1% performance drop in
> PHY-PHY case due to the overhead of validating invalid checksum flag reported
> by NIC.
>
> Signed-off-by: Sugesh Chandran <sugesh.chand...@intel.com>
> ---
> lib/dpif-netdev.c | 40 ++++++++++++++++++++++++++++++++--------
> lib/netdev-dpdk.c | 39 +++++++++++++++++++++++++--------------
> lib/netdev-provider.h | 3 +++
> lib/netdev-vport.c | 25 +++++++++++++++----------
> lib/netdev.c | 1 +
> lib/netdev.h | 5 +++++
> lib/packets.h | 1 +
> 7 files changed, 82 insertions(+), 32 deletions(-)
>
> diff --git a/lib/dpif-netdev.c b/lib/dpif-netdev.c
> index 2870951..5de5c6a 100644
> --- a/lib/dpif-netdev.c
> +++ b/lib/dpif-netdev.c
> @@ -70,6 +70,7 @@
> #include "util.h"
>
> #include "openvswitch/vlog.h"
> +#include "netdev-provider.h"
>
> VLOG_DEFINE_THIS_MODULE(dpif_netdev);
>
> @@ -479,7 +480,8 @@ static void dp_netdev_execute_actions(struct
> dp_netdev_pmd_thread *pmd,
> const struct nlattr *actions,
> size_t actions_len);
> static void dp_netdev_input(struct dp_netdev_pmd_thread *,
> - struct dp_packet **, int cnt, odp_port_t
> port_no);
> + struct dp_packet **, int cnt,
> + struct dp_netdev_port *port);
> static void dp_netdev_recirculate(struct dp_netdev_pmd_thread *,
> struct dp_packet **, int cnt);
>
> @@ -2572,7 +2574,7 @@ dp_netdev_process_rxq_port(struct dp_netdev_pmd_thread
> *pmd,
> *recirc_depth_get() = 0;
>
> cycles_count_start(pmd);
> - dp_netdev_input(pmd, packets, cnt, port->port_no);
> + dp_netdev_input(pmd, packets, cnt, port);
> cycles_count_end(pmd, PMD_CYCLES_PROCESSING);
> } else if (error != EAGAIN && error != EOPNOTSUPP) {
> static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
> @@ -3394,6 +3396,20 @@ dp_netdev_queue_batches(struct dp_packet *pkt,
> packet_batch_update(batch, pkt, mf);
> }
>
> +static inline bool
> +is_checksum_valid(struct dp_packet *packet) {
> +#ifdef DPDK_NETDEV
> + if (packet->mbuf.ol_flags & (PKT_RX_IP_CKSUM_BAD |
> + PKT_RX_L4_CKSUM_BAD)) {
> + return 0;
> + }
> + packet->md.ol_flags = NETDEV_RX_CHECKSUM_OFFLOAD;
There is no need to define redundant flags for same information in
dp_packet. We can just access packet->mbuf members to check the
checksum flag.
> + return 1;
> +#else
> + return 0;
> +#endif
> +}
> +
> /* Try to process all ('cnt') the 'packets' using only the exact match cache
> * 'pmd->flow_cache'. If a flow is not found for a packet 'packets[i]', the
> * miniflow is copied into 'keys' and the packet pointer is moved at the
> @@ -3409,11 +3425,13 @@ static inline size_t
> emc_processing(struct dp_netdev_pmd_thread *pmd, struct dp_packet **packets,
> size_t cnt, struct netdev_flow_key *keys,
> struct packet_batch batches[], size_t *n_batches,
> - bool md_is_valid, odp_port_t port_no)
> + bool md_is_valid, struct dp_netdev_port *port)
> {
> struct emc_cache *flow_cache = &pmd->flow_cache;
> struct netdev_flow_key *key = &keys[0];
> size_t i, n_missed = 0, n_dropped = 0;
> + bool rx_cksm_ol_enable = port && (port->netdev->ol_flags &
> + NETDEV_RX_CHECKSUM_OFFLOAD);
>
> for (i = 0; i < cnt; i++) {
> struct dp_netdev_flow *flow;
> @@ -3425,6 +3443,12 @@ emc_processing(struct dp_netdev_pmd_thread *pmd,
> struct dp_packet **packets,
> continue;
> }
>
> + if (OVS_UNLIKELY(rx_cksm_ol_enable && !is_checksum_valid(packet))) {
Is checking for rx_cksum_ol_enable really required? No other netdev
implementation would initialize the packet ckecksum flags. So only
DPDK packets should return a invalid checksum here.
> + dp_packet_delete(packet);
> + n_dropped++;
> + continue;
> + }
> +
Calling checksum validation from datapath for all packets is odd. I am
not sure about the reasoning. I think we can validate the packet
checksum flags in tunnel code.
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