net: pktgen: packet bursting via skb->xmit_more
This patch demonstrates the effect of delaying update of HW tailptr. (based on earlier patch by Jesper) burst=1 is the default. It sends one packet with xmit_more=false burst=2 sends one packet with xmit_more=true and 2nd copy of the same packet with xmit_more=false burst=3 sends two copies of the same packet with xmit_more=true and 3rd copy with xmit_more=false Performance with ixgbe (usec 30): burst=1 tx:9.2 Mpps burst=2 tx:13.5 Mpps burst=3 tx:14.5 Mpps full 10G line rate Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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@ -99,6 +99,9 @@ Examples:
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pgset "clone_skb 1" sets the number of copies of the same packet
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pgset "clone_skb 0" use single SKB for all transmits
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pgset "burst 8" uses xmit_more API to queue 8 copies of the same
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packet and update HW tx queue tail pointer once.
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"burst 1" is the default
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pgset "pkt_size 9014" sets packet size to 9014
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pgset "frags 5" packet will consist of 5 fragments
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pgset "count 200000" sets number of packets to send, set to zero
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@ -387,6 +387,7 @@ struct pktgen_dev {
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u16 queue_map_min;
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u16 queue_map_max;
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__u32 skb_priority; /* skb priority field */
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unsigned int burst; /* number of duplicated packets to burst */
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int node; /* Memory node */
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#ifdef CONFIG_XFRM
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@ -613,6 +614,9 @@ static int pktgen_if_show(struct seq_file *seq, void *v)
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if (pkt_dev->traffic_class)
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seq_printf(seq, " traffic_class: 0x%02x\n", pkt_dev->traffic_class);
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if (pkt_dev->burst > 1)
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seq_printf(seq, " burst: %d\n", pkt_dev->burst);
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if (pkt_dev->node >= 0)
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seq_printf(seq, " node: %d\n", pkt_dev->node);
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@ -1124,6 +1128,16 @@ static ssize_t pktgen_if_write(struct file *file,
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pkt_dev->dst_mac_count);
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return count;
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}
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if (!strcmp(name, "burst")) {
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len = num_arg(&user_buffer[i], 10, &value);
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if (len < 0)
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return len;
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i += len;
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pkt_dev->burst = value < 1 ? 1 : value;
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sprintf(pg_result, "OK: burst=%d", pkt_dev->burst);
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return count;
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}
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if (!strcmp(name, "node")) {
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len = num_arg(&user_buffer[i], 10, &value);
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if (len < 0)
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@ -3297,6 +3311,7 @@ static void pktgen_wait_for_skb(struct pktgen_dev *pkt_dev)
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static void pktgen_xmit(struct pktgen_dev *pkt_dev)
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{
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unsigned int burst = ACCESS_ONCE(pkt_dev->burst);
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struct net_device *odev = pkt_dev->odev;
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struct netdev_queue *txq;
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int ret;
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@ -3347,8 +3362,10 @@ static void pktgen_xmit(struct pktgen_dev *pkt_dev)
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pkt_dev->last_ok = 0;
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goto unlock;
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}
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atomic_inc(&(pkt_dev->skb->users));
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ret = netdev_start_xmit(pkt_dev->skb, odev, txq, false);
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atomic_add(burst, &pkt_dev->skb->users);
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xmit_more:
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ret = netdev_start_xmit(pkt_dev->skb, odev, txq, --burst > 0);
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switch (ret) {
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case NETDEV_TX_OK:
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@ -3356,6 +3373,8 @@ static void pktgen_xmit(struct pktgen_dev *pkt_dev)
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pkt_dev->sofar++;
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pkt_dev->seq_num++;
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pkt_dev->tx_bytes += pkt_dev->last_pkt_size;
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if (burst > 0 && !netif_xmit_frozen_or_drv_stopped(txq))
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goto xmit_more;
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break;
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case NET_XMIT_DROP:
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case NET_XMIT_CN:
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@ -3374,6 +3393,8 @@ static void pktgen_xmit(struct pktgen_dev *pkt_dev)
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atomic_dec(&(pkt_dev->skb->users));
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pkt_dev->last_ok = 0;
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}
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if (unlikely(burst))
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atomic_sub(burst, &pkt_dev->skb->users);
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unlock:
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HARD_TX_UNLOCK(odev, txq);
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@ -3572,6 +3593,7 @@ static int pktgen_add_device(struct pktgen_thread *t, const char *ifname)
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pkt_dev->svlan_p = 0;
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pkt_dev->svlan_cfi = 0;
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pkt_dev->svlan_id = 0xffff;
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pkt_dev->burst = 1;
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pkt_dev->node = -1;
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err = pktgen_setup_dev(t->net, pkt_dev, ifname);
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