Commit 38b2cf29 authored by Alexei Starovoitov's avatar Alexei Starovoitov Committed by David S. Miller
Browse files

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: default avatarAlexei Starovoitov <ast@plumgrid.com>
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Acked-by: default avatarJesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 775dd692

Documentation/networking/pktgen.txt

+3 −0
Original line number Diff line number Diff line
@@ -99,6 +99,9 @@ Examples: 


 pgset "clone_skb 1"     sets the number of copies of the same packet

 pgset "clone_skb 0"     use single SKB for all transmits

 pgset "burst 8"         uses xmit_more API to queue 8 copies of the same

                         packet and update HW tx queue tail pointer once.

                         "burst 1" is the default

 pgset "pkt_size 9014"   sets packet size to 9014

 pgset "frags 5"         packet will consist of 5 fragments

 pgset "count 200000"    sets number of packets to send, set to zero

net/core/pktgen.c

+24 −2
Original line number Diff line number Diff line
@@ -387,6 +387,7 @@ struct pktgen_dev { 
	u16 queue_map_min;

	u16 queue_map_max;

	__u32 skb_priority;	/* skb priority field */

	unsigned int burst;	/* number of duplicated packets to burst */

	int node;               /* Memory node */



#ifdef CONFIG_XFRM
@@ -613,6 +614,9 @@ static int pktgen_if_show(struct seq_file *seq, void *v) 
	if (pkt_dev->traffic_class)

		seq_printf(seq, "     traffic_class: 0x%02x\n", pkt_dev->traffic_class);



	if (pkt_dev->burst > 1)

		seq_printf(seq, "     burst: %d\n", pkt_dev->burst);



	if (pkt_dev->node >= 0)

		seq_printf(seq, "     node: %d\n", pkt_dev->node);
@@ -1124,6 +1128,16 @@ static ssize_t pktgen_if_write(struct file *file, 
			pkt_dev->dst_mac_count);

		return count;

	}

	if (!strcmp(name, "burst")) {

		len = num_arg(&user_buffer[i], 10, &value);

		if (len < 0)

			return len;



		i += len;

		pkt_dev->burst = value < 1 ? 1 : value;

		sprintf(pg_result, "OK: burst=%d", pkt_dev->burst);

		return count;

	}

	if (!strcmp(name, "node")) {

		len = num_arg(&user_buffer[i], 10, &value);

		if (len < 0)
@@ -3297,6 +3311,7 @@ static void pktgen_wait_for_skb(struct pktgen_dev *pkt_dev) 


static void pktgen_xmit(struct pktgen_dev *pkt_dev)

{

	unsigned int burst = ACCESS_ONCE(pkt_dev->burst);

	struct net_device *odev = pkt_dev->odev;

	struct netdev_queue *txq;

	int ret;
@@ -3347,8 +3362,10 @@ static void pktgen_xmit(struct pktgen_dev *pkt_dev) 
		pkt_dev->last_ok = 0;

		goto unlock;

	}

	atomic_inc(&(pkt_dev->skb->users));

	ret = netdev_start_xmit(pkt_dev->skb, odev, txq, false);

	atomic_add(burst, &pkt_dev->skb->users);



xmit_more:

	ret = netdev_start_xmit(pkt_dev->skb, odev, txq, --burst > 0);



	switch (ret) {

	case NETDEV_TX_OK:
@@ -3356,6 +3373,8 @@ static void pktgen_xmit(struct pktgen_dev *pkt_dev) 
		pkt_dev->sofar++;

		pkt_dev->seq_num++;

		pkt_dev->tx_bytes += pkt_dev->last_pkt_size;

		if (burst > 0 && !netif_xmit_frozen_or_drv_stopped(txq))

			goto xmit_more;

		break;

	case NET_XMIT_DROP:

	case NET_XMIT_CN:
@@ -3374,6 +3393,8 @@ static void pktgen_xmit(struct pktgen_dev *pkt_dev) 
		atomic_dec(&(pkt_dev->skb->users));

		pkt_dev->last_ok = 0;

	}

	if (unlikely(burst))

		atomic_sub(burst, &pkt_dev->skb->users);

unlock:

	HARD_TX_UNLOCK(odev, txq);
@@ -3572,6 +3593,7 @@ static int pktgen_add_device(struct pktgen_thread *t, const char *ifname) 
	pkt_dev->svlan_p = 0;

	pkt_dev->svlan_cfi = 0;

	pkt_dev->svlan_id = 0xffff;

	pkt_dev->burst = 1;

	pkt_dev->node = -1;



	err = pktgen_setup_dev(t->net, pkt_dev, ifname);

CRA Git | Maintained and supported by SUSTech CRA and CCSE