RE: [PATCH 2/5] vhost: add per-virtqueue statistics support

["Xia, Chenbo" <chenbo.xia@intel.com>]

Hi Maxime,

> -----Original Message-----
> From: Maxime Coquelin <maxime.coquelin@redhat.com>
> Sent: Thursday, January 27, 2022 10:57 PM
> To: dev@dpdk.org; Xia, Chenbo <chenbo.xia@intel.com>;
> david.marchand@redhat.com
> Cc: Maxime Coquelin <maxime.coquelin@redhat.com>
> Subject: [PATCH 2/5] vhost: add per-virtqueue statistics support
> 
> This patch introduces new APIs for the application
> to query and reset per-virtqueue statistics. The
> patch also introduces generic counters.
> 
> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
> ---
>  lib/vhost/rte_vhost.h  |  89 +++++++++++++++++++++++++++++++++
>  lib/vhost/socket.c     |   4 +-
>  lib/vhost/version.map  |   5 ++
>  lib/vhost/vhost.c      | 109 ++++++++++++++++++++++++++++++++++++++++-
>  lib/vhost/vhost.h      |  18 ++++++-
>  lib/vhost/virtio_net.c |  53 ++++++++++++++++++++
>  6 files changed, 274 insertions(+), 4 deletions(-)
> 
> diff --git a/lib/vhost/rte_vhost.h b/lib/vhost/rte_vhost.h
> index b454c05868..e739091ca0 100644
> --- a/lib/vhost/rte_vhost.h
> +++ b/lib/vhost/rte_vhost.h
> @@ -37,6 +37,7 @@ extern "C" {
>  #define RTE_VHOST_USER_LINEARBUF_SUPPORT	(1ULL << 6)
>  #define RTE_VHOST_USER_ASYNC_COPY	(1ULL << 7)
>  #define RTE_VHOST_USER_NET_COMPLIANT_OL_FLAGS	(1ULL << 8)
> +#define RTE_VHOST_USER_NET_STATS_ENABLE	(1ULL << 9)
> 
>  /* Features. */
>  #ifndef VIRTIO_NET_F_GUEST_ANNOUNCE
> @@ -317,6 +318,32 @@ struct rte_vhost_power_monitor_cond {
>  	uint8_t match;
>  };
> 
> +/** Maximum name length for the statistics counters */
> +#define RTE_VHOST_STATS_NAME_SIZE 64
> +
> +/**
> + * Vhost virtqueue statistics structure
> + *
> + * This structure is used by rte_vhost_vring_stats_get() to provide
> + * virtqueue statistics to the calling application.
> + * It maps a name ID, corresponding to an index in the array returned
> + * by rte_vhost_vring_stats_get_names(), to a statistic value.
> + */
> +struct rte_vhost_stat {
> +	uint64_t id;    /**< The index in xstats name array. */
> +	uint64_t value; /**< The statistic counter value. */
> +};
> +
> +/**
> + * Vhost virtqueue statistic name element
> + *
> + * This structure is used by rte_vhost_vring_stats_get_anmes() to

Anmes -> names

> + * provide virtqueue statistics names to the calling application.
> + */
> +struct rte_vhost_stat_name {
> +	char name[RTE_VHOST_STATS_NAME_SIZE]; /**< The statistic name. */

Should we consider using ethdev one? Since vhost lib already depends on ethdev
lib.

> +};
> +
>  /**
>   * Convert guest physical address to host virtual address
>   *
> @@ -1059,6 +1086,68 @@ __rte_experimental
>  int
>  rte_vhost_slave_config_change(int vid, bool need_reply);
> 
> +/**
> + * Retrieve names of statistics of a Vhost virtqueue.
> + *
> + * There is an assumption that 'stat_names' and 'stats' arrays are
> matched
> + * by array index: stats_names[i].name => stats[i].value
> + *
> + * @param vid
> + *   vhost device ID
> + * @param queue_id
> + *   vhost queue index
> + * @param stats_names
> + *   array of at least size elements to be filled.
> + *   If set to NULL, the function returns the required number of elements.
> + * @param size
> + *   The number of elements in stats_names array.
> + * @return
> + *   A negative value on error, otherwise the number of entries filled in
> the
> + *   stats name array.
> + */
> +__rte_experimental
> +int
> +rte_vhost_vring_stats_get_names(int vid, uint16_t queue_id,
> +		struct rte_vhost_stat_name *name, unsigned int size);

'@param stats_names' and 'struct rte_vhost_stat_name *name' do not align and reports
error: 

http://mails.dpdk.org/archives/test-report/2022-March/270275.html

> +
> +/**
> + * Retrieve statistics of a Vhost virtqueue.
> + *
> + * There is an assumption that 'stat_names' and 'stats' arrays are
> matched
> + * by array index: stats_names[i].name => stats[i].value
> + *
> + * @param vid
> + *   vhost device ID
> + * @param queue_id
> + *   vhost queue index
> + * @param stats
> + *   A pointer to a table of structure of type rte_vhost_stat to be
> filled with
> + *   virtqueue statistics ids and values.
> + * @param n
> + *   The number of elements in stats array.
> + * @return
> + *   A negative value on error, otherwise the number of entries filled in
> the
> + *   stats table.
> + */
> +__rte_experimental
> +int
> +rte_vhost_vring_stats_get(int vid, uint16_t queue_id,
> +		struct rte_vhost_stat *stats, unsigned int n);
> +
> +/**
> + * Reset statistics of a Vhost virtqueue.
> + *
> + * @param vid
> + *   vhost device ID
> + * @param queue_id
> + *   vhost queue index
> + * @return
> + *   0 on success, a negative value on error.
> + */
> +__rte_experimental
> +int
> +rte_vhost_vring_stats_reset(int vid, uint16_t queue_id);
> +
>  #ifdef __cplusplus
>  }
>  #endif
> diff --git a/lib/vhost/socket.c b/lib/vhost/socket.c
> index c2f8013cd5..6020565fb6 100644
> --- a/lib/vhost/socket.c
> +++ b/lib/vhost/socket.c
> @@ -43,6 +43,7 @@ struct vhost_user_socket {
>  	bool linearbuf;
>  	bool async_copy;
>  	bool net_compliant_ol_flags;
> +	bool stats_enabled;
> 
>  	/*
>  	 * The "supported_features" indicates the feature bits the
> @@ -228,7 +229,7 @@ vhost_user_add_connection(int fd, struct
> vhost_user_socket *vsocket)
>  	vhost_set_ifname(vid, vsocket->path, size);
> 
>  	vhost_setup_virtio_net(vid, vsocket->use_builtin_virtio_net,
> -		vsocket->net_compliant_ol_flags);
> +		vsocket->net_compliant_ol_flags, vsocket->stats_enabled);
> 
>  	vhost_attach_vdpa_device(vid, vsocket->vdpa_dev);
> 
> @@ -864,6 +865,7 @@ rte_vhost_driver_register(const char *path, uint64_t
> flags)
>  	vsocket->linearbuf = flags & RTE_VHOST_USER_LINEARBUF_SUPPORT;
>  	vsocket->async_copy = flags & RTE_VHOST_USER_ASYNC_COPY;
>  	vsocket->net_compliant_ol_flags = flags &
> RTE_VHOST_USER_NET_COMPLIANT_OL_FLAGS;
> +	vsocket->stats_enabled = flags & RTE_VHOST_USER_NET_STATS_ENABLE;
> 
>  	if (vsocket->async_copy &&
>  		(flags & (RTE_VHOST_USER_IOMMU_SUPPORT |
> diff --git a/lib/vhost/version.map b/lib/vhost/version.map
> index a7ef7f1976..b83f79c87f 100644
> --- a/lib/vhost/version.map
> +++ b/lib/vhost/version.map
> @@ -84,6 +84,11 @@ EXPERIMENTAL {
> 
>  	# added in 21.11
>  	rte_vhost_get_monitor_addr;
> +
> +	# added in 22.03
> +	rte_vhost_vring_stats_get_names;
> +	rte_vhost_vring_stats_get;
> +	rte_vhost_vring_stats_reset;
>  };
> 
>  INTERNAL {
> diff --git a/lib/vhost/vhost.c b/lib/vhost/vhost.c
> index 42c01abf25..0c6a737aca 100644
> --- a/lib/vhost/vhost.c
> +++ b/lib/vhost/vhost.c
> @@ -28,6 +28,28 @@
>  struct virtio_net *vhost_devices[MAX_VHOST_DEVICE];
>  pthread_mutex_t vhost_dev_lock = PTHREAD_MUTEX_INITIALIZER;
> 
> +struct vhost_vq_stats_name_off {
> +	char name[RTE_VHOST_STATS_NAME_SIZE];
> +	unsigned int offset;
> +};
> +
> +static const struct vhost_vq_stats_name_off vhost_vq_stat_strings[] = {
> +	{"good_packets",           offsetof(struct vhost_virtqueue,
> stats.packets)},
> +	{"good_bytes",             offsetof(struct vhost_virtqueue,
> stats.bytes)},
> +	{"multicast_packets",      offsetof(struct vhost_virtqueue,
> stats.multicast)},
> +	{"broadcast_packets",      offsetof(struct vhost_virtqueue,
> stats.broadcast)},
> +	{"undersize_packets",      offsetof(struct vhost_virtqueue,
> stats.size_bins[0])},
> +	{"size_64_packets",        offsetof(struct vhost_virtqueue,
> stats.size_bins[1])},
> +	{"size_65_127_packets",    offsetof(struct vhost_virtqueue,
> stats.size_bins[2])},
> +	{"size_128_255_packets",   offsetof(struct vhost_virtqueue,
> stats.size_bins[3])},
> +	{"size_256_511_packets",   offsetof(struct vhost_virtqueue,
> stats.size_bins[4])},
> +	{"size_512_1023_packets",  offsetof(struct vhost_virtqueue,
> stats.size_bins[5])},
> +	{"size_1024_1518_packets", offsetof(struct vhost_virtqueue,
> stats.size_bins[6])},
> +	{"size_1519_max_packets",  offsetof(struct vhost_virtqueue,
> stats.size_bins[7])},
> +};
> +
> +#define VHOST_NB_VQ_STATS RTE_DIM(vhost_vq_stat_strings)
> +
>  /* Called with iotlb_lock read-locked */
>  uint64_t
>  __vhost_iova_to_vva(struct virtio_net *dev, struct vhost_virtqueue *vq,
> @@ -758,7 +780,7 @@ vhost_set_ifname(int vid, const char *if_name,
> unsigned int if_len)
>  }
> 
>  void
> -vhost_setup_virtio_net(int vid, bool enable, bool compliant_ol_flags)
> +vhost_setup_virtio_net(int vid, bool enable, bool compliant_ol_flags,
> bool stats_enabled)
>  {
>  	struct virtio_net *dev = get_device(vid);
> 
> @@ -773,6 +795,10 @@ vhost_setup_virtio_net(int vid, bool enable, bool
> compliant_ol_flags)
>  		dev->flags |= VIRTIO_DEV_LEGACY_OL_FLAGS;
>  	else
>  		dev->flags &= ~VIRTIO_DEV_LEGACY_OL_FLAGS;
> +	if (stats_enabled)
> +		dev->flags |= VIRTIO_DEV_STATS_ENABLED;
> +	else
> +		dev->flags &= ~VIRTIO_DEV_STATS_ENABLED;
>  }
> 
>  void
> @@ -1908,5 +1934,86 @@ rte_vhost_get_monitor_addr(int vid, uint16_t
> queue_id,
>  	return 0;
>  }
> 
> +
> +int
> +rte_vhost_vring_stats_get_names(int vid, uint16_t queue_id,
> +		struct rte_vhost_stat_name *name, unsigned int size)
> +{
> +	struct virtio_net *dev = get_device(vid);
> +	unsigned int i;
> +
> +	if (dev == NULL)
> +		return -1;
> +
> +	if (queue_id >= dev->nr_vring)
> +		return -1;
> +
> +	if (!(dev->flags & VIRTIO_DEV_STATS_ENABLED))
> +		return -1;
> +
> +	if (name == NULL || size < VHOST_NB_VQ_STATS)
> +		return VHOST_NB_VQ_STATS;
> +
> +	for (i = 0; i < VHOST_NB_VQ_STATS; i++)
> +		snprintf(name[i].name, sizeof(name[i].name), "%s_q%u_%s",
> +				(queue_id & 1) ? "rx" : "tx",
> +				queue_id / 2, vhost_vq_stat_strings[i].name);
> +
> +	return VHOST_NB_VQ_STATS;
> +}
> +
> +int
> +rte_vhost_vring_stats_get(int vid, uint16_t queue_id,
> +		struct rte_vhost_stat *stats, unsigned int n)
> +{
> +	struct virtio_net *dev = get_device(vid);
> +	struct vhost_virtqueue *vq;
> +	unsigned int i;
> +
> +	if (dev == NULL)
> +		return -1;
> +
> +	if (queue_id >= dev->nr_vring)
> +		return -1;
> +
> +	if (!(dev->flags & VIRTIO_DEV_STATS_ENABLED))
> +		return -1;
> +
> +	if (stats == NULL || n < VHOST_NB_VQ_STATS)
> +		return VHOST_NB_VQ_STATS;
> +
> +	vq = dev->virtqueue[queue_id];
> +
> +	rte_spinlock_lock(&vq->access_lock);
> +	for (i = 0; i < VHOST_NB_VQ_STATS; i++) {
> +		stats[i].value =
> +			*(uint64_t *)(((char *)vq) +
> vhost_vq_stat_strings[i].offset);
> +		stats[i].id = i;
> +	}
> +	rte_spinlock_unlock(&vq->access_lock);
> +
> +	return VHOST_NB_VQ_STATS;
> +}
> +
> +int rte_vhost_vring_stats_reset(int vid, uint16_t queue_id)
> +{
> +	struct virtio_net *dev = get_device(vid);
> +	struct vhost_virtqueue *vq;
> +
> +	if (dev == NULL)
> +		return -1;
> +
> +	if (queue_id >= dev->nr_vring)
> +		return -1;
> +

Guess you forgot to check VIRTIO_DEV_STATS_ENABLED?

> +	vq = dev->virtqueue[queue_id];
> +
> +	rte_spinlock_lock(&vq->access_lock);
> +	memset(&vq->stats, 0, sizeof(vq->stats));
> +	rte_spinlock_unlock(&vq->access_lock);
> +
> +	return 0;
> +}
> +
>  RTE_LOG_REGISTER_SUFFIX(vhost_config_log_level, config, INFO);
>  RTE_LOG_REGISTER_SUFFIX(vhost_data_log_level, data, WARNING);
> diff --git a/lib/vhost/vhost.h b/lib/vhost/vhost.h
> index 7085e0885c..4c151244c7 100644
> --- a/lib/vhost/vhost.h
> +++ b/lib/vhost/vhost.h
> @@ -38,6 +38,8 @@
>  #define VIRTIO_DEV_FEATURES_FAILED ((uint32_t)1 << 4)
>  /* Used to indicate that the virtio_net tx code should fill TX ol_flags
> */
>  #define VIRTIO_DEV_LEGACY_OL_FLAGS ((uint32_t)1 << 5)
> +/*  Used to indicate the application has requested statistics collection

Should be only one space between '/*' and 'Used' :P

Thanks,
Chenbo