Restrict pointer aliasing to allow the compiler to vectorize
loops 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
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>
---
lib/librte_vhost/virtio_net.c | 14 +++++++-------
1 file changed, 7 insertions(+), 7 deletions(-)
diff --git a/lib/librte_vhost/virtio_net.c b/lib/librte_vhost/virtio_net.c
index 751c1f373..39c92e7e1 100644
--- a/lib/librte_vhost/virtio_net.c
+++ b/lib/librte_vhost/virtio_net.c
@@ -1133,8 +1133,8 @@ 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 *__restrict vq,
+ struct rte_mbuf **__restrict pkts,
uint32_t count)
{
uint32_t pkt_idx = 0;
@@ -1219,7 +1219,7 @@ 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 **__restrict pkts, uint16_t count)
{
struct virtio_net *dev = get_device(vid);
@@ -2124,9 +2124,9 @@ 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 *__restrict vq,
struct rte_mempool *mbuf_pool,
- struct rte_mbuf **pkts,
+ struct rte_mbuf **__restrict pkts,
uint32_t count)
{
uint32_t pkt_idx = 0;
@@ -2160,9 +2160,9 @@ 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 *__restrict vq,
struct rte_mempool *mbuf_pool,
- struct rte_mbuf **pkts,
+ struct rte_mbuf **__restrict pkts,
uint32_t count)
{
uint32_t pkt_idx = 0;
--
2.27.0
