[ovs-dev] [RFC PATCH v2] net-dpdk: Introducing TX TCP/UDP HW checksum offload support for DPDK pnic

Gao Zhenyu sysugaozhenyu at gmail.com
Thu Jul 20 14:02:53 UTC 2017


 the setup like:

     qperf client
+---------+
|   VM    |
+---------+
     |
     |                          qperf server
+--------------+              +------------+
| vswitch+dpdk |              | bare-metal |
+--------------+              +------------+
       |                            |
       |                            |
      pNic---------PhysicalSwitch----



Here is some performance testing result base on latest ovs. For udp jumbo
packet,VM always comput it by itself because of mtu(1500) and IP fragment.
So it doesn't show too much improvment on it.
The result of patch-SW-CKSUM means it skips netdev_prepare_tx_csum and
execute "ethtool -K eth0 tx off" in VM side.
So it consumes VM's cksum function for tcp/udp packets.

qperf -t 60 -oo msg_size:1:64K:*2  10.100.85.247 tcp_bw tcp_lat udp_bw
udp_lat
without-patch(cksum in VM)      patch-SW-CKSUM(cksum in VM)
patch-HW-CKSUM
tcp_bw:
    bw  =  1.95 MB/sec             1.93 MB/sec                  1.9 MB/sec
tcp_bw:
    bw  =  3.93 MB/sec             3.83 MB/sec                  3.83 MB/sec
tcp_bw:
    bw  =  8.04 MB/sec             7.81 MB/sec                  7.71 MB/sec
tcp_bw:
    bw  =  15.3 MB/sec             14.7 MB/sec                  14.5 MB/sec
tcp_bw:
    bw  =  29.6 MB/sec             27.4 MB/sec                  27 MB/sec
tcp_bw:
     bw  =  54.5 MB/sec            50.7 MB/sec                  50.5 MB/sec
tcp_bw:
    bw  =  92.9 MB/sec             83.7 MB/sec                  82.6 MB/sec
tcp_bw:
    bw  =  147 MB/sec              144 MB/sec                   146 MB/sec
tcp_bw:
    bw  =  194 MB/sec              203 MB/sec                   211 MB/sec
tcp_bw:
    bw  =  255 MB/sec              253 MB/sec                   257 MB/sec
tcp_bw:
     bw  =  303 MB/sec             294 MB/sec                   301 MB/sec
tcp_bw:
    bw  =  337 MB/sec              354 MB/sec                   379 MB/sec
tcp_bw:
    bw  =  402 MB/sec              506 MB/sec                   556 MB/sec
tcp_bw:
    bw  =  444 MB/sec              698 MB/sec                   800 MB/sec
tcp_bw:
    bw  =  468 MB/sec              866 MB/sec                   1.03 GB/sec
tcp_bw:
     bw  =  477 MB/sec             985 MB/sec                   1.11 GB/sec
tcp_bw:
    bw  =  517 MB/sec              1.09 GB/sec                  1.17 GB/sec
tcp_lat:
    latency  =  28.8 us            29.4 us                      29.8 us
tcp_lat:
    latency  =  28.5 us            29.3 us                      29.6 us
tcp_lat:
    latency  =  28.7 us            29.3 us                      29.5 us
tcp_lat:
     latency  =  28.6 us           29.3 us                      29.5 us
tcp_lat:
    latency  =  28.6 us            29.3 us                      29.7 us
tcp_lat:
    latency  =  28.6 us            29.5 us                      29.9 us
tcp_lat:
    latency  =  29 us              29.8 us                      30.4 us
tcp_lat:
    latency  =  29.2 us            30.3 us                      30.2 us
tcp_lat:
     latency  =  30.4 us           30.9 us                      31 us
tcp_lat:
    latency  =  43.6 us            32.2 us                      32.3 us
tcp_lat:
    latency  =  47.8 us            34.3 us                      34.7 us
tcp_lat:
    latency  =  43.3 us            44.2 us                      44.1 us
tcp_lat:
    latency  =  47.4 us            48 us                        47.1 us
tcp_lat:
     latency  =  76.9 us           75.9 us                      76.8 us
tcp_lat:
    latency  =  83.5 us            83.1 us                      84.1 us
tcp_lat:
    latency  =  134 us             94.6 us                      96.1 us
tcp_lat:
    latency  =  184 us             203 us                       196 us
udp_bw:
    send_bw  =  399 KB/sec         send_bw  =  397 KB/sec       send_bw  =
405 KB/sec
    recv_bw  =  392 KB/sec         recv_bw  =  389 KB/sec       recv_bw  =
398 KB/sec
udp_bw:
     send_bw  =  812 KB/sec        send_bw  =  788 KB/sec       send_bw  =
812 KB/sec
    recv_bw  =  800 KB/sec         recv_bw  =  773 KB/sec       recv_bw  =
800 KB/sec
udp_bw:
    send_bw  =  1.64 MB/sec        send_bw  =  1.59 MB/sec      send_bw  =
1.61 MB/sec
    recv_bw  =  1.63 MB/sec        recv_bw  =  1.53 MB/sec      recv_bw  =
1.58 MB/sec
udp_bw:
    send_bw  =  3.25 MB/sec        send_bw  =  3.16 MB/sec      send_bw  =
3.24 MB/sec
    recv_bw  =  3.23 MB/sec        recv_bw  =  3.05 MB/sec      recv_bw  =
3.13 MB/sec
udp_bw:
    send_bw  =  6.59 MB/sec        send_bw  =  6.35 MB/sec      send_bw  =
6.43 MB/sec
    recv_bw  =   6.5 MB/sec        recv_bw  =  6.22 MB/sec      recv_bw  =
6.22 MB/sec
udp_bw:
    send_bw  =    13 MB/sec        send_bw  =  12.5 MB/sec      send_bw  =
12.8 MB/sec
    recv_bw  =  12.9 MB/sec        recv_bw  =  12.3 MB/sec      recv_bw  =
12.4 MB/sec
udp_bw:
     send_bw  =  26.1 MB/sec       send_bw  =  25.3 MB/sec      send_bw  =
25.8 MB/sec
    recv_bw  =  25.5 MB/sec        recv_bw  =    25 MB/sec      recv_bw  =
25.1 MB/sec
udp_bw:
    send_bw  =  51.3 MB/sec        send_bw  =  50.5 MB/sec      send_bw  =
51.7 MB/sec
    recv_bw  =  50.8 MB/sec        recv_bw  =  49.9 MB/sec      recv_bw  =
51.1 MB/sec
udp_bw:
    send_bw  =   104 MB/sec        send_bw  =   100 MB/sec      send_bw
=   102 MB/sec
    recv_bw  =  99.3 MB/sec        recv_bw  =  91.3 MB/sec      recv_bw  =
99.1 MB/sec
udp_bw:
    send_bw  =  206 MB/sec         send_bw  =  194 MB/sec       send_bw  =
206 MB/sec
    recv_bw  =  200 MB/sec         recv_bw  =  164 MB/sec       recv_bw  =
199 MB/sec
udp_bw:
    send_bw  =  403 MB/sec         send_bw  =  385 MB/sec       send_bw  =
402 MB/sec
    recv_bw  =  390 MB/sec         recv_bw  =  351 MB/sec       recv_bw  =
389 MB/sec
udp_bw:
     send_bw  =  554 MB/sec        send_bw  =  550 MB/sec       send_bw  =
539 MB/sec
    recv_bw  =  367 MB/sec         recv_bw  =  365 MB/sec       recv_bw  =
393 MB/sec
udp_bw:
    send_bw  =  868 MB/sec         send_bw  =  835 MB/sec       send_bw  =
854 MB/sec
    recv_bw  =  576 MB/sec         recv_bw  =  569 MB/sec       recv_bw  =
652 MB/sec
udp_bw:
    send_bw  =  1.09 GB/sec        send_bw  =  1.08 GB/sec      send_bw  =
1.06 GB/sec
    recv_bw  =   772 MB/sec        recv_bw  =   770 MB/sec      recv_bw
=   569 MB/sec
udp_bw:
    send_bw  =  1.22 GB/sec        send_bw  =  1.22 GB/sec      send_bw  =
1.19 GB/sec
    recv_bw  =   676 MB/sec        recv_bw  =   700 MB/sec      recv_bw
=   767 MB/sec
udp_bw:
    send_bw  =  1.29 GB/sec        send_bw  =  1.28 GB/sec      send_bw  =
1.29 GB/sec
    recv_bw  =   666 MB/sec        recv_bw  =   795 MB/sec      recv_bw
=   671 MB/sec
udp_bw:
     send_bw  =  0 bytes/sec       send_bw  =  0 bytes/sec      send_bw  =
0 bytes/sec
    recv_bw  =  0 bytes/sec        recv_bw  =  0 bytes/sec      recv_bw  =
0 bytes/sec
udp_lat:
    latency  =  25.7 us            latency  =  25.8 us          latency  =
25.9 us
udp_lat:
    latency  =  26 us              latency  =  25.9 us          latency  =
25.9 us
udp_lat:
    latency  =  25.9 us            latency  =  25.8 us          latency  =
26 us
udp_lat:
    latency  =  25.8 us            latency  =  25.8 us          latency  =
26 us
udp_lat:
     latency  =  25.9 us           latency  =  25.9 us          latency  =
26.1 us
udp_lat:
    latency  =  26 us              latency  =  25.8 us          latency  =
26.1 us
udp_lat:
    latency  =  26.2 us            latency  =  25.9 us          latency  =
26.3 us
udp_lat:
    latency  =  26.7 us            latency  =  26.5 us          latency  =
27 us
udp_lat:
    latency  =  27.3 us            latency  =  27.3 us          latency  =
27.7 us
udp_lat:
     latency  =  28.3 us           latency  =  28.1 us          latency  =
28.9 us
udp_lat:
    latency  =  30 us              latency  =  29.7 us          latency  =
30.4 us
udp_lat:
    latency  =  41.3 us            latency  =  41.3 us          latency  =
41.3 us
udp_lat:
    latency  =  41.6 us            latency  =  41.6 us          latency  =
41.6 us
udp_lat:
    latency  =  64.2 us            latency  =  64.2 us          latency  =
64.4 us
udp_lat:
     latency  =  73.2 us           latency  =  86.9 us          latency  =
72.3 us
udp_lat:
    latency  =  120 us             latency  =  119 us           latency  =
117 us
udp_lat:
    latency  =  0 ns               latency  =  0 ns             latency  =
0 ns

2017-07-20 21:54 GMT+08:00 Zhenyu Gao <sysugaozhenyu at gmail.com>:

> This patch introduce TX tcp/udp-checksum offload support for DPDK pnic.
> The feature is disabled by default and can be enabled by setting
> tx-checksum-offload, which like:
> ovs-vsctl set Interface dpdk-eth3 \
>  options:tx-checksum-offload=true
>
> Signed-off-by: Zhenyu Gao <sysugaozhenyu at gmail.com>
> ---
>  lib/netdev-dpdk.c    | 144 ++++++++++++++++++++++++++++++
> +++++++++++++++++++--
>  vswitchd/vswitch.xml |  15 ++++++
>  2 files changed, 156 insertions(+), 3 deletions(-)
>
> diff --git a/lib/netdev-dpdk.c b/lib/netdev-dpdk.c
> index ea17b97..489688f 100644
> --- a/lib/netdev-dpdk.c
> +++ b/lib/netdev-dpdk.c
> @@ -32,6 +32,7 @@
>  #include <rte_mbuf.h>
>  #include <rte_meter.h>
>  #include <rte_virtio_net.h>
> +#include <rte_ip.h>
>
>  #include "dirs.h"
>  #include "dp-packet.h"
> @@ -328,6 +329,7 @@ struct ingress_policer {
>
>  enum dpdk_hw_ol_features {
>      NETDEV_RX_CHECKSUM_OFFLOAD = 1 << 0,
> +    NETDEV_TX_CHECKSUM_OFFLOAD = 1 << 1,
>  };
>
>  struct netdev_dpdk {
> @@ -649,6 +651,8 @@ dpdk_eth_dev_queue_setup(struct netdev_dpdk *dev, int
> n_rxq, int n_txq)
>      int diag = 0;
>      int i;
>      struct rte_eth_conf conf = port_conf;
> +    struct rte_eth_txconf *txconf;
> +    struct rte_eth_dev_info dev_info;
>
>      if (dev->mtu > ETHER_MTU) {
>          conf.rxmode.jumbo_frame = 1;
> @@ -676,9 +680,16 @@ dpdk_eth_dev_queue_setup(struct netdev_dpdk *dev,
> int n_rxq, int n_txq)
>              break;
>          }
>
> +        rte_eth_dev_info_get(dev->port_id, &dev_info);
> +        txconf = &dev_info.default_txconf;
> +        if (dev->hw_ol_features & NETDEV_TX_CHECKSUM_OFFLOAD) {
> +            /*Enable tx offload feature on pnic*/
> +            txconf->txq_flags = 0;
> +        }
> +
>          for (i = 0; i < n_txq; i++) {
>              diag = rte_eth_tx_queue_setup(dev->port_id, i, dev->txq_size,
> -                                          dev->socket_id, NULL);
> +                                          dev->socket_id, txconf);
>              if (diag) {
>                  VLOG_INFO("Interface %s txq(%d) setup error: %s",
>                            dev->up.name, i, rte_strerror(-diag));
> @@ -719,6 +730,29 @@ dpdk_eth_dev_queue_setup(struct netdev_dpdk *dev,
> int n_rxq, int n_txq)
>  }
>
>  static void
> +dpdk_eth_checksum_offload_configure(struct netdev_dpdk *dev)
> +    OVS_REQUIRES(dev->mutex)
> +{
> +    struct rte_eth_dev_info info;
> +    bool tx_csum_ol_flag = false;
> +    uint32_t tx_chksm_offload_capa = DEV_TX_OFFLOAD_UDP_CKSUM |
> +                                     DEV_TX_OFFLOAD_TCP_CKSUM;
> +
> +    rte_eth_dev_info_get(dev->port_id, &info);
> +    tx_csum_ol_flag = (dev->hw_ol_features & NETDEV_TX_CHECKSUM_OFFLOAD)
> != 0;
> +
> +    if (tx_csum_ol_flag &&
> +        (info.tx_offload_capa & tx_chksm_offload_capa) !=
> +            tx_chksm_offload_capa) {
> +        VLOG_WARN_ONCE("Tx checksum offload is not supported on device
> %"PRIu8,
> +                       dev->port_id);
> +        dev->hw_ol_features &= ~NETDEV_TX_CHECKSUM_OFFLOAD;
> +    } else {
> +        netdev_request_reconfigure(&dev->up);
> +    }
> +}
> +
> +static void
>  dpdk_eth_flow_ctrl_setup(struct netdev_dpdk *dev)
> OVS_REQUIRES(dev->mutex)
>  {
>      if (rte_eth_dev_flow_ctrl_set(dev->port_id, &dev->fc_conf)) {
> @@ -1108,6 +1142,11 @@ netdev_dpdk_get_config(const struct netdev *netdev,
> struct smap *args)
>          } else {
>              smap_add(args, "rx_csum_offload", "false");
>          }
> +        if (dev->hw_ol_features & NETDEV_TX_CHECKSUM_OFFLOAD) {
> +            smap_add(args, "tx_csum_offload", "true");
> +        } else {
> +            smap_add(args, "tx_csum_offload", "false");
> +        }
>      }
>      ovs_mutex_unlock(&dev->mutex);
>
> @@ -1198,6 +1237,9 @@ netdev_dpdk_set_config(struct netdev *netdev, const
> struct smap *args,
>          {RTE_FC_NONE,     RTE_FC_TX_PAUSE},
>          {RTE_FC_RX_PAUSE, RTE_FC_FULL    }
>      };
> +    bool tx_chksm_ofld;
> +    bool temp_tx_flag;
> +    bool change = false;
>      const char *new_devargs;
>      int err = 0;
>
> @@ -1279,6 +1321,19 @@ netdev_dpdk_set_config(struct netdev *netdev, const
> struct smap *args,
>          dpdk_eth_flow_ctrl_setup(dev);
>      }
>
> +    /* Tx checksum offload configuration */
> +    /* By default the Tx checksum offload is ON */
> +    tx_chksm_ofld = smap_get_bool(args, "tx-checksum-offload", true);
> +    temp_tx_flag = (dev->hw_ol_features & NETDEV_TX_CHECKSUM_OFFLOAD)
> +                        != 0;
> +    if (temp_tx_flag != tx_chksm_ofld) {
> +        dev->hw_ol_features ^= NETDEV_TX_CHECKSUM_OFFLOAD;
> +        change = true;
> +    }
> +
> +    if (change) {
> +        dpdk_eth_checksum_offload_configure(dev);
> +    }
>  out:
>      ovs_mutex_unlock(&dev->mutex);
>      ovs_mutex_unlock(&dpdk_mutex);
> @@ -1392,6 +1447,81 @@ netdev_dpdk_rxq_dealloc(struct netdev_rxq *rxq)
>      rte_free(rx);
>  }
>
> +static inline void
> +netdev_refill_l4_cksum(const char *data, struct dp_packet *pkt,
> +                       uint8_t l4_proto, bool is_ipv4)
> +{
> +    void *l3hdr = (void *)(data + pkt->l3_ofs);
> +    if (l4_proto == IPPROTO_TCP) {
> +        struct tcp_header *tcp_hdr = (struct tcp_header *)(data +
> pkt->l4_ofs);
> +
> +        pkt->mbuf.l2_len = pkt->l3_ofs;
> +        pkt->mbuf.l3_len = pkt->l4_ofs - pkt->l3_ofs;
> +        tcp_hdr->tcp_csum = 0;
> +        if (is_ipv4) {
> +            pkt->mbuf.ol_flags |= PKT_TX_TCP_CKSUM | PKT_TX_IPV4;
> +            tcp_hdr->tcp_csum = rte_ipv4_phdr_cksum(l3hdr,
> +                                                    pkt->mbuf.ol_flags);
> +        } else {
> +            pkt->mbuf.ol_flags |= PKT_TX_TCP_CKSUM | PKT_TX_IPV6;
> +            tcp_hdr->tcp_csum = rte_ipv6_phdr_cksum(l3hdr,
> +                                                    pkt->mbuf.ol_flags);
> +
> +        }
> +    } else if (l4_proto == IPPROTO_UDP) {
> +        struct udp_header *udp_hdr = (struct udp_header *)(data +
> pkt->l4_ofs);
> +        /* do not recalculate udp cksum if it was 0 */
> +        if (udp_hdr->udp_csum != 0) {
> +            pkt->mbuf.l2_len = pkt->l3_ofs;
> +            pkt->mbuf.l3_len = pkt->l4_ofs - pkt->l3_ofs;
> +            udp_hdr->udp_csum = 0;
> +            if (is_ipv4) {
> +                /*do not calculate udp cksum if it was a fragment IP*/
> +                if (IP_IS_FRAGMENT(((struct ipv4_hdr *)l3hdr)->
> +                                      fragment_offset)) {
> +                    return;
> +                }
> +                pkt->mbuf.ol_flags |= PKT_TX_UDP_CKSUM | PKT_TX_IPV4;
> +                udp_hdr->udp_csum = rte_ipv4_phdr_cksum(l3hdr,
> +
> pkt->mbuf.ol_flags);
> +            } else {
> +                pkt->mbuf.ol_flags |= PKT_TX_UDP_CKSUM | PKT_TX_IPV6;
> +                udp_hdr->udp_csum = rte_ipv6_phdr_cksum(l3hdr,
> +
> pkt->mbuf.ol_flags);
> +            }
> +        }
> +    }
> +}
> +
> +static inline void
> +netdev_prepare_tx_csum(struct dp_packet **pkts, int pkt_cnt)
> +{
> +    int i = 0;
> +
> +    for (i = 0; i < pkt_cnt; i++) {
> +        ovs_be16 dl_type;
> +        struct dp_packet *pkt = (struct dp_packet *)pkts[i];
> +        const char *data = dp_packet_data(pkt);
> +        void *l3hdr = (char *)(data + pkt->l3_ofs);
> +
> +        if (pkt->l4_ofs == UINT16_MAX || pkt->l3_ofs == UINT16_MAX) {
> +            continue;
> +        }
> +
> +        dl_type = *(ovs_be16 *)(data + pkt->l3_ofs - 2);
> +        if (dl_type == htons(ETH_TYPE_IP)) {
> +            netdev_refill_l4_cksum(data, pkt,
> +                                   ((struct ipv4_hdr
> *)l3hdr)->next_proto_id,
> +                                   true);
> +        } else if (dl_type == htons(ETH_TYPE_IPV6)) {
> +            netdev_refill_l4_cksum(data, pkt,
> +                                   ((struct ipv6_hdr *)l3hdr)->proto,
> +                                   false);
> +        }
> +
> +    }
> +}
> +
>  /* Tries to transmit 'pkts' to txq 'qid' of device 'dev'.  Takes
> ownership of
>   * 'pkts', even in case of failure.
>   *
> @@ -1780,6 +1910,11 @@ dpdk_do_tx_copy(struct netdev *netdev, int qid,
> struct dp_packet_batch *batch)
>          /* We have to do a copy for now */
>          memcpy(rte_pktmbuf_mtod(pkts[newcnt], void *),
>                 dp_packet_data(batch->packets[i]), size);
> +        if (batch->packets[i]->mbuf.ol_flags & PKT_TX_TCP_CKSUM) {
> +            pkts[newcnt]->l2_len = batch->packets[i]->mbuf.l2_len;
> +            pkts[newcnt]->l3_len = batch->packets[i]->mbuf.l3_len;
> +            pkts[newcnt]->ol_flags = batch->packets[i]->mbuf.ol_flags;
> +        }
>
>          rte_pktmbuf_data_len(pkts[newcnt]) = size;
>          rte_pktmbuf_pkt_len(pkts[newcnt]) = size;
> @@ -1833,6 +1968,10 @@ netdev_dpdk_send__(struct netdev_dpdk *dev, int qid,
>          return;
>      }
>
> +    if (dev->hw_ol_features & NETDEV_TX_CHECKSUM_OFFLOAD) {
> +        netdev_prepare_tx_csum(batch->packets, batch->count);
> +    }
> +
>      if (OVS_UNLIKELY(concurrent_txq)) {
>          qid = qid % dev->up.n_txq;
>          rte_spinlock_lock(&dev->tx_q[qid].tx_lock);
> @@ -2741,8 +2880,7 @@ netdev_dpdk_vhost_class_init(void)
>      if (ovsthread_once_start(&once)) {
>          rte_vhost_driver_callback_register(&virtio_net_device_ops);
>          rte_vhost_feature_disable(1ULL << VIRTIO_NET_F_HOST_TSO4
> -                                  | 1ULL << VIRTIO_NET_F_HOST_TSO6
> -                                  | 1ULL << VIRTIO_NET_F_CSUM);
> +                                  | 1ULL << VIRTIO_NET_F_HOST_TSO6);
>          ovs_thread_create("vhost_thread", start_vhost_loop, NULL);
>
>          ovsthread_once_done(&once);
> diff --git a/vswitchd/vswitch.xml b/vswitchd/vswitch.xml
> index 883ecd8..08e8d1d 100644
> --- a/vswitchd/vswitch.xml
> +++ b/vswitchd/vswitch.xml
> @@ -3480,6 +3480,21 @@
>        </column>
>      </group>
>
> +    <group title="TX Checksum Offload Configuration">
> +      <p>
> +        The checksum validation on the outgoing packets are
> +        performed on NIC using TX checksum offload feature. Implemented
> only
> +        for <code>dpdk
> +        </code>physical interfaces.
> +      </p>
> +
> +      <column name="options" key="tx-checksum-offload"
> +              type='{"type": "boolean"}'>
> +        Set to <code>false</code> to disble Tx checksum offloading on
> <code>
> +        dpdk</code>physical ports. By default, Tx checksum offload is
> enabled.
> +      </column>
> +    </group>
> +
>      <group title="Common Columns">
>        The overall purpose of these columns is described under <code>Common
>        Columns</code> at the beginning of this document.
> --
> 1.8.3.1
>
>


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