[dpdk-dev] [PATCH v4 3/3] vhost: optimize vhost virtqueue struct

[Xia, Chenbo]

> -----Original Message-----
> From: Maxime Coquelin <maxime.coquelin at redhat.com>
> Sent: Tuesday, March 23, 2021 5:02 PM
> To: dev at dpdk.org; Xia, Chenbo <chenbo.xia at intel.com>; amorenoz at redhat.com;
> david.marchand at redhat.com; olivier.matz at 6wind.com; bnemeth at redhat.com
> Cc: Maxime Coquelin <maxime.coquelin at redhat.com>
> Subject: [PATCH v4 3/3] vhost: optimize vhost virtqueue struct
> 
> This patch moves vhost_virtqueue struct fields in order
> to both optimize packing and move hot fields on the first
> cachelines.
> 
> Signed-off-by: Maxime Coquelin <maxime.coquelin at redhat.com>
> ---
>  lib/librte_vhost/vhost.c      |  6 ++--
>  lib/librte_vhost/vhost.h      | 54 ++++++++++++++++++-----------------
>  lib/librte_vhost/vhost_user.c | 23 +++++++--------
>  lib/librte_vhost/virtio_net.c | 12 ++++----
>  4 files changed, 48 insertions(+), 47 deletions(-)
> 
> diff --git a/lib/librte_vhost/vhost.c b/lib/librte_vhost/vhost.c
> index a8032e3ba1..04d63b2f02 100644
> --- a/lib/librte_vhost/vhost.c
> +++ b/lib/librte_vhost/vhost.c
> @@ -524,7 +524,7 @@ vring_translate(struct virtio_net *dev, struct
> vhost_virtqueue *vq)
>  	if (log_translate(dev, vq) < 0)
>  		return -1;
> 
> -	vq->access_ok = 1;
> +	vq->access_ok = true;
> 
>  	return 0;
>  }
> @@ -535,7 +535,7 @@ vring_invalidate(struct virtio_net *dev, struct
> vhost_virtqueue *vq)
>  	if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))
>  		vhost_user_iotlb_wr_lock(vq);
> 
> -	vq->access_ok = 0;
> +	vq->access_ok = false;
>  	vq->desc = NULL;
>  	vq->avail = NULL;
>  	vq->used = NULL;
> @@ -1451,7 +1451,7 @@ rte_vhost_rx_queue_count(int vid, uint16_t qid)
> 
>  	rte_spinlock_lock(&vq->access_lock);
> 
> -	if (unlikely(vq->enabled == 0 || vq->avail == NULL))
> +	if (unlikely(!vq->enabled || vq->avail == NULL))
>  		goto out;
> 
>  	ret = *((volatile uint16_t *)&vq->avail->idx) - vq->last_avail_idx;
> diff --git a/lib/librte_vhost/vhost.h b/lib/librte_vhost/vhost.h
> index 3a71dfeed9..f628714c24 100644
> --- a/lib/librte_vhost/vhost.h
> +++ b/lib/librte_vhost/vhost.h
> @@ -133,7 +133,7 @@ struct vhost_virtqueue {
>  		struct vring_used	*used;
>  		struct vring_packed_desc_event *device_event;
>  	};
> -	uint32_t		size;
> +	uint16_t		size;
> 
>  	uint16_t		last_avail_idx;
>  	uint16_t		last_used_idx;
> @@ -143,29 +143,12 @@ struct vhost_virtqueue {
>  #define VIRTIO_INVALID_EVENTFD		(-1)
>  #define VIRTIO_UNINITIALIZED_EVENTFD	(-2)
> 
> -	int			enabled;
> -	int			access_ok;
> -	int			ready;
> -	int			notif_enable;
> -#define VIRTIO_UNINITIALIZED_NOTIF	(-1)
> +	bool			enabled;
> +	bool			access_ok;
> +	bool			ready;
> 
>  	rte_spinlock_t		access_lock;
> 
> -	/* Used to notify the guest (trigger interrupt) */
> -	int			callfd;
> -	/* Currently unused as polling mode is enabled */
> -	int			kickfd;
> -
> -	/* Physical address of used ring, for logging */
> -	uint64_t		log_guest_addr;
> -
> -	/* inflight share memory info */
> -	union {
> -		struct rte_vhost_inflight_info_split *inflight_split;
> -		struct rte_vhost_inflight_info_packed *inflight_packed;
> -	};
> -	struct rte_vhost_resubmit_info *resubmit_inflight;
> -	uint64_t		global_counter;
> 
>  	union {
>  		struct vring_used_elem  *shadow_used_split;
> @@ -176,22 +159,36 @@ struct vhost_virtqueue {
>  	uint16_t		shadow_aligned_idx;
>  	/* Record packed ring first dequeue desc index */
>  	uint16_t		shadow_last_used_idx;
> -	struct vhost_vring_addr ring_addrs;
> 
> -	struct batch_copy_elem	*batch_copy_elems;
>  	uint16_t		batch_copy_nb_elems;
> +	struct batch_copy_elem	*batch_copy_elems;
>  	bool			used_wrap_counter;
>  	bool			avail_wrap_counter;
> 
> -	struct log_cache_entry *log_cache;
> -	uint16_t log_cache_nb_elem;
> +	/* Physical address of used ring, for logging */
> +	uint16_t		log_cache_nb_elem;
> +	uint64_t		log_guest_addr;
> +	struct log_cache_entry	*log_cache;
> 
>  	rte_rwlock_t	iotlb_lock;
>  	rte_rwlock_t	iotlb_pending_lock;
>  	struct rte_mempool *iotlb_pool;
>  	TAILQ_HEAD(, vhost_iotlb_entry) iotlb_list;
> -	int				iotlb_cache_nr;
>  	TAILQ_HEAD(, vhost_iotlb_entry) iotlb_pending_list;
> +	int				iotlb_cache_nr;
> +
> +	/* Used to notify the guest (trigger interrupt) */
> +	int			callfd;
> +	/* Currently unused as polling mode is enabled */
> +	int			kickfd;
> +
> +	/* inflight share memory info */
> +	union {
> +		struct rte_vhost_inflight_info_split *inflight_split;
> +		struct rte_vhost_inflight_info_packed *inflight_packed;
> +	};
> +	struct rte_vhost_resubmit_info *resubmit_inflight;
> +	uint64_t		global_counter;
> 
>  	/* operation callbacks for async dma */
>  	struct rte_vhost_async_channel_ops	async_ops;
> @@ -212,6 +209,11 @@ struct vhost_virtqueue {
>  	bool		async_inorder;
>  	bool		async_registered;
>  	uint16_t	async_threshold;
> +
> +	int			notif_enable;
> +#define VIRTIO_UNINITIALIZED_NOTIF	(-1)
> +
> +	struct vhost_vring_addr ring_addrs;
>  } __rte_cache_aligned;
> 
>  /* Virtio device status as per Virtio specification */
> diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c
> index 4d9e76e49e..2f4f89aeac 100644
> --- a/lib/librte_vhost/vhost_user.c
> +++ b/lib/librte_vhost/vhost_user.c
> @@ -406,6 +406,11 @@ vhost_user_set_vring_num(struct virtio_net **pdev,
>  	if (validate_msg_fds(msg, 0) != 0)
>  		return RTE_VHOST_MSG_RESULT_ERR;
> 
> +	if (msg->payload.state.num > 32768) {
> +		VHOST_LOG_CONFIG(ERR, "invalid virtqueue size %u\n", msg-
> >payload.state.num);
> +		return RTE_VHOST_MSG_RESULT_ERR;
> +	}
> +
>  	vq->size = msg->payload.state.num;
> 
>  	/* VIRTIO 1.0, 2.4 Virtqueues says:
> @@ -425,12 +430,6 @@ vhost_user_set_vring_num(struct virtio_net **pdev,
>  		}
>  	}
> 
> -	if (vq->size > 32768) {
> -		VHOST_LOG_CONFIG(ERR,
> -			"invalid virtqueue size %u\n", vq->size);
> -		return RTE_VHOST_MSG_RESULT_ERR;
> -	}
> -
>  	if (vq_is_packed(dev)) {
>  		if (vq->shadow_used_packed)
>  			rte_free(vq->shadow_used_packed);
> @@ -713,7 +712,7 @@ translate_ring_addresses(struct virtio_net *dev, int
> vq_index)
>  			return dev;
>  		}
> 
> -		vq->access_ok = 1;
> +		vq->access_ok = true;
>  		return dev;
>  	}
> 
> @@ -771,7 +770,7 @@ translate_ring_addresses(struct virtio_net *dev, int
> vq_index)
>  		vq->last_avail_idx = vq->used->idx;
>  	}
> 
> -	vq->access_ok = 1;
> +	vq->access_ok = true;
> 
>  	VHOST_LOG_CONFIG(DEBUG, "(%d) mapped address desc: %p\n",
>  			dev->vid, vq->desc);
> @@ -1658,7 +1657,7 @@ vhost_user_set_vring_call(struct virtio_net **pdev,
> struct VhostUserMsg *msg,
>  	vq = dev->virtqueue[file.index];
> 
>  	if (vq->ready) {
> -		vq->ready = 0;
> +		vq->ready = false;
>  		vhost_user_notify_queue_state(dev, file.index, 0);
>  	}
> 
> @@ -1918,14 +1917,14 @@ vhost_user_set_vring_kick(struct virtio_net **pdev,
> struct VhostUserMsg *msg,
>  	 * the SET_VRING_ENABLE message.
>  	 */
>  	if (!(dev->features & (1ULL << VHOST_USER_F_PROTOCOL_FEATURES))) {
> -		vq->enabled = 1;
> +		vq->enabled = true;
>  		if (dev->notify_ops->vring_state_changed)
>  			dev->notify_ops->vring_state_changed(
>  				dev->vid, file.index, 1);
>  	}
> 
>  	if (vq->ready) {
> -		vq->ready = 0;
> +		vq->ready = false;
>  		vhost_user_notify_queue_state(dev, file.index, 0);
>  	}
> 
> @@ -2043,7 +2042,7 @@ vhost_user_set_vring_enable(struct virtio_net **pdev,
>  			int main_fd __rte_unused)
>  {
>  	struct virtio_net *dev = *pdev;
> -	int enable = (int)msg->payload.state.num;
> +	bool enable = !!msg->payload.state.num;
>  	int index = (int)msg->payload.state.index;
> 
>  	if (validate_msg_fds(msg, 0) != 0)
> diff --git a/lib/librte_vhost/virtio_net.c b/lib/librte_vhost/virtio_net.c
> index 583bf379c6..3d8e29df09 100644
> --- a/lib/librte_vhost/virtio_net.c
> +++ b/lib/librte_vhost/virtio_net.c
> @@ -1396,13 +1396,13 @@ virtio_dev_rx(struct virtio_net *dev, uint16_t
> queue_id,
> 
>  	rte_spinlock_lock(&vq->access_lock);
> 
> -	if (unlikely(vq->enabled == 0))
> +	if (unlikely(!vq->enabled))
>  		goto out_access_unlock;
> 
>  	if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))
>  		vhost_user_iotlb_rd_lock(vq);
> 
> -	if (unlikely(vq->access_ok == 0))
> +	if (unlikely(!vq->access_ok))
>  		if (unlikely(vring_translate(dev, vq) < 0))
>  			goto out;
> 
> @@ -1753,13 +1753,13 @@ virtio_dev_rx_async_submit(struct virtio_net *dev,
> uint16_t queue_id,
> 
>  	rte_spinlock_lock(&vq->access_lock);
> 
> -	if (unlikely(vq->enabled == 0 || !vq->async_registered))
> +	if (unlikely(!vq->enabled || !vq->async_registered))
>  		goto out_access_unlock;
> 
>  	if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))
>  		vhost_user_iotlb_rd_lock(vq);
> 
> -	if (unlikely(vq->access_ok == 0))
> +	if (unlikely(!vq->access_ok))
>  		if (unlikely(vring_translate(dev, vq) < 0))
>  			goto out;
> 
> @@ -2518,7 +2518,7 @@ rte_vhost_dequeue_burst(int vid, uint16_t queue_id,
>  	if (unlikely(rte_spinlock_trylock(&vq->access_lock) == 0))
>  		return 0;
> 
> -	if (unlikely(vq->enabled == 0)) {
> +	if (unlikely(!vq->enabled)) {
>  		count = 0;
>  		goto out_access_unlock;
>  	}
> @@ -2526,7 +2526,7 @@ rte_vhost_dequeue_burst(int vid, uint16_t queue_id,
>  	if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))
>  		vhost_user_iotlb_rd_lock(vq);
> 
> -	if (unlikely(vq->access_ok == 0))
> +	if (unlikely(!vq->access_ok))
>  		if (unlikely(vring_translate(dev, vq) < 0)) {
>  			count = 0;
>  			goto out;
> --
> 2.30.2

Reviewed-by: Chenbo Xia <chenbo.xia at intel.com>