X-Git-Url: https://gerrit.fd.io/r/gitweb?a=blobdiff_plain;f=drivers%2Fnet%2Fvirtio%2Fvirtio_rxtx.c;h=a33ef1a88ecdcef1c2342c307ff829383154614f;hb=0c3ed7dcda2b9a08702cd5e30d8e48f412ad62fd;hp=22d97a4ea5b3e447a27d3488754ed43eb7ee5d11;hpb=d4326699b9ff4788aed0c889a5c26a840e75a352;p=deb_dpdk.git

diff --git a/drivers/net/virtio/virtio_rxtx.c b/drivers/net/virtio/virtio_rxtx.c
index 22d97a4e..a33ef1a8 100644
--- a/drivers/net/virtio/virtio_rxtx.c
+++ b/drivers/net/virtio/virtio_rxtx.c
@@ -258,6 +258,12 @@ tx_offload_enabled(struct virtio_hw *hw)
 		vtpci_with_feature(hw, VIRTIO_NET_F_HOST_TSO6);
 }
 
+/* avoid write operation when necessary, to lessen cache issues */
+#define ASSIGN_UNLESS_EQUAL(var, val) do {	\
+	if ((var) != (val))			\
+		(var) = (val);			\
+} while (0)
+
 static inline void
 virtqueue_enqueue_xmit(struct virtnet_tx *txvq, struct rte_mbuf *cookie,
 		       uint16_t needed, int use_indirect, int can_push)
@@ -286,8 +292,14 @@ virtqueue_enqueue_xmit(struct virtnet_tx *txvq, struct rte_mbuf *cookie,
 		hdr = (struct virtio_net_hdr *)
 			rte_pktmbuf_prepend(cookie, head_size);
 		/* if offload disabled, it is not zeroed below, do it now */
-		if (offload == 0)
-			memset(hdr, 0, head_size);
+		if (offload == 0) {
+			ASSIGN_UNLESS_EQUAL(hdr->csum_start, 0);
+			ASSIGN_UNLESS_EQUAL(hdr->csum_offset, 0);
+			ASSIGN_UNLESS_EQUAL(hdr->flags, 0);
+			ASSIGN_UNLESS_EQUAL(hdr->gso_type, 0);
+			ASSIGN_UNLESS_EQUAL(hdr->gso_size, 0);
+			ASSIGN_UNLESS_EQUAL(hdr->hdr_len, 0);
+		}
 	} else if (use_indirect) {
 		/* setup tx ring slot to point to indirect
 		 * descriptor list stored in reserved region.
@@ -337,9 +349,9 @@ virtqueue_enqueue_xmit(struct virtnet_tx *txvq, struct rte_mbuf *cookie,
 			break;
 
 		default:
-			hdr->csum_start = 0;
-			hdr->csum_offset = 0;
-			hdr->flags = 0;
+			ASSIGN_UNLESS_EQUAL(hdr->csum_start, 0);
+			ASSIGN_UNLESS_EQUAL(hdr->csum_offset, 0);
+			ASSIGN_UNLESS_EQUAL(hdr->flags, 0);
 			break;
 		}
 
@@ -355,9 +367,9 @@ virtqueue_enqueue_xmit(struct virtnet_tx *txvq, struct rte_mbuf *cookie,
 				cookie->l3_len +
 				cookie->l4_len;
 		} else {
-			hdr->gso_type = 0;
-			hdr->gso_size = 0;
-			hdr->hdr_len = 0;
+			ASSIGN_UNLESS_EQUAL(hdr->gso_type, 0);
+			ASSIGN_UNLESS_EQUAL(hdr->gso_size, 0);
+			ASSIGN_UNLESS_EQUAL(hdr->hdr_len, 0);
 		}
 	}