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Commit 62f64aed authored by Alexei Starovoitov's avatar Alexei Starovoitov Committed by David S. Miller
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pktgen: introduce xmit_mode '<start_xmit|netif_receive>' 



Introduce xmit_mode 'netif_receive' for pktgen which generates the
packets using familiar pktgen commands, but feeds them into
netif_receive_skb() instead of ndo_start_xmit().

Default mode is called 'start_xmit'.

It is designed to test netif_receive_skb and ingress qdisc
performace only. Make sure to understand how it works before
using it for other rx benchmarking.

Sample script 'pktgen.sh':
\#!/bin/bash
function pgset() {
  local result

  echo $1 > $PGDEV

  result=`cat $PGDEV | fgrep "Result: OK:"`
  if [ "$result" = "" ]; then
    cat $PGDEV | fgrep Result:
  fi
}

[ -z "$1" ] && echo "Usage: $0 DEV" && exit 1
ETH=$1

PGDEV=/proc/net/pktgen/kpktgend_0
pgset "rem_device_all"
pgset "add_device $ETH"

PGDEV=/proc/net/pktgen/$ETH
pgset "xmit_mode netif_receive"
pgset "pkt_size 60"
pgset "dst 198.18.0.1"
pgset "dst_mac 90:e2:ba:ff:ff:ff"
pgset "count 10000000"
pgset "burst 32"

PGDEV=/proc/net/pktgen/pgctrl
echo "Running... ctrl^C to stop"
pgset "start"
echo "Done"
cat /proc/net/pktgen/$ETH

Usage:
$ sudo ./pktgen.sh eth2
...
Result: OK: 232376(c232372+d3) usec, 10000000 (60byte,0frags)
  43033682pps 20656Mb/sec (20656167360bps) errors: 10000000

Raw netif_receive_skb speed should be ~43 million packet
per second on 3.7Ghz x86 and 'perf report' should look like:
  37.69%  kpktgend_0   [kernel.vmlinux]  [k] __netif_receive_skb_core
  25.81%  kpktgend_0   [kernel.vmlinux]  [k] kfree_skb
   7.22%  kpktgend_0   [kernel.vmlinux]  [k] ip_rcv
   5.68%  kpktgend_0   [pktgen]          [k] pktgen_thread_worker

If fib_table_lookup is seen on top, it means skb was processed
by the stack. To benchmark netif_receive_skb only make sure
that 'dst_mac' of your pktgen script is different from
receiving device mac and it will be dropped by ip_rcv

Signed-off-by: default avatarAlexei Starovoitov <ast@plumgrid.com>
Signed-off-by: default avatarJesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent f1f00d8f

Documentation/networking/pktgen.txt

+7 −0
Original line number Diff line number Diff line
@@ -193,6 +193,10 @@ Examples: 
 pgset "rate 300M"        set rate to 300 Mb/s

 pgset "ratep 1000000"    set rate to 1Mpps



 pgset "xmit_mode netif_receive"  RX inject into stack netif_receive_skb()

				  Works with "burst" but not with "clone_skb".

				  Default xmit_mode is "start_xmit".



Sample scripts

==============
@@ -310,6 +314,9 @@ flowlen 
rate

ratep



xmit_mode <start_xmit|netif_receive>





References:

ftp://robur.slu.se/pub/Linux/net-development/pktgen-testing/

ftp://robur.slu.se/pub/Linux/net-development/pktgen-testing/examples/

net/core/pktgen.c

+77 −5
Original line number Diff line number Diff line
@@ -210,6 +210,10 @@ 
#define T_REMDEVALL   (1<<2)	/* Remove all devs */

#define T_REMDEV      (1<<3)	/* Remove one dev */



/* Xmit modes */

#define M_START_XMIT		0	/* Default normal TX */

#define M_NETIF_RECEIVE 	1	/* Inject packets into stack */



/* If lock -- protects updating of if_list */

#define   if_lock(t)           spin_lock(&(t->if_lock));

#define   if_unlock(t)           spin_unlock(&(t->if_lock));
@@ -251,13 +255,14 @@ struct pktgen_dev { 
	 * we will do a random selection from within the range.

	 */

	__u32 flags;

	int removal_mark;	/* non-zero => the device is marked for

				 * removal by worker thread */



	int xmit_mode;

	int min_pkt_size;

	int max_pkt_size;

	int pkt_overhead;	/* overhead for MPLS, VLANs, IPSEC etc */

	int nfrags;

	int removal_mark;	/* non-zero => the device is marked for

				 * removal by worker thread */



	struct page *page;

	u64 delay;		/* nano-seconds */
@@ -620,6 +625,9 @@ static int pktgen_if_show(struct seq_file *seq, void *v) 
	if (pkt_dev->node >= 0)

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



	if (pkt_dev->xmit_mode == M_NETIF_RECEIVE)

		seq_puts(seq, "     xmit_mode: netif_receive\n");



	seq_puts(seq, "     Flags: ");



	if (pkt_dev->flags & F_IPV6)
@@ -1081,7 +1089,8 @@ static ssize_t pktgen_if_write(struct file *file, 
		if (len < 0)

			return len;

		if ((value > 0) &&

		    (!(pkt_dev->odev->priv_flags & IFF_TX_SKB_SHARING)))

		    ((pkt_dev->xmit_mode == M_NETIF_RECEIVE) ||

		     !(pkt_dev->odev->priv_flags & IFF_TX_SKB_SHARING)))

			return -ENOTSUPP;

		i += len;

		pkt_dev->clone_skb = value;
@@ -1134,7 +1143,7 @@ static ssize_t pktgen_if_write(struct file *file, 
			return len;



		i += len;

		if ((value > 1) &&

		if ((value > 1) && (pkt_dev->xmit_mode == M_START_XMIT) &&

		    (!(pkt_dev->odev->priv_flags & IFF_TX_SKB_SHARING)))

			return -ENOTSUPP;

		pkt_dev->burst = value < 1 ? 1 : value;
@@ -1160,6 +1169,35 @@ static ssize_t pktgen_if_write(struct file *file, 
			sprintf(pg_result, "ERROR: node not possible");

		return count;

	}

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

		char f[32];



		memset(f, 0, 32);

		len = strn_len(&user_buffer[i], sizeof(f) - 1);

		if (len < 0)

			return len;



		if (copy_from_user(f, &user_buffer[i], len))

			return -EFAULT;

		i += len;



		if (strcmp(f, "start_xmit") == 0) {

			pkt_dev->xmit_mode = M_START_XMIT;

		} else if (strcmp(f, "netif_receive") == 0) {

			/* clone_skb set earlier, not supported in this mode */

			if (pkt_dev->clone_skb > 0)

				return -ENOTSUPP;



			pkt_dev->xmit_mode = M_NETIF_RECEIVE;

		} else {

			sprintf(pg_result,

				"xmit_mode -:%s:- unknown\nAvailable modes: %s",

				f, "start_xmit, netif_receive\n");

			return count;

		}

		sprintf(pg_result, "OK: xmit_mode=%s", f);

		return count;

	}

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

		char f[32];

		memset(f, 0, 32);
@@ -3320,6 +3358,7 @@ 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;

	struct sk_buff *skb;

	int ret;



	/* If device is offline, then don't send */
@@ -3357,6 +3396,38 @@ static void pktgen_xmit(struct pktgen_dev *pkt_dev) 
	if (pkt_dev->delay && pkt_dev->last_ok)

		spin(pkt_dev, pkt_dev->next_tx);



	if (pkt_dev->xmit_mode == M_NETIF_RECEIVE) {

		skb = pkt_dev->skb;

		skb->protocol = eth_type_trans(skb, skb->dev);

		atomic_add(burst, &skb->users);

		local_bh_disable();

		do {

			ret = netif_receive_skb(skb);

			if (ret == NET_RX_DROP)

				pkt_dev->errors++;

			pkt_dev->sofar++;

			pkt_dev->seq_num++;

			if (atomic_read(&skb->users) != burst) {

				/* skb was queued by rps/rfs or taps,

				 * so cannot reuse this skb

				 */

				atomic_sub(burst - 1, &skb->users);

				/* get out of the loop and wait

				 * until skb is consumed

				 */

				pkt_dev->last_ok = 1;

				break;

			}

			/* skb was 'freed' by stack, so clean few

			 * bits and reuse it

			 */

#ifdef CONFIG_NET_CLS_ACT

			skb->tc_verd = 0; /* reset reclass/redir ttl */

#endif

		} while (--burst > 0);

		goto out; /* Skips xmit_mode M_START_XMIT */

	}



	txq = skb_get_tx_queue(odev, pkt_dev->skb);



	local_bh_disable();
@@ -3404,6 +3475,7 @@ static void pktgen_xmit(struct pktgen_dev *pkt_dev) 
unlock:

	HARD_TX_UNLOCK(odev, txq);



out:

	local_bh_enable();



	/* If pkt_dev->count is zero, then run forever */