dpdk patch: virtio: tx with can_push when VERSION_1 is set

This patch for dpdk 16.11 enables the use of shallow
virtio descriptors when VERSION_1 is set.

More info on DPDK patchwork:
  http://dpdk.org/dev/patchwork/patch/17340/

Change-Id: I28cde77ed5a3588921d00da50678debfe0338b08
Signed-off-by: Pierre Pfister <ppfister@cisco.com>

diff --git a/dpdk/dpdk-16.11_patches/0001-virtio-tx-with-can_push-when-VERSION_1-is-set.patch b/dpdk/dpdk-16.11_patches/0001-virtio-tx-with-can_push-when-VERSION_1-is-set.patch
new file mode 100644 (file)
index 0000000..c269356
--- /dev/null
+++ b/dpdk/dpdk-16.11_patches/0001-virtio-tx-with-can_push-when-VERSION_1-is-set.patch
@@ -0,0 +1,38 @@
+From b002b56c0c8a1790549c23d93f3d57ffc212c6da Mon Sep 17 00:00:00 2001
+From: Pierre Pfister <ppfister@cisco.com>
+Date: Tue, 8 Nov 2016 10:24:48 +0100
+Subject: [PATCH] virtio: tx with can_push when VERSION_1 is set
+
+Current virtio driver advertises VERSION_1 support,
+but does not handle device's VERSION_1 support when
+sending packets (it looks for ANY_LAYOUT feature,
+which is absent).
+
+This patch enables 'can_push' in tx path when VERSION_1
+is advertised by the device.
+
+This significantly improves small packets forwarding rate
+towards devices advertising VERSION_1 feature.
+
+Signed-off-by: Pierre Pfister <ppfister@cisco.com>
+---
+ drivers/net/virtio/virtio_rxtx.c | 3 ++-
+ 1 file changed, 2 insertions(+), 1 deletion(-)
+
+diff --git a/drivers/net/virtio/virtio_rxtx.c b/drivers/net/virtio/virtio_rxtx.c
+index 22d97a4..1e5a6b9 100644
+--- a/drivers/net/virtio/virtio_rxtx.c
++++ b/drivers/net/virtio/virtio_rxtx.c
+@@ -1015,7 +1015,8 @@ virtio_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts, uint16_t nb_pkts)
+               }
+ 
+               /* optimize ring usage */
+-              if (vtpci_with_feature(hw, VIRTIO_F_ANY_LAYOUT) &&
++              if ((vtpci_with_feature(hw, VIRTIO_F_ANY_LAYOUT) ||
++                    vtpci_with_feature(hw, VIRTIO_F_VERSION_1)) &&
+                   rte_mbuf_refcnt_read(txm) == 1 &&
+                   RTE_MBUF_DIRECT(txm) &&
+                   txm->nb_segs == 1 &&
+-- 
+2.7.4 (Apple Git-66)
+