virtio: add packet buffering on tx
Type: feature
This patch adds packet buffering on tx for
slow backend which have some jitter/delays
in freeing the vrings.
There are some limitations to the current design:
1) It only works in poll mode.
2) Atleast 1 rx queue of an interface (with buffering
enabled) should be placed on each worker and main thread.
Signed-off-by: Mohsin Kazmi <sykazmi@cisco.com>
Change-Id: Ib93c350298b228e80426e58ac77f3bbc93b8be27
diff --git a/src/vnet/devices/virtio/virtio.c b/src/vnet/devices/virtio/virtio.c
index e74f378..8209a46 100644
--- a/src/vnet/devices/virtio/virtio.c
+++ b/src/vnet/devices/virtio/virtio.c
@@ -216,6 +216,7 @@
clib_mem_free (vring->avail);
vec_free (vring->buffers);
gro_flow_table_free (vring->flow_table);
+ virtio_vring_buffering_free (vm, vring->buffering);
clib_spinlock_free (&vring->lockp);
return 0;
}
@@ -235,6 +236,28 @@
}
}
+clib_error_t *
+virtio_set_packet_buffering (virtio_if_t * vif, u16 buffering_size)
+{
+ vnet_main_t *vnm = vnet_get_main ();
+ vnet_hw_interface_t *hw = vnet_get_hw_interface (vnm, vif->hw_if_index);
+ virtio_vring_t *vring;
+ clib_error_t *error = 0;
+ vif->packet_buffering = 1;
+
+ vec_foreach (vring, vif->txq_vrings)
+ {
+ if ((error =
+ virtio_vring_buffering_init (&vring->buffering, hw->tx_node_index,
+ buffering_size)))
+ {
+ break;
+ }
+ }
+
+ return error;
+}
+
void
virtio_vring_set_numa_node (vlib_main_t * vm, virtio_if_t * vif, u32 idx)
{
@@ -335,6 +358,7 @@
vlib_cli_output (vm, " gso-enabled %d", vif->gso_enabled);
vlib_cli_output (vm, " csum-enabled %d", vif->csum_offload_enabled);
vlib_cli_output (vm, " packet-coalesce %d", vif->packet_coalesce);
+ vlib_cli_output (vm, " packet-buffering %d", vif->packet_buffering);
if (type & (VIRTIO_IF_TYPE_TAP | VIRTIO_IF_TYPE_PCI))
vlib_cli_output (vm, " Mac Address: %U", format_ethernet_address,
vif->mac_addr);
@@ -432,6 +456,11 @@
vlib_cli_output (vm, " %U", gro_flow_table_format,
vring->flow_table);
}
+ if (vif->packet_buffering)
+ {
+ vlib_cli_output (vm, " %U", virtio_vring_buffering_format,
+ vring->buffering);
+ }
if (show_descr)
{
vlib_cli_output (vm, "\n descriptor table:\n");