[PATCH 1/4] net/null: Tx optimizations

[Stephen Hemminger <stephen@networkplumber.org>]

All the null device does is call pktmbuf_free, can be marked lockless.
The statitistics need to use atomic for this.

Use rte_pktmbuf_free_bulk instead of a loop.
And pktmbuf_free handles multi-segment packets without problems.

There is no reason for eth_null_tx to check arguments,
no other tx_burst function does.

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
---
 drivers/net/null/#rte_eth_null.c# | 754 ++++++++++++++++++++++++++++++
 drivers/net/null/rte_eth_null.c   |  34 +-
 2 files changed, 766 insertions(+), 22 deletions(-)
 create mode 100644 drivers/net/null/#rte_eth_null.c#

diff --git a/drivers/net/null/#rte_eth_null.c# b/drivers/net/null/#rte_eth_null.c#
new file mode 100644
index 0000000000..9bac780e9e
--- /dev/null
+++ b/drivers/net/null/#rte_eth_null.c#
@@ -0,0 +1,754 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright (C) IGEL Co.,Ltd.
+ *  All rights reserved.
+ */
+
+#include <stdlib.h>
+
+#include <rte_mbuf.h>
+#include <ethdev_driver.h>
+#include <ethdev_vdev.h>
+#include <rte_malloc.h>
+#include <rte_memcpy.h>
+#include <bus_vdev_driver.h>
+#include <rte_kvargs.h>
+#include <rte_spinlock.h>
+
+#define ETH_NULL_PACKET_SIZE_ARG	"size"
+#define ETH_NULL_PACKET_COPY_ARG	"copy"
+#define ETH_NULL_PACKET_NO_RX_ARG	"no-rx"
+
+static unsigned int default_packet_size = 64;
+static unsigned int default_packet_copy;
+static unsigned int default_no_rx;
+
+static const char *valid_arguments[] = {
+	ETH_NULL_PACKET_SIZE_ARG,
+	ETH_NULL_PACKET_COPY_ARG,
+	ETH_NULL_PACKET_NO_RX_ARG,
+	NULL
+};
+
+struct pmd_internals;
+
+struct null_queue {
+	struct pmd_internals *internals;
+
+	struct rte_mempool *mb_pool;
+	void *dummy_packet;
+
+	uint64_t rx_pkts;
+	RTE_ATOMIC(uint64_t) tx_pkts;
+};
+
+struct pmd_options {
+	unsigned int packet_copy;
+	unsigned int packet_size;
+	unsigned int no_rx;
+};
+
+struct pmd_internals {
+	unsigned int packet_size;
+	unsigned int packet_copy;
+	unsigned int no_rx;
+	uint16_t port_id;
+
+	struct null_queue rx_null_queues[RTE_MAX_QUEUES_PER_PORT];
+	struct null_queue tx_null_queues[RTE_MAX_QUEUES_PER_PORT];
+
+	struct rte_ether_addr eth_addr;
+	/** Bit mask of RSS offloads, the bit offset also means flow type */
+	uint64_t flow_type_rss_offloads;
+
+	rte_spinlock_t rss_lock;
+
+	uint16_t reta_size;
+	struct rte_eth_rss_reta_entry64 reta_conf[RTE_ETH_RSS_RETA_SIZE_128 /
+			RTE_ETH_RETA_GROUP_SIZE];
+
+	uint8_t rss_key[40];                /**< 40-byte hash key. */
+};
+static struct rte_eth_link pmd_link = {
+	.link_speed = RTE_ETH_SPEED_NUM_10G,
+	.link_duplex = RTE_ETH_LINK_FULL_DUPLEX,
+	.link_status = RTE_ETH_LINK_DOWN,
+	.link_autoneg = RTE_ETH_LINK_FIXED,
+};
+
+RTE_LOG_REGISTER_DEFAULT(eth_null_logtype, NOTICE);
+#define RTE_LOGTYPE_ETH_NULL eth_null_logtype
+
+#define PMD_LOG(level, ...) \
+	RTE_LOG_LINE_PREFIX(level, ETH_NULL, "%s(): ", __func__, __VA_ARGS__)
+
+static uint16_t
+eth_null_rx(void *q, struct rte_mbuf **bufs, uint16_t nb_bufs)
+{
+	int i;
+	struct null_queue *h = q;
+	unsigned int packet_size;
+
+	packet_size = h->internals->packet_size;
+	if (rte_pktmbuf_alloc_bulk(h->mb_pool, bufs, nb_bufs) != 0)
+		return 0;
+
+	for (i = 0; i < nb_bufs; i++) {
+		bufs[i]->data_len = (uint16_t)packet_size;
+		bufs[i]->pkt_len = packet_size;
+		bufs[i]->port = h->internals->port_id;
+	}
+
+	h->rx_pkts += nb_bufs;
+	return nb_bufs;
+}
+
+static uint16_t
+eth_null_copy_rx(void *q, struct rte_mbuf **bufs, uint16_t nb_bufs)
+{
+	int i;
+	struct null_queue *h = q;
+	unsigned int packet_size;
+
+	packet_size = h->internals->packet_size;
+	if (rte_pktmbuf_alloc_bulk(h->mb_pool, bufs, nb_bufs) != 0)
+		return 0;
+
+	for (i = 0; i < nb_bufs; i++) {
+		rte_memcpy(rte_pktmbuf_mtod(bufs[i], void *), h->dummy_packet,
+					packet_size);
+		bufs[i]->data_len = (uint16_t)packet_size;
+		bufs[i]->pkt_len = packet_size;
+		bufs[i]->port = h->internals->port_id;
+	}
+
+	h->rx_pkts += nb_bufs;
+	return nb_bufs;
+}
+
+static uint16_t
+eth_null_no_rx(void *q __rte_unused, struct rte_mbuf **bufs __rte_unused,
+		uint16_t nb_bufs __rte_unused)
+{
+	return 0;
+}
+
+static uint16_t
+eth_null_tx(void *q, struct rte_mbuf **bufs, uint16_t nb_bufs)
+{
+	struct null_queue *h = q;
+
+	rte_pktmbuf_free_bulk(bufs, nb_bufs);
+	rte_atomic_fetch_add_explicit(&h->tx_pkts, nb_bufs, rte_memory_order_relaxed);
+
+	return nb_bufs;
+}
+
+static uint16_t
+eth_null_copy_tx(void *q, struct rte_mbuf **bufs, uint16_t nb_bufs)
+{
+	struct null_queue *h = q;
+	unsigned int i;
+
+	for (i = 0; i < nb_bufs; i++) {
+		struct rte_mbuf *m = bufs[i];
+		unsigned int len
+			= RTE_MIN(h->internals->packet_size, m->data_len);
+
+		rte_memcpy(h->dummy_packet, rte_pktmbuf_mtod(m, void *), len);
+		rte_pktmbuf_free(bufs[i]);
+	}
+
+	rte_atomic_fetch_add_explicit(&h->tx_pkts, nb_bufs, rte_memory_order_relaxed);
+	return nb_bufs;
+}
+
+static int
+eth_dev_configure(struct rte_eth_dev *dev __rte_unused)
+{
+	return 0;
+}
+
+static int
+eth_dev_start(struct rte_eth_dev *dev)
+{
+	uint16_t i;
+
+	if (dev == NULL)
+		return -EINVAL;
+
+	dev->data->dev_link.link_status = RTE_ETH_LINK_UP;
+
+	for (i = 0; i < dev->data->nb_rx_queues; i++)
+		dev->data->rx_queue_state[i] = RTE_ETH_QUEUE_STATE_STARTED;
+	for (i = 0; i < dev->data->nb_tx_queues; i++)
+		dev->data->tx_queue_state[i] = RTE_ETH_QUEUE_STATE_STARTED;
+
+	return 0;
+}
+
+static int
+eth_dev_stop(struct rte_eth_dev *dev)
+{
+	uint16_t i;
+
+	if (dev == NULL)
+		return 0;
+
+	dev->data->dev_link.link_status = RTE_ETH_LINK_DOWN;
+
+	for (i = 0; i < dev->data->nb_rx_queues; i++)
+		dev->data->rx_queue_state[i] = RTE_ETH_QUEUE_STATE_STOPPED;
+	for (i = 0; i < dev->data->nb_tx_queues; i++)
+		dev->data->tx_queue_state[i] = RTE_ETH_QUEUE_STATE_STOPPED;
+
+	return 0;
+}
+
+static int
+eth_rx_queue_setup(struct rte_eth_dev *dev, uint16_t rx_queue_id,
+		uint16_t nb_rx_desc __rte_unused,
+		unsigned int socket_id __rte_unused,
+		const struct rte_eth_rxconf *rx_conf __rte_unused,
+		struct rte_mempool *mb_pool)
+{
+	struct rte_mbuf *dummy_packet;
+	struct pmd_internals *internals;
+	unsigned int packet_size;
+
+	if ((dev == NULL) || (mb_pool == NULL))
+		return -EINVAL;
+
+	internals = dev->data->dev_private;
+
+	if (rx_queue_id >= dev->data->nb_rx_queues)
+		return -ENODEV;
+
+	packet_size = internals->packet_size;
+
+	internals->rx_null_queues[rx_queue_id].mb_pool = mb_pool;
+	dev->data->rx_queues[rx_queue_id] =
+		&internals->rx_null_queues[rx_queue_id];
+	dummy_packet = rte_zmalloc_socket(NULL,
+			packet_size, 0, dev->data->numa_node);
+	if (dummy_packet == NULL)
+		return -ENOMEM;
+
+	internals->rx_null_queues[rx_queue_id].internals = internals;
+	internals->rx_null_queues[rx_queue_id].dummy_packet = dummy_packet;
+
+	return 0;
+}
+
+static int
+eth_tx_queue_setup(struct rte_eth_dev *dev, uint16_t tx_queue_id,
+		uint16_t nb_tx_desc __rte_unused,
+		unsigned int socket_id __rte_unused,
+		const struct rte_eth_txconf *tx_conf __rte_unused)
+{
+	struct rte_mbuf *dummy_packet;
+	struct pmd_internals *internals;
+	unsigned int packet_size;
+
+	if (dev == NULL)
+		return -EINVAL;
+
+	internals = dev->data->dev_private;
+
+	if (tx_queue_id >= dev->data->nb_tx_queues)
+		return -ENODEV;
+
+	packet_size = internals->packet_size;
+
+	dev->data->tx_queues[tx_queue_id] =
+		&internals->tx_null_queues[tx_queue_id];
+	dummy_packet = rte_zmalloc_socket(NULL,
+			packet_size, 0, dev->data->numa_node);
+	if (dummy_packet == NULL)
+		return -ENOMEM;
+
+	internals->tx_null_queues[tx_queue_id].internals = internals;
+	internals->tx_null_queues[tx_queue_id].dummy_packet = dummy_packet;
+
+	return 0;
+}
+
+static int
+eth_mtu_set(struct rte_eth_dev *dev __rte_unused, uint16_t mtu __rte_unused)
+{
+	return 0;
+}
+
+static int
+eth_dev_info(struct rte_eth_dev *dev,
+		struct rte_eth_dev_info *dev_info)
+{
+	struct pmd_internals *internals;
+
+	if ((dev == NULL) || (dev_info == NULL))
+		return -EINVAL;
+
+	internals = dev->data->dev_private;
+	dev_info->max_mac_addrs = 1;
+	dev_info->max_rx_pktlen = (uint32_t)-1;
+	dev_info->max_rx_queues = RTE_DIM(internals->rx_null_queues);
+	dev_info->max_tx_queues = RTE_DIM(internals->tx_null_queues);
+	dev_info->min_rx_bufsize = 0;
+	dev_info->tx_offload_capa = RTE_ETH_TX_OFFLOAD_MULTI_SEGS | RTE_ETH_TX_OFFLOAD_MT_LOCKFREE;
+
+	dev_info->reta_size = internals->reta_size;
+	dev_info->flow_type_rss_offloads = internals->flow_type_rss_offloads;
+	dev_info->hash_key_size = sizeof(internals->rss_key);
+
+	return 0;
+}
+
+static int
+eth_stats_get(struct rte_eth_dev *dev, struct rte_eth_stats *stats)
+{
+	const struct pmd_internals *internal = dev->data->dev_private;
+	unsigned int i;
+	unsigned long rx_total = 0, tx_total = 0;
+
+	for (i = 0; i < dev->data->nb_rx_queues; i++) {
+		uint64_t pkts = internal->rx_null_queues[i].rx_pkts;
+
+		if (i < RTE_ETHDEV_QUEUE_STAT_CNTRS)
+			stats->q_ipackets[i] = pkts;
+
+		rx_total += pkts;
+	}
+
+	for (i = 0; i < dev->data->nb_tx_queues; i++) {
+		uint64_t pkts
+			= rte_atomic_load_explicit(&internal->tx_null_queues[i].tx_pkts,
+						   rte_memory_order_relaxed);
+
+		if (i < RTE_ETHDEV_QUEUE_STAT_CNTRS)
+			stats->q_opackets[i] = pkts;
+
+		tx_total += pkts;
+	}
+
+	stats->ipackets = rx_total;
+	stats->opackets = tx_total;
+
+	return 0;
+}
+
+static int
+eth_stats_reset(struct rte_eth_dev *dev)
+{
+	unsigned int i;
+	struct pmd_internals *internal;
+
+	if (dev == NULL)
+		return -EINVAL;
+
+	internal = dev->data->dev_private;
+	for (i = 0; i < RTE_DIM(internal->rx_null_queues); i++)
+		internal->rx_null_queues[i].rx_pkts = 0;
+	for (i = 0; i < RTE_DIM(internal->tx_null_queues); i++)
+		internal->tx_null_queues[i].tx_pkts = 0;
+
+	return 0;
+}
+
+static void
+eth_rx_queue_release(struct rte_eth_dev *dev, uint16_t qid)
+{
+	struct null_queue *nq = dev->data->rx_queues[qid];
+
+	if (nq == NULL)
+		return;
+
+	rte_free(nq->dummy_packet);
+}
+
+static void
+eth_tx_queue_release(struct rte_eth_dev *dev, uint16_t qid)
+{
+	struct null_queue *nq = dev->data->tx_queues[qid];
+
+	if (nq == NULL)
+		return;
+
+	rte_free(nq->dummy_packet);
+}
+
+static int
+eth_link_update(struct rte_eth_dev *dev __rte_unused,
+		int wait_to_complete __rte_unused) { return 0; }
+
+static int
+eth_rss_reta_update(struct rte_eth_dev *dev,
+		struct rte_eth_rss_reta_entry64 *reta_conf, uint16_t reta_size)
+{
+	int i, j;
+	struct pmd_internals *internal = dev->data->dev_private;
+
+	if (reta_size != internal->reta_size)
+		return -EINVAL;
+
+	rte_spinlock_lock(&internal->rss_lock);
+
+	/* Copy RETA table */
+	for (i = 0; i < (internal->reta_size / RTE_ETH_RETA_GROUP_SIZE); i++) {
+		internal->reta_conf[i].mask = reta_conf[i].mask;
+		for (j = 0; j < RTE_ETH_RETA_GROUP_SIZE; j++)
+			if ((reta_conf[i].mask >> j) & 0x01)
+				internal->reta_conf[i].reta[j] = reta_conf[i].reta[j];
+	}
+
+	rte_spinlock_unlock(&internal->rss_lock);
+
+	return 0;
+}
+
+static int
+eth_rss_reta_query(struct rte_eth_dev *dev,
+		struct rte_eth_rss_reta_entry64 *reta_conf, uint16_t reta_size)
+{
+	int i, j;
+	struct pmd_internals *internal = dev->data->dev_private;
+
+	if (reta_size != internal->reta_size)
+		return -EINVAL;
+
+	rte_spinlock_lock(&internal->rss_lock);
+
+	/* Copy RETA table */
+	for (i = 0; i < (internal->reta_size / RTE_ETH_RETA_GROUP_SIZE); i++) {
+		for (j = 0; j < RTE_ETH_RETA_GROUP_SIZE; j++)
+			if ((reta_conf[i].mask >> j) & 0x01)
+				reta_conf[i].reta[j] = internal->reta_conf[i].reta[j];
+	}
+
+	rte_spinlock_unlock(&internal->rss_lock);
+
+	return 0;
+}
+
+static int
+eth_rss_hash_update(struct rte_eth_dev *dev, struct rte_eth_rss_conf *rss_conf)
+{
+	struct pmd_internals *internal = dev->data->dev_private;
+
+	rte_spinlock_lock(&internal->rss_lock);
+
+	if ((rss_conf->rss_hf & internal->flow_type_rss_offloads) != 0)
+		dev->data->dev_conf.rx_adv_conf.rss_conf.rss_hf =
+				rss_conf->rss_hf & internal->flow_type_rss_offloads;
+
+	if (rss_conf->rss_key)
+		rte_memcpy(internal->rss_key, rss_conf->rss_key, 40);
+
+	rte_spinlock_unlock(&internal->rss_lock);
+
+	return 0;
+}
+
+static int
+eth_rss_hash_conf_get(struct rte_eth_dev *dev,
+		struct rte_eth_rss_conf *rss_conf)
+{
+	struct pmd_internals *internal = dev->data->dev_private;
+
+	rte_spinlock_lock(&internal->rss_lock);
+
+	rss_conf->rss_hf = dev->data->dev_conf.rx_adv_conf.rss_conf.rss_hf;
+	if (rss_conf->rss_key)
+		rte_memcpy(rss_conf->rss_key, internal->rss_key, 40);
+
+	rte_spinlock_unlock(&internal->rss_lock);
+
+	return 0;
+}
+
+static int
+eth_mac_address_set(__rte_unused struct rte_eth_dev *dev,
+		    __rte_unused struct rte_ether_addr *addr)
+{
+	return 0;
+}
+
+static int
+eth_dev_close(struct rte_eth_dev *dev)
+{
+	PMD_LOG(INFO, "Closing null ethdev on NUMA socket %u",
+			rte_socket_id());
+
+	if (rte_eal_process_type() != RTE_PROC_PRIMARY)
+		return 0;
+
+	/* mac_addrs must not be freed alone because part of dev_private */
+	dev->data->mac_addrs = NULL;
+
+	return 0;
+}
+
+static const struct eth_dev_ops ops = {
+	.dev_close = eth_dev_close,
+	.dev_start = eth_dev_start,
+	.dev_stop = eth_dev_stop,
+	.dev_configure = eth_dev_configure,
+	.dev_infos_get = eth_dev_info,
+	.rx_queue_setup = eth_rx_queue_setup,
+	.tx_queue_setup = eth_tx_queue_setup,
+	.rx_queue_release = eth_rx_queue_release,
+	.tx_queue_release = eth_tx_queue_release,
+	.mtu_set = eth_mtu_set,
+	.link_update = eth_link_update,
+	.mac_addr_set = eth_mac_address_set,
+	.stats_get = eth_stats_get,
+	.stats_reset = eth_stats_reset,
+	.reta_update = eth_rss_reta_update,
+	.reta_query = eth_rss_reta_query,
+	.rss_hash_update = eth_rss_hash_update,
+	.rss_hash_conf_get = eth_rss_hash_conf_get
+};
+
+static int
+eth_dev_null_create(struct rte_vdev_device *dev, struct pmd_options *args)
+{
+	const unsigned int nb_rx_queues = 1;
+	const unsigned int nb_tx_queues = 1;
+	struct rte_eth_dev_data *data;
+	struct pmd_internals *internals = NULL;
+	struct rte_eth_dev *eth_dev = NULL;
+
+	static const uint8_t default_rss_key[40] = {
+		0x6D, 0x5A, 0x56, 0xDA, 0x25, 0x5B, 0x0E, 0xC2, 0x41, 0x67, 0x25, 0x3D,
+		0x43, 0xA3, 0x8F, 0xB0, 0xD0, 0xCA, 0x2B, 0xCB, 0xAE, 0x7B, 0x30, 0xB4,
+		0x77, 0xCB, 0x2D, 0xA3, 0x80, 0x30, 0xF2, 0x0C, 0x6A, 0x42, 0xB7, 0x3B,
+		0xBE, 0xAC, 0x01, 0xFA
+	};
+
+	if (dev->device.numa_node == SOCKET_ID_ANY)
+		dev->device.numa_node = rte_socket_id();
+
+	PMD_LOG(INFO, "Creating null ethdev on numa socket %u",
+		dev->device.numa_node);
+
+	eth_dev = rte_eth_vdev_allocate(dev, sizeof(*internals));
+	if (!eth_dev)
+		return -ENOMEM;
+
+	/* now put it all together
+	 * - store queue data in internals,
+	 * - store numa_node info in ethdev data
+	 * - point eth_dev_data to internals
+	 * - and point eth_dev structure to new eth_dev_data structure
+	 */
+	/* NOTE: we'll replace the data element, of originally allocated eth_dev
+	 * so the nulls are local per-process */
+
+	internals = eth_dev->data->dev_private;
+	internals->packet_size = args->packet_size;
+	internals->packet_copy = args->packet_copy;
+	internals->no_rx = args->no_rx;
+	internals->port_id = eth_dev->data->port_id;
+	rte_eth_random_addr(internals->eth_addr.addr_bytes);
+
+	internals->flow_type_rss_offloads =  RTE_ETH_RSS_PROTO_MASK;
+	internals->reta_size = RTE_DIM(internals->reta_conf) * RTE_ETH_RETA_GROUP_SIZE;
+
+	rte_memcpy(internals->rss_key, default_rss_key, 40);
+
+	data = eth_dev->data;
+	data->nb_rx_queues = (uint16_t)nb_rx_queues;
+	data->nb_tx_queues = (uint16_t)nb_tx_queues;
+	data->dev_link = pmd_link;
+	data->mac_addrs = &internals->eth_addr;
+	data->promiscuous = 1;
+	data->all_multicast = 1;
+	data->dev_flags |= RTE_ETH_DEV_AUTOFILL_QUEUE_XSTATS;
+
+	eth_dev->dev_ops = &ops;
+
+	/* finally assign rx and tx ops */
+	if (internals->packet_copy) {
+		eth_dev->rx_pkt_burst = eth_null_copy_rx;
+		eth_dev->tx_pkt_burst = eth_null_copy_tx;
+	} else if (internals->no_rx) {
+		eth_dev->rx_pkt_burst = eth_null_no_rx;
+		eth_dev->tx_pkt_burst = eth_null_tx;
+	} else {
+		eth_dev->rx_pkt_burst = eth_null_rx;
+		eth_dev->tx_pkt_burst = eth_null_tx;
+	}
+
+	rte_eth_dev_probing_finish(eth_dev);
+	return 0;
+}
+
+static inline int
+get_packet_size_arg(const char *key __rte_unused,
+		const char *value, void *extra_args)
+{
+	const char *a = value;
+	unsigned int *packet_size = extra_args;
+
+	if ((value == NULL) || (extra_args == NULL))
+		return -EINVAL;
+
+	*packet_size = (unsigned int)strtoul(a, NULL, 0);
+	if (*packet_size == UINT_MAX)
+		return -1;
+
+	return 0;
+}
+
+static inline int
+get_packet_copy_arg(const char *key __rte_unused,
+		const char *value, void *extra_args)
+{
+	const char *a = value;
+	unsigned int *packet_copy = extra_args;
+
+	if ((value == NULL) || (extra_args == NULL))
+		return -EINVAL;
+
+	*packet_copy = (unsigned int)strtoul(a, NULL, 0);
+	if (*packet_copy == UINT_MAX)
+		return -1;
+
+	return 0;
+}
+
+static int
+get_packet_no_rx_arg(const char *key __rte_unused,
+		const char *value, void *extra_args)
+{
+	const char *a = value;
+	unsigned int no_rx;
+
+	if (value == NULL || extra_args == NULL)
+		return -EINVAL;
+
+	no_rx = (unsigned int)strtoul(a, NULL, 0);
+	if (no_rx != 0 && no_rx != 1)
+		return -1;
+
+	*(unsigned int *)extra_args = no_rx;
+	return 0;
+}
+
+static int
+rte_pmd_null_probe(struct rte_vdev_device *dev)
+{
+	const char *name, *params;
+	struct pmd_options args = {
+		.packet_copy = default_packet_copy,
+		.packet_size = default_packet_size,
+		.no_rx = default_no_rx,
+	};
+	struct rte_kvargs *kvlist = NULL;
+	struct rte_eth_dev *eth_dev;
+	int ret;
+
+	if (!dev)
+		return -EINVAL;
+
+	name = rte_vdev_device_name(dev);
+	params = rte_vdev_device_args(dev);
+	PMD_LOG(INFO, "Initializing pmd_null for %s", name);
+
+	if (rte_eal_process_type() == RTE_PROC_SECONDARY) {
+		struct pmd_internals *internals;
+		eth_dev = rte_eth_dev_attach_secondary(name);
+		if (!eth_dev) {
+			PMD_LOG(ERR, "Failed to probe %s", name);
+			return -1;
+		}
+		/* TODO: request info from primary to set up Rx and Tx */
+		eth_dev->dev_ops = &ops;
+		eth_dev->device = &dev->device;
+		internals = eth_dev->data->dev_private;
+		if (internals->packet_copy) {
+			eth_dev->rx_pkt_burst = eth_null_copy_rx;
+			eth_dev->tx_pkt_burst = eth_null_copy_tx;
+		} else if (internals->no_rx) {
+			eth_dev->rx_pkt_burst = eth_null_no_rx;
+			eth_dev->tx_pkt_burst = eth_null_tx;
+		} else {
+			eth_dev->rx_pkt_burst = eth_null_rx;
+			eth_dev->tx_pkt_burst = eth_null_tx;
+		}
+		rte_eth_dev_probing_finish(eth_dev);
+		return 0;
+	}
+
+	if (params != NULL) {
+		kvlist = rte_kvargs_parse(params, valid_arguments);
+		if (kvlist == NULL)
+			return -1;
+
+		ret = rte_kvargs_process(kvlist,
+				ETH_NULL_PACKET_SIZE_ARG,
+				&get_packet_size_arg, &args.packet_size);
+		if (ret < 0)
+			goto free_kvlist;
+
+
+		ret = rte_kvargs_process(kvlist,
+				ETH_NULL_PACKET_COPY_ARG,
+				&get_packet_copy_arg, &args.packet_copy);
+		if (ret < 0)
+			goto free_kvlist;
+
+		ret = rte_kvargs_process(kvlist,
+				ETH_NULL_PACKET_NO_RX_ARG,
+				&get_packet_no_rx_arg, &args.no_rx);
+		if (ret < 0)
+			goto free_kvlist;
+
+		if (args.no_rx && args.packet_copy) {
+			PMD_LOG(ERR,
+				"Both %s and %s arguments at the same time not supported",
+				ETH_NULL_PACKET_COPY_ARG,
+				ETH_NULL_PACKET_NO_RX_ARG);
+			goto free_kvlist;
+		}
+	}
+
+	PMD_LOG(INFO, "Configure pmd_null: packet size is %d, "
+			"packet copy is %s", args.packet_size,
+			args.packet_copy ? "enabled" : "disabled");
+
+	ret = eth_dev_null_create(dev, &args);
+
+free_kvlist:
+	rte_kvargs_free(kvlist);
+	return ret;
+}
+
+static int
+rte_pmd_null_remove(struct rte_vdev_device *dev)
+{
+	struct rte_eth_dev *eth_dev = NULL;
+
+	if (!dev)
+		return -EINVAL;
+
+	/* find the ethdev entry */
+	eth_dev = rte_eth_dev_allocated(rte_vdev_device_name(dev));
+	if (eth_dev == NULL)
+		return 0; /* port already released */
+
+	eth_dev_close(eth_dev);
+	rte_eth_dev_release_port(eth_dev);
+
+	return 0;
+}
+
+static struct rte_vdev_driver pmd_null_drv = {
+	.probe = rte_pmd_null_probe,
+	.remove = rte_pmd_null_remove,
+};
+
+RTE_PMD_REGISTER_VDEV(net_null, pmd_null_drv);
+RTE_PMD_REGISTER_ALIAS(net_null, eth_null);
+RTE_PMD_REGISTER_PARAM_STRING(net_null,
+	"size=<int> "
+	"copy=<int> "
+	ETH_NULL_PACKET_NO_RX_ARG "=0|1");
diff --git a/drivers/net/null/rte_eth_null.c b/drivers/net/null/rte_eth_null.c
index 6764cf2ec1..3a05af2e32 100644
--- a/drivers/net/null/rte_eth_null.c
+++ b/drivers/net/null/rte_eth_null.c
@@ -145,19 +145,12 @@ eth_null_no_rx(void *q __rte_unused, struct rte_mbuf **bufs __rte_unused,
 static uint16_t
 eth_null_tx(void *q, struct rte_mbuf **bufs, uint16_t nb_bufs)
 {
-	int i;
 	struct null_queue *h = q;
 
-	if ((q == NULL) || (bufs == NULL))
-		return 0;
-
-	for (i = 0; i < nb_bufs; i++)
-		rte_pktmbuf_free(bufs[i]);
+	rte_pktmbuf_free_bulk(bufs, nb_bufs);
+	rte_atomic_fetch_add_explicit(&h->tx_pkts, nb_bufs, rte_memory_order_relaxed);
 
-	/* NOTE: review for potential ordering optimization */
-	rte_atomic_fetch_add_explicit(&h->tx_pkts, i, rte_memory_order_seq_cst);
-
-	return i;
+	return nb_bufs;
 }
 
 static uint16_t
@@ -167,9 +160,6 @@ eth_null_copy_tx(void *q, struct rte_mbuf **bufs, uint16_t nb_bufs)
 	struct null_queue *h = q;
 	unsigned int packet_size;
 
-	if ((q == NULL) || (bufs == NULL))
-		return 0;
-
 	packet_size = h->internals->packet_size;
 	for (i = 0; i < nb_bufs; i++) {
 		rte_memcpy(h->dummy_packet, rte_pktmbuf_mtod(bufs[i], void *),
@@ -177,10 +167,8 @@ eth_null_copy_tx(void *q, struct rte_mbuf **bufs, uint16_t nb_bufs)
 		rte_pktmbuf_free(bufs[i]);
 	}
 
-	/* NOTE: review for potential ordering optimization */
-	rte_atomic_fetch_add_explicit(&h->tx_pkts, i, rte_memory_order_seq_cst);
-
-	return i;
+	rte_atomic_fetch_add_explicit(&h->tx_pkts, nb_bufs, rte_memory_order_relaxed);
+	return nb_bufs;
 }
 
 static int
@@ -314,6 +302,8 @@ eth_dev_info(struct rte_eth_dev *dev,
 	dev_info->max_rx_queues = RTE_DIM(internals->rx_null_queues);
 	dev_info->max_tx_queues = RTE_DIM(internals->tx_null_queues);
 	dev_info->min_rx_bufsize = 0;
+	dev_info->tx_offload_capa = RTE_ETH_TX_OFFLOAD_MULTI_SEGS | RTE_ETH_TX_OFFLOAD_MT_LOCKFREE;
+
 	dev_info->reta_size = internals->reta_size;
 	dev_info->flow_type_rss_offloads = internals->flow_type_rss_offloads;
 	dev_info->hash_key_size = sizeof(internals->rss_key);
@@ -346,10 +336,11 @@ eth_stats_get(struct rte_eth_dev *dev, struct rte_eth_stats *igb_stats)
 			RTE_MIN(dev->data->nb_tx_queues,
 				RTE_DIM(internal->tx_null_queues)));
 	for (i = 0; i < num_stats; i++) {
-		/* NOTE: review for atomic access */
-		igb_stats->q_opackets[i] =
-			internal->tx_null_queues[i].tx_pkts;
-		tx_total += igb_stats->q_opackets[i];
+		uint64_t pkts = rte_atomic_load_explicit(&internal->tx_null_queues[i].tx_pkts,
+						   rte_memory_order_relaxed);
+
+		igb_stats->q_opackets[i] = pkts;
+		tx_total += pkts;
 	}
 
 	igb_stats->ipackets = rx_total;
@@ -372,7 +363,6 @@ eth_stats_reset(struct rte_eth_dev *dev)
 		/* NOTE: review for atomic access */
 		internal->rx_null_queues[i].rx_pkts = 0;
 	for (i = 0; i < RTE_DIM(internal->tx_null_queues); i++)
-		/* NOTE: review for atomic access */
 		internal->tx_null_queues[i].tx_pkts = 0;
 
 	return 0;
-- 
2.47.2