[dpdk-dev] [PATCH v2 3/3] net/virtio: improve batching in mergeable path
Jens Freimann
jfreimann at redhat.com
Wed Dec 19 10:47:43 CET 2018
On Tue, Dec 11, 2018 at 02:48:04PM +0100, Maxime Coquelin wrote:
>This patch improves both descriptors dequeue and refill,
>by using the same bathing strategy as done in in-order path.
s/bathing/batching/
>
>Signed-off-by: Maxime Coquelin <maxime.coquelin at redhat.com>
>---
> drivers/net/virtio/virtio_rxtx.c | 237 ++++++++++++++++---------------
> 1 file changed, 126 insertions(+), 111 deletions(-)
>
>diff --git a/drivers/net/virtio/virtio_rxtx.c b/drivers/net/virtio/virtio_rxtx.c
>index ebe5c74b5..59bcac2f7 100644
>--- a/drivers/net/virtio/virtio_rxtx.c
>+++ b/drivers/net/virtio/virtio_rxtx.c
>@@ -267,41 +267,42 @@ virtqueue_enqueue_refill_inorder(struct virtqueue *vq,
> }
>
> static inline int
>-virtqueue_enqueue_recv_refill(struct virtqueue *vq, struct rte_mbuf *cookie)
>+virtqueue_enqueue_recv_refill(struct virtqueue *vq, struct rte_mbuf **cookie,
>+ uint16_t num)
> {
> struct vq_desc_extra *dxp;
> struct virtio_hw *hw = vq->hw;
>- struct vring_desc *start_dp;
>- uint16_t needed = 1;
>- uint16_t head_idx, idx;
>+ struct vring_desc *start_dp = vq->vq_ring.desc;
>+ uint16_t idx, i;
>
> if (unlikely(vq->vq_free_cnt == 0))
> return -ENOSPC;
>- if (unlikely(vq->vq_free_cnt < needed))
>+ if (unlikely(vq->vq_free_cnt < num))
> return -EMSGSIZE;
>
>- head_idx = vq->vq_desc_head_idx;
>- if (unlikely(head_idx >= vq->vq_nentries))
>+ if (unlikely(vq->vq_desc_head_idx >= vq->vq_nentries))
> return -EFAULT;
>
>- idx = head_idx;
>- dxp = &vq->vq_descx[idx];
>- dxp->cookie = (void *)cookie;
>- dxp->ndescs = needed;
>+ for (i = 0; i < num; i++) {
>+ idx = vq->vq_desc_head_idx;
>+ dxp = &vq->vq_descx[idx];
>+ dxp->cookie = (void *)cookie[i];
I think code is safe as it is, but should we check if cookie actually points to something?
I tested this patch and saw the same performance improvement, so
Tested-by: Jens Freimann <jfreimann at redhat.com>
Reviewed-by: Jens Freimann <jfreimann at redhat.com>
regards,
Jens
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