Restrict pointer aliasing to allow the compiler to vectorize loop
more aggressively.
With this patch, a 9.6% improvement is observed in throughput for
the packed virtio-net PVP case, and a 2.8% improvement in throughput
for the packed virtio-user PVP case. All performance data are measured
on ThunderX-2 platform under 0.001% acceptable packet loss with 1 core
on both vhost and virtio side.
Signed-off-by: Joyce Kong <joyce.k...@arm.com>
Reviewed-by: Phil Yang <phil.y...@arm.com>
---
drivers/net/virtio/virtio_rxtx_simple_neon.c | 5 +++--
lib/librte_vhost/virtio_net.c | 14 +++++++-------
2 files changed, 10 insertions(+), 9 deletions(-)
diff --git a/drivers/net/virtio/virtio_rxtx_simple_neon.c
b/drivers/net/virtio/virtio_rxtx_simple_neon.c
index a9b649814..02520fda8 100644
--- a/drivers/net/virtio/virtio_rxtx_simple_neon.c
+++ b/drivers/net/virtio/virtio_rxtx_simple_neon.c
@@ -36,8 +36,9 @@
* - nb_pkts < RTE_VIRTIO_DESC_PER_LOOP, just return no packet
*/
uint16_t
-virtio_recv_pkts_vec(void *rx_queue, struct rte_mbuf
- **__rte_restrict rx_pkts, uint16_t nb_pkts)
+virtio_recv_pkts_vec(void *rx_queue,
+ struct rte_mbuf **__rte_restrict rx_pkts,
+ uint16_t nb_pkts)
{
struct virtnet_rx *rxvq = rx_queue;
struct virtqueue *vq = rxvq->vq;
diff --git a/lib/librte_vhost/virtio_net.c b/lib/librte_vhost/virtio_net.c
index 236498f71..1d0be3dd4 100644
--- a/lib/librte_vhost/virtio_net.c
+++ b/lib/librte_vhost/virtio_net.c
@@ -1353,8 +1353,8 @@ virtio_dev_rx_single_packed(struct virtio_net *dev,
static __rte_noinline uint32_t
virtio_dev_rx_packed(struct virtio_net *dev,
- struct vhost_virtqueue *vq,
- struct rte_mbuf **pkts,
+ struct vhost_virtqueue *__rte_restrict vq,
+ struct rte_mbuf **__rte_restrict pkts,
uint32_t count)
{
uint32_t pkt_idx = 0;
@@ -1439,7 +1439,7 @@ virtio_dev_rx(struct virtio_net *dev, uint16_t queue_id,
uint16_t
rte_vhost_enqueue_burst(int vid, uint16_t queue_id,
- struct rte_mbuf **pkts, uint16_t count)
+ struct rte_mbuf **__rte_restrict pkts, uint16_t count)
{
struct virtio_net *dev = get_device(vid);
@@ -2671,9 +2671,9 @@ free_zmbuf(struct vhost_virtqueue *vq)
static __rte_noinline uint16_t
virtio_dev_tx_packed_zmbuf(struct virtio_net *dev,
- struct vhost_virtqueue *vq,
+ struct vhost_virtqueue *__rte_restrict vq,
struct rte_mempool *mbuf_pool,
- struct rte_mbuf **pkts,
+ struct rte_mbuf **__rte_restrict pkts,
uint32_t count)
{
uint32_t pkt_idx = 0;
@@ -2707,9 +2707,9 @@ virtio_dev_tx_packed_zmbuf(struct virtio_net *dev,
static __rte_noinline uint16_t
virtio_dev_tx_packed(struct virtio_net *dev,
- struct vhost_virtqueue *vq,
+ struct vhost_virtqueue *__rte_restrict vq,
struct rte_mempool *mbuf_pool,
- struct rte_mbuf **pkts,
+ struct rte_mbuf **__rte_restrict pkts,
uint32_t count)
{
uint32_t pkt_idx = 0;
--
2.27.0
