[dpdk-dev] [PATCH v2 2/2] vhost: improve batched copies performance
Maxime Coquelin
maxime.coquelin at redhat.com
Tue May 29 11:45:14 CEST 2018
Instead of copying batch_copy_nb_elems into the stack,
this patch uses it directly.
Small performance gain of 3% is seen when running PVP
benchmark.
Signed-off-by: Maxime Coquelin <maxime.coquelin at redhat.com>
---
lib/librte_vhost/virtio_net.c | 29 ++++++++++++++---------------
1 file changed, 14 insertions(+), 15 deletions(-)
diff --git a/lib/librte_vhost/virtio_net.c b/lib/librte_vhost/virtio_net.c
index e66b8f48a..98ad8e936 100644
--- a/lib/librte_vhost/virtio_net.c
+++ b/lib/librte_vhost/virtio_net.c
@@ -352,7 +352,6 @@ copy_mbuf_to_desc(struct virtio_net *dev, struct vhost_virtqueue *vq,
struct rte_mbuf *hdr_mbuf;
struct batch_copy_elem *batch_copy = vq->batch_copy_elems;
struct virtio_net_hdr_mrg_rxbuf tmp_hdr, *hdr = NULL;
- uint16_t copy_nb = vq->batch_copy_nb_elems;
int error = 0;
if (unlikely(m == NULL)) {
@@ -493,7 +492,8 @@ copy_mbuf_to_desc(struct virtio_net *dev, struct vhost_virtqueue *vq,
cpy_len = RTE_MIN(desc_chunck_len, mbuf_avail);
- if (likely(cpy_len > MAX_BATCH_LEN || copy_nb >= vq->size)) {
+ if (likely(cpy_len > MAX_BATCH_LEN ||
+ vq->batch_copy_nb_elems >= vq->size)) {
rte_memcpy((void *)((uintptr_t)(desc_addr +
desc_offset)),
rte_pktmbuf_mtod_offset(m, void *, mbuf_offset),
@@ -503,13 +503,14 @@ copy_mbuf_to_desc(struct virtio_net *dev, struct vhost_virtqueue *vq,
PRINT_PACKET(dev, (uintptr_t)(desc_addr + desc_offset),
cpy_len, 0);
} else {
- batch_copy[copy_nb].dst =
+ batch_copy[vq->batch_copy_nb_elems].dst =
(void *)((uintptr_t)(desc_addr + desc_offset));
- batch_copy[copy_nb].src =
+ batch_copy[vq->batch_copy_nb_elems].src =
rte_pktmbuf_mtod_offset(m, void *, mbuf_offset);
- batch_copy[copy_nb].log_addr = desc_gaddr + desc_offset;
- batch_copy[copy_nb].len = cpy_len;
- copy_nb++;
+ batch_copy[vq->batch_copy_nb_elems].log_addr =
+ desc_gaddr + desc_offset;
+ batch_copy[vq->batch_copy_nb_elems].len = cpy_len;
+ vq->batch_copy_nb_elems++;
}
mbuf_avail -= cpy_len;
@@ -520,7 +521,6 @@ copy_mbuf_to_desc(struct virtio_net *dev, struct vhost_virtqueue *vq,
}
out:
- vq->batch_copy_nb_elems = copy_nb;
return error;
}
@@ -766,7 +766,6 @@ copy_desc_to_mbuf(struct virtio_net *dev, struct vhost_virtqueue *vq,
/* A counter to avoid desc dead loop chain */
uint32_t nr_desc = 1;
struct batch_copy_elem *batch_copy = vq->batch_copy_elems;
- uint16_t copy_nb = vq->batch_copy_nb_elems;
int error = 0;
desc = &descs[desc_idx];
@@ -905,7 +904,7 @@ copy_desc_to_mbuf(struct virtio_net *dev, struct vhost_virtqueue *vq,
mbuf_avail = cpy_len;
} else {
if (likely(cpy_len > MAX_BATCH_LEN ||
- copy_nb >= vq->size ||
+ vq->batch_copy_nb_elems >= vq->size ||
(hdr && cur == m) ||
desc->len != desc_chunck_len)) {
rte_memcpy(rte_pktmbuf_mtod_offset(cur, void *,
@@ -914,14 +913,15 @@ copy_desc_to_mbuf(struct virtio_net *dev, struct vhost_virtqueue *vq,
desc_offset)),
cpy_len);
} else {
- batch_copy[copy_nb].dst =
+ batch_copy[vq->batch_copy_nb_elems].dst =
rte_pktmbuf_mtod_offset(cur, void *,
mbuf_offset);
- batch_copy[copy_nb].src =
+ batch_copy[vq->batch_copy_nb_elems].src =
(void *)((uintptr_t)(desc_addr +
desc_offset));
- batch_copy[copy_nb].len = cpy_len;
- copy_nb++;
+ batch_copy[vq->batch_copy_nb_elems].len =
+ cpy_len;
+ vq->batch_copy_nb_elems++;
}
}
@@ -1015,7 +1015,6 @@ copy_desc_to_mbuf(struct virtio_net *dev, struct vhost_virtqueue *vq,
vhost_dequeue_offload(hdr, m);
out:
- vq->batch_copy_nb_elems = copy_nb;
return error;
}
--
2.14.3
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