[dpdk-dev] [PATCH v1 1/2] net/virtio: restrict pointer aliasing for NEON vpmd

[Joyce Kong]

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 virtio-net PVP case, and a 2.4% perf improvement in throughput
for the virtio-user PVP case. All performance data are measured
under the 0.001% acceptable packet loss with 2 cores on the vhost
side.

Signed-off-by: Joyce Kong <joyce.kong at arm.com>
Reviewed-by: Phil Yang <phil.yang at arm.com>
---
 drivers/net/virtio/virtio_rxtx_simple_neon.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/virtio/virtio_rxtx_simple_neon.c b/drivers/net/virtio/virtio_rxtx_simple_neon.c
index 363e2b330..c08dd51fb 100644
--- a/drivers/net/virtio/virtio_rxtx_simple_neon.c
+++ b/drivers/net/virtio/virtio_rxtx_simple_neon.c
@@ -36,8 +36,8 @@
  * - nb_pkts < RTE_VIRTIO_DESC_PER_LOOP, just return no packet
  */
 uint16_t
-virtio_recv_pkts_vec(void *rx_queue, struct rte_mbuf **rx_pkts,
-	uint16_t nb_pkts)
+virtio_recv_pkts_vec(void *rx_queue, struct rte_mbuf
+		**__restrict rx_pkts, uint16_t nb_pkts)
 {
 	struct virtnet_rx *rxvq = rx_queue;
 	struct virtqueue *vq = rxvq->vq;
-- 
2.27.0