i40evf: fix link info update
[dpdk.git] / examples / vhost / main.c
index a397eae..28c17af 100644 (file)
@@ -1,7 +1,7 @@
 /*-
  *   BSD LICENSE
  *
- *   Copyright(c) 2010-2014 Intel Corporation. All rights reserved.
+ *   Copyright(c) 2010-2015 Intel Corporation. All rights reserved.
  *   All rights reserved.
  *
  *   Redistribution and use in source and binary forms, with or without
 #include <rte_string_fns.h>
 #include <rte_malloc.h>
 #include <rte_virtio_net.h>
+#include <rte_ip.h>
+#include <rte_tcp.h>
 
 #include "main.h"
 
-#define MAX_QUEUES 512
+#ifndef MAX_QUEUES
+#define MAX_QUEUES 128
+#endif
 
 /* the maximum number of external ports supported */
 #define MAX_SUP_PORTS 1
 /*
  * Calculate the number of buffers needed per port
  */
-#define NUM_MBUFS_PER_PORT ((MAX_QUEUES*RTE_TEST_RX_DESC_DEFAULT) +            \
+#define NUM_MBUFS_PER_PORT ((MAX_QUEUES*RTE_TEST_RX_DESC_DEFAULT) +            \
                                                        (num_switching_cores*MAX_PKT_BURST) +                   \
                                                        (num_switching_cores*RTE_TEST_TX_DESC_DEFAULT) +\
-                                                       (num_switching_cores*MBUF_CACHE_SIZE))
+                                                       ((num_switching_cores+1)*MBUF_CACHE_SIZE))
 
-#define MBUF_CACHE_SIZE 128
-#define MBUF_SIZE (2048 + sizeof(struct rte_mbuf) + RTE_PKTMBUF_HEADROOM)
+#define MBUF_CACHE_SIZE        128
+#define MBUF_DATA_SIZE RTE_MBUF_DEFAULT_BUF_SIZE
 
 /*
  * No frame data buffer allocated from host are required for zero copy
  * implementation, guest will allocate the frame data buffer, and vhost
  * directly use it.
  */
-#define VIRTIO_DESCRIPTOR_LEN_ZCP 1518
-#define MBUF_SIZE_ZCP (VIRTIO_DESCRIPTOR_LEN_ZCP + sizeof(struct rte_mbuf) \
-       + RTE_PKTMBUF_HEADROOM)
+#define VIRTIO_DESCRIPTOR_LEN_ZCP      RTE_MBUF_DEFAULT_DATAROOM
+#define MBUF_DATA_SIZE_ZCP             RTE_MBUF_DEFAULT_BUF_SIZE
 #define MBUF_CACHE_SIZE_ZCP 0
 
-#define MAX_PKT_BURST 32               /* Max burst size for RX/TX */
-#define BURST_TX_DRAIN_US 100  /* TX drain every ~100us */
+#define MAX_PKT_BURST 32               /* Max burst size for RX/TX */
+#define BURST_TX_DRAIN_US 100  /* TX drain every ~100us */
 
-#define BURST_RX_WAIT_US 15    /* Defines how long we wait between retries on RX */
+#define BURST_RX_WAIT_US 15    /* Defines how long we wait between retries on RX */
 #define BURST_RX_RETRIES 4             /* Number of retries on RX. */
 
 #define JUMBO_FRAME_MAX_SIZE    0x2600
 /* Number of descriptors per cacheline. */
 #define DESC_PER_CACHELINE (RTE_CACHE_LINE_SIZE / sizeof(struct vring_desc))
 
+#define MBUF_EXT_MEM(mb)   (rte_mbuf_from_indirect(mb) != (mb))
+
 /* mask of enabled ports */
 static uint32_t enabled_port_mask = 0;
 
@@ -196,6 +201,13 @@ typedef enum {
 static uint32_t enable_stats = 0;
 /* Enable retries on RX. */
 static uint32_t enable_retry = 1;
+
+/* Disable TX checksum offload */
+static uint32_t enable_tx_csum;
+
+/* Disable TSO offload */
+static uint32_t enable_tso;
+
 /* Specify timeout (in useconds) between retries on RX. */
 static uint32_t burst_rx_delay_time = BURST_RX_WAIT_US;
 /* Specify the number of retries on RX. */
@@ -291,20 +303,6 @@ struct vlan_ethhdr {
        __be16          h_vlan_encapsulated_proto;
 };
 
-/* IPv4 Header */
-struct ipv4_hdr {
-       uint8_t  version_ihl;           /**< version and header length */
-       uint8_t  type_of_service;       /**< type of service */
-       uint16_t total_length;          /**< length of packet */
-       uint16_t packet_id;             /**< packet ID */
-       uint16_t fragment_offset;       /**< fragmentation offset */
-       uint8_t  time_to_live;          /**< time to live */
-       uint8_t  next_proto_id;         /**< protocol ID */
-       uint16_t hdr_checksum;          /**< header checksum */
-       uint32_t src_addr;              /**< source address */
-       uint32_t dst_addr;              /**< destination address */
-} __attribute__((__packed__));
-
 /* Header lengths. */
 #define VLAN_HLEN       4
 #define VLAN_ETH_HLEN   18
@@ -440,6 +438,14 @@ port_init(uint8_t port)
 
        if (port >= rte_eth_dev_count()) return -1;
 
+       if (enable_tx_csum == 0)
+               rte_vhost_feature_disable(1ULL << VIRTIO_NET_F_CSUM);
+
+       if (enable_tso == 0) {
+               rte_vhost_feature_disable(1ULL << VIRTIO_NET_F_HOST_TSO4);
+               rte_vhost_feature_disable(1ULL << VIRTIO_NET_F_HOST_TSO6);
+       }
+
        rx_rings = (uint16_t)dev_info.max_rx_queues;
        /* Configure ethernet device. */
        retval = rte_eth_dev_configure(port, rx_rings, tx_rings, &port_conf);
@@ -575,7 +581,9 @@ us_vhost_usage(const char *prgname)
        "               --rx-desc-num [0-N]: the number of descriptors on rx, "
                        "used only when zero copy is enabled.\n"
        "               --tx-desc-num [0-N]: the number of descriptors on tx, "
-                       "used only when zero copy is enabled.\n",
+                       "used only when zero copy is enabled.\n"
+       "               --tx-csum [0|1] disable/enable TX checksum offload.\n"
+       "               --tso [0|1] disable/enable TCP segment offload.\n",
               prgname);
 }
 
@@ -601,6 +609,8 @@ us_vhost_parse_args(int argc, char **argv)
                {"zero-copy", required_argument, NULL, 0},
                {"rx-desc-num", required_argument, NULL, 0},
                {"tx-desc-num", required_argument, NULL, 0},
+               {"tx-csum", required_argument, NULL, 0},
+               {"tso", required_argument, NULL, 0},
                {NULL, 0, 0, 0},
        };
 
@@ -655,6 +665,28 @@ us_vhost_parse_args(int argc, char **argv)
                                }
                        }
 
+                       /* Enable/disable TX checksum offload. */
+                       if (!strncmp(long_option[option_index].name, "tx-csum", MAX_LONG_OPT_SZ)) {
+                               ret = parse_num_opt(optarg, 1);
+                               if (ret == -1) {
+                                       RTE_LOG(INFO, VHOST_CONFIG, "Invalid argument for tx-csum [0|1]\n");
+                                       us_vhost_usage(prgname);
+                                       return -1;
+                               } else
+                                       enable_tx_csum = ret;
+                       }
+
+                       /* Enable/disable TSO offload. */
+                       if (!strncmp(long_option[option_index].name, "tso", MAX_LONG_OPT_SZ)) {
+                               ret = parse_num_opt(optarg, 1);
+                               if (ret == -1) {
+                                       RTE_LOG(INFO, VHOST_CONFIG, "Invalid argument for tso [0|1]\n");
+                                       us_vhost_usage(prgname);
+                                       return -1;
+                               } else
+                                       enable_tso = ret;
+                       }
+
                        /* Specify the retries delay time (in useconds) on RX. */
                        if (!strncmp(long_option[option_index].name, "rx-retry-delay", MAX_LONG_OPT_SZ)) {
                                ret = parse_num_opt(optarg, INT32_MAX);
@@ -745,19 +777,6 @@ us_vhost_parse_args(int argc, char **argv)
                                        return -1;
                                } else
                                        zero_copy = ret;
-
-                               if (zero_copy) {
-#ifdef RTE_MBUF_REFCNT
-                                       RTE_LOG(ERR, VHOST_CONFIG, "Before running "
-                                       "zero copy vhost APP, please "
-                                       "disable RTE_MBUF_REFCNT\n"
-                                       "in config file and then rebuild DPDK "
-                                       "core lib!\n"
-                                       "Otherwise please disable zero copy "
-                                       "flag in command line!\n");
-                                       return -1;
-#endif
-                               }
                        }
 
                        /* Specify the descriptor number on RX. */
@@ -921,7 +940,7 @@ gpa_to_hpa(struct vhost_dev  *vdev, uint64_t guest_pa,
 static inline int __attribute__((always_inline))
 ether_addr_cmp(struct ether_addr *ea, struct ether_addr *eb)
 {
-       return (((*(uint64_t *)ea ^ *(uint64_t *)eb) & MAC_ADDR_CMP) == 0);
+       return ((*(uint64_t *)ea ^ *(uint64_t *)eb) & MAC_ADDR_CMP) == 0;
 }
 
 /*
@@ -1062,8 +1081,8 @@ virtio_tx_local(struct vhost_dev *vdev, struct rte_mbuf *m)
                                        rte_atomic64_add(
                                        &dev_statistics[tdev->device_fh].rx_atomic,
                                        ret);
-                                       dev_statistics[tdev->device_fh].tx_total++;
-                                       dev_statistics[tdev->device_fh].tx += ret;
+                                       dev_statistics[dev->device_fh].tx_total++;
+                                       dev_statistics[dev->device_fh].tx += ret;
                                }
                        }
 
@@ -1117,7 +1136,7 @@ find_local_dest(struct virtio_net *dev, struct rte_mbuf *m,
                        "(%"PRIu64") TX: pkt to local VM device id:"
                        "(%"PRIu64") vlan tag: %d.\n",
                        dev->device_fh, dev_ll->vdev->dev->device_fh,
-                       vlan_tag);
+                       (int)*vlan_tag);
 
                        break;
                }
@@ -1126,6 +1145,34 @@ find_local_dest(struct virtio_net *dev, struct rte_mbuf *m,
        return 0;
 }
 
+static uint16_t
+get_psd_sum(void *l3_hdr, uint64_t ol_flags)
+{
+       if (ol_flags & PKT_TX_IPV4)
+               return rte_ipv4_phdr_cksum(l3_hdr, ol_flags);
+       else /* assume ethertype == ETHER_TYPE_IPv6 */
+               return rte_ipv6_phdr_cksum(l3_hdr, ol_flags);
+}
+
+static void virtio_tx_offload(struct rte_mbuf *m)
+{
+       void *l3_hdr;
+       struct ipv4_hdr *ipv4_hdr = NULL;
+       struct tcp_hdr *tcp_hdr = NULL;
+       struct ether_hdr *eth_hdr = rte_pktmbuf_mtod(m, struct ether_hdr *);
+
+       l3_hdr = (char *)eth_hdr + m->l2_len;
+
+       if (m->ol_flags & PKT_TX_IPV4) {
+               ipv4_hdr = l3_hdr;
+               ipv4_hdr->hdr_checksum = 0;
+               m->ol_flags |= PKT_TX_IP_CKSUM;
+       }
+
+       tcp_hdr = (struct tcp_hdr *)((char *)l3_hdr + m->l3_len);
+       tcp_hdr->cksum = get_psd_sum(l3_hdr, m->ol_flags);
+}
+
 /*
  * This function routes the TX packet to the correct interface. This may be a local device
  * or the physical port.
@@ -1168,7 +1215,7 @@ virtio_tx_route(struct vhost_dev *vdev, struct rte_mbuf *m, uint16_t vlan_tag)
                        (vh->vlan_tci != vlan_tag_be))
                        vh->vlan_tci = vlan_tag_be;
        } else {
-               m->ol_flags = PKT_TX_VLAN_PKT;
+               m->ol_flags |= PKT_TX_VLAN_PKT;
 
                /*
                 * Find the right seg to adjust the data len when offset is
@@ -1192,6 +1239,9 @@ virtio_tx_route(struct vhost_dev *vdev, struct rte_mbuf *m, uint16_t vlan_tag)
                m->vlan_tci = vlan_tag;
        }
 
+       if (m->ol_flags & PKT_TX_TCP_SEG)
+               virtio_tx_offload(m);
+
        tx_q->m_table[len] = m;
        len++;
        if (enable_stats) {
@@ -1346,8 +1396,10 @@ switch_worker(__attribute__((unused)) void *arg)
                                                        rte_pktmbuf_free(pkts_burst[--tx_count]);
                                        }
                                }
-                               while (tx_count)
-                                       virtio_tx_route(vdev, pkts_burst[--tx_count], (uint16_t)dev->device_fh);
+                               for (i = 0; i < tx_count; ++i) {
+                                       virtio_tx_route(vdev, pkts_burst[i],
+                                               vlan_tags[(uint16_t)dev->device_fh]);
+                               }
                        }
 
                        /*move to the next device in the list*/
@@ -1445,7 +1497,7 @@ put_desc_to_used_list_zcp(struct vhost_virtqueue *vq, uint16_t desc_idx)
 
        /* Kick the guest if necessary. */
        if (!(vq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT))
-               eventfd_write((int)vq->kickfd, 1);
+               eventfd_write(vq->callfd, (eventfd_t)1);
 }
 
 /*
@@ -1461,7 +1513,8 @@ attach_rxmbuf_zcp(struct virtio_net *dev)
        uint64_t buff_addr, phys_addr;
        struct vhost_virtqueue *vq;
        struct vring_desc *desc;
-       struct rte_mbuf *mbuf = NULL;
+       void *obj = NULL;
+       struct rte_mbuf *mbuf;
        struct vpool *vpool;
        hpa_type addr_type;
        struct vhost_dev *vdev = (struct vhost_dev *)dev->priv;
@@ -1512,7 +1565,8 @@ attach_rxmbuf_zcp(struct virtio_net *dev)
                }
        } while (unlikely(phys_addr == 0));
 
-       rte_ring_sc_dequeue(vpool->ring, (void **)&mbuf);
+       rte_ring_sc_dequeue(vpool->ring, &obj);
+       mbuf = obj;
        if (unlikely(mbuf == NULL)) {
                LOG_DEBUG(VHOST_DATA,
                        "(%"PRIu64") in attach_rxmbuf_zcp: "
@@ -1529,7 +1583,7 @@ attach_rxmbuf_zcp(struct virtio_net *dev)
                        "size required: %d\n",
                        dev->device_fh, desc->len, desc_idx, vpool->buf_size);
                put_desc_to_used_list_zcp(vq, desc_idx);
-               rte_ring_sp_enqueue(vpool->ring, (void *)mbuf);
+               rte_ring_sp_enqueue(vpool->ring, obj);
                return;
        }
 
@@ -1561,7 +1615,7 @@ attach_rxmbuf_zcp(struct virtio_net *dev)
 static inline void pktmbuf_detach_zcp(struct rte_mbuf *m)
 {
        const struct rte_mempool *mp = m->pool;
-       void *buf = RTE_MBUF_TO_BADDR(m);
+       void *buf = rte_mbuf_to_baddr(m);
        uint32_t buf_ofs;
        uint32_t buf_len = mp->elt_size - sizeof(*m);
        m->buf_physaddr = rte_mempool_virt2phy(mp, m) + sizeof(*m);
@@ -1601,7 +1655,7 @@ txmbuf_clean_zcp(struct virtio_net *dev, struct vpool *vpool)
 
        for (index = 0; index < mbuf_count; index++) {
                mbuf = __rte_mbuf_raw_alloc(vpool->pool);
-               if (likely(RTE_MBUF_INDIRECT(mbuf)))
+               if (likely(MBUF_EXT_MEM(mbuf)))
                        pktmbuf_detach_zcp(mbuf);
                rte_ring_sp_enqueue(vpool->ring, mbuf);
 
@@ -1638,7 +1692,7 @@ txmbuf_clean_zcp(struct virtio_net *dev, struct vpool *vpool)
 
        /* Kick guest if required. */
        if (!(vq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT))
-               eventfd_write((int)vq->kickfd, 1);
+               eventfd_write(vq->callfd, (eventfd_t)1);
 
        return 0;
 }
@@ -1664,7 +1718,7 @@ static void mbuf_destroy_zcp(struct vpool *vpool)
        for (index = 0; index < mbuf_count; index++) {
                mbuf = __rte_mbuf_raw_alloc(vpool->pool);
                if (likely(mbuf != NULL)) {
-                       if (likely(RTE_MBUF_INDIRECT(mbuf)))
+                       if (likely(MBUF_EXT_MEM(mbuf)))
                                pktmbuf_detach_zcp(mbuf);
                        rte_ring_sp_enqueue(vpool->ring, (void *)mbuf);
                }
@@ -1786,7 +1840,7 @@ virtio_dev_rx_zcp(struct virtio_net *dev, struct rte_mbuf **pkts,
 
        /* Kick the guest if necessary. */
        if (!(vq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT))
-               eventfd_write((int)vq->kickfd, 1);
+               eventfd_write(vq->callfd, (eventfd_t)1);
 
        return count;
 }
@@ -1801,7 +1855,8 @@ virtio_tx_route_zcp(struct virtio_net *dev, struct rte_mbuf *m,
 {
        struct mbuf_table *tx_q;
        struct rte_mbuf **m_table;
-       struct rte_mbuf *mbuf = NULL;
+       void *obj = NULL;
+       struct rte_mbuf *mbuf;
        unsigned len, ret, offset = 0;
        struct vpool *vpool;
        uint16_t vlan_tag = (uint16_t)vlan_tags[(uint16_t)dev->device_fh];
@@ -1813,7 +1868,8 @@ virtio_tx_route_zcp(struct virtio_net *dev, struct rte_mbuf *m,
 
        /* Allocate an mbuf and populate the structure. */
        vpool = &vpool_array[MAX_QUEUES + vmdq_rx_q];
-       rte_ring_sc_dequeue(vpool->ring, (void **)&mbuf);
+       rte_ring_sc_dequeue(vpool->ring, &obj);
+       mbuf = obj;
        if (unlikely(mbuf == NULL)) {
                struct vhost_virtqueue *vq = dev->virtqueue[VIRTIO_TXQ];
                RTE_LOG(ERR, VHOST_DATA,
@@ -1853,7 +1909,7 @@ virtio_tx_route_zcp(struct virtio_net *dev, struct rte_mbuf *m,
                mbuf->buf_physaddr = m->buf_physaddr;
                mbuf->buf_addr = m->buf_addr;
        }
-       mbuf->ol_flags = PKT_TX_VLAN_PKT;
+       mbuf->ol_flags |= PKT_TX_VLAN_PKT;
        mbuf->vlan_tci = vlan_tag;
        mbuf->l2_len = sizeof(struct ether_hdr);
        mbuf->l3_len = sizeof(struct ipv4_hdr);
@@ -2287,7 +2343,7 @@ alloc_data_ll(uint32_t size)
        }
        ll_new[i].next = NULL;
 
-       return (ll_new);
+       return ll_new;
 }
 
 /*
@@ -2626,9 +2682,10 @@ new_device (struct virtio_net *dev)
 
                }
 
-               vdev->regions_hpa = (struct virtio_memory_regions_hpa *) rte_zmalloc("vhost hpa region",
-                       sizeof(struct virtio_memory_regions_hpa) * vdev->nregions_hpa,
-                       RTE_CACHE_LINE_SIZE);
+               vdev->regions_hpa = rte_calloc("vhost hpa region",
+                                              vdev->nregions_hpa,
+                                              sizeof(struct virtio_memory_regions_hpa),
+                                              RTE_CACHE_LINE_SIZE);
                if (vdev->regions_hpa == NULL) {
                        RTE_LOG(ERR, VHOST_CONFIG, "Cannot allocate memory for hpa region\n");
                        rte_free(vdev);
@@ -2757,8 +2814,7 @@ new_device (struct virtio_net *dev)
                RTE_LOG(INFO, VHOST_DATA, "(%"PRIu64") Failed to add device to data core\n", dev->device_fh);
                vdev->ready = DEVICE_SAFE_REMOVE;
                destroy_device(dev);
-               if (vdev->regions_hpa)
-                       rte_free(vdev->regions_hpa);
+               rte_free(vdev->regions_hpa);
                rte_free(vdev);
                return -1;
        }
@@ -2855,12 +2911,8 @@ static void
 setup_mempool_tbl(int socket, uint32_t index, char *pool_name,
        char *ring_name, uint32_t nb_mbuf)
 {
-       uint16_t roomsize = VIRTIO_DESCRIPTOR_LEN_ZCP + RTE_PKTMBUF_HEADROOM;
-       vpool_array[index].pool
-               = rte_mempool_create(pool_name, nb_mbuf, MBUF_SIZE_ZCP,
-               MBUF_CACHE_SIZE_ZCP, sizeof(struct rte_pktmbuf_pool_private),
-               rte_pktmbuf_pool_init, (void *)(uintptr_t)roomsize,
-               rte_pktmbuf_init, NULL, socket, 0);
+       vpool_array[index].pool = rte_pktmbuf_pool_create(pool_name, nb_mbuf,
+               MBUF_CACHE_SIZE_ZCP, 0, MBUF_DATA_SIZE_ZCP, socket);
        if (vpool_array[index].pool != NULL) {
                vpool_array[index].ring
                        = rte_ring_create(ring_name,
@@ -2881,12 +2933,22 @@ setup_mempool_tbl(int socket, uint32_t index, char *pool_name,
                }
 
                /* Need consider head room. */
-               vpool_array[index].buf_size = roomsize - RTE_PKTMBUF_HEADROOM;
+               vpool_array[index].buf_size = VIRTIO_DESCRIPTOR_LEN_ZCP;
        } else {
                rte_exit(EXIT_FAILURE, "mempool_create(%s) failed", pool_name);
        }
 }
 
+/* When we receive a INT signal, unregister vhost driver */
+static void
+sigint_handler(__rte_unused int signum)
+{
+       /* Unregister vhost driver. */
+       int ret = rte_vhost_driver_unregister((char *)&dev_basename);
+       if (ret != 0)
+               rte_exit(EXIT_FAILURE, "vhost driver unregister failure.\n");
+       exit(0);
+}
 
 /*
  * Main function, does initialisation and calls the per-lcore functions. The CUSE
@@ -2902,6 +2964,9 @@ main(int argc, char *argv[])
        uint8_t portid;
        uint16_t queue_id;
        static pthread_t tid;
+       char thread_name[RTE_MAX_THREAD_NAME_LEN];
+
+       signal(SIGINT, sigint_handler);
 
        /* init EAL */
        ret = rte_eal_init(argc, argv);
@@ -2944,15 +3009,9 @@ main(int argc, char *argv[])
 
        if (zero_copy == 0) {
                /* Create the mbuf pool. */
-               mbuf_pool = rte_mempool_create(
-                               "MBUF_POOL",
-                               NUM_MBUFS_PER_PORT
-                               * valid_num_ports,
-                               MBUF_SIZE, MBUF_CACHE_SIZE,
-                               sizeof(struct rte_pktmbuf_pool_private),
-                               rte_pktmbuf_pool_init, NULL,
-                               rte_pktmbuf_init, NULL,
-                               rte_socket_id(), 0);
+               mbuf_pool = rte_pktmbuf_pool_create("MBUF_POOL",
+                       NUM_MBUFS_PER_PORT * valid_num_ports, MBUF_CACHE_SIZE,
+                       0, MBUF_DATA_SIZE, rte_socket_id());
                if (mbuf_pool == NULL)
                        rte_exit(EXIT_FAILURE, "Cannot create mbuf pool\n");
 
@@ -3028,8 +3087,19 @@ main(int argc, char *argv[])
        memset(&dev_statistics, 0, sizeof(dev_statistics));
 
        /* Enable stats if the user option is set. */
-       if (enable_stats)
-               pthread_create(&tid, NULL, (void*)print_stats, NULL );
+       if (enable_stats) {
+               ret = pthread_create(&tid, NULL, (void *)print_stats, NULL);
+               if (ret != 0)
+                       rte_exit(EXIT_FAILURE,
+                               "Cannot create print-stats thread\n");
+
+               /* Set thread_name for aid in debugging.  */
+               snprintf(thread_name, RTE_MAX_THREAD_NAME_LEN, "print-stats");
+               ret = rte_thread_setname(tid, thread_name);
+               if (ret != 0)
+                       RTE_LOG(ERR, VHOST_CONFIG,
+                               "Cannot set print-stats name\n");
+       }
 
        /* Launch all data cores. */
        if (zero_copy == 0) {
@@ -3073,10 +3143,10 @@ main(int argc, char *argv[])
        if (mergeable == 0)
                rte_vhost_feature_disable(1ULL << VIRTIO_NET_F_MRG_RXBUF);
 
-       /* Register CUSE device to handle IOCTLs. */
+       /* Register vhost(cuse or user) driver to handle vhost messages. */
        ret = rte_vhost_driver_register((char *)&dev_basename);
        if (ret != 0)
-               rte_exit(EXIT_FAILURE,"CUSE device setup failure.\n");
+               rte_exit(EXIT_FAILURE, "vhost driver register failure.\n");
 
        rte_vhost_driver_callback_register(&virtio_net_device_ops);
 
@@ -3085,4 +3155,3 @@ main(int argc, char *argv[])
        return 0;
 
 }
-