doc: add RCU guide

[dpdk.git] / doc / guides / nics / virtio.rst

diff --git a/doc/guides/nics/virtio.rst b/doc/guides/nics/virtio.rst
index 46e292c..2ae875c 100644 (file)
--- a/doc/guides/nics/virtio.rst
+++ b/doc/guides/nics/virtio.rst
@@ -47,7 +47,7 @@ In this release, the virtio PMD driver provides the basic functionality of packe
 *   The descriptor number for the Rx/Tx queue is hard-coded to be 256 by qemu 2.7 and below.
     If given a different descriptor number by the upper application,
     the virtio PMD generates a warning and fall back to the hard-coded value.
 *   The descriptor number for the Rx/Tx queue is hard-coded to be 256 by qemu 2.7 and below.
     If given a different descriptor number by the upper application,
     the virtio PMD generates a warning and fall back to the hard-coded value.

-    Rx queue size can be configureable and up to 1024 since qemu 2.8 and above. Rx queue size is 256
+    Rx queue size can be configurable and up to 1024 since qemu 2.8 and above. Rx queue size is 256

     by default. Tx queue size is still hard-coded to be 256.
 
 *   Features of mac/vlan filter are supported, negotiation with vhost/backend are needed to support them.
     by default. Tx queue size is still hard-coded to be 256.
 
 *   Features of mac/vlan filter are supported, negotiation with vhost/backend are needed to support them.


@@ -201,7 +201,7 @@ The packet transmission flow is:
 Virtio PMD Rx/Tx Callbacks
 --------------------------
 
 Virtio PMD Rx/Tx Callbacks
 --------------------------
 

-Virtio driver has 3 Rx callbacks and 2 Tx callbacks.
+Virtio driver has 4 Rx callbacks and 3 Tx callbacks.

 
 Rx callbacks:
 
 
 Rx callbacks:
 


@@ -215,6 +215,9 @@ Rx callbacks:
    Vector version without mergeable Rx buffer support, also fixes the available
    ring indexes and uses vector instructions to optimize performance.
 
    Vector version without mergeable Rx buffer support, also fixes the available
    ring indexes and uses vector instructions to optimize performance.
 

+#. ``virtio_recv_mergeable_pkts_inorder``:
+   In-order version with mergeable Rx buffer support.
+

 Tx callbacks:
 
 #. ``virtio_xmit_pkts``:
 Tx callbacks:
 
 #. ``virtio_xmit_pkts``:


@@ -223,6 +226,8 @@ Tx callbacks:
 #. ``virtio_xmit_pkts_simple``:
    Vector version fixes the available ring indexes to optimize performance.
 
 #. ``virtio_xmit_pkts_simple``:
    Vector version fixes the available ring indexes to optimize performance.
 

+#. ``virtio_xmit_pkts_inorder``:
+   In-order version.

 
 By default, the non-vector callbacks are used:
 
 
 By default, the non-vector callbacks are used:
 


@@ -254,6 +259,12 @@ Example of using the vector version of the virtio poll mode driver in
 
    testpmd -l 0-2 -n 4 -- -i --tx-offloads=0x0 --rxq=1 --txq=1 --nb-cores=1
 
 
    testpmd -l 0-2 -n 4 -- -i --tx-offloads=0x0 --rxq=1 --txq=1 --nb-cores=1
 

+In-order callbacks only work on simulated virtio user vdev.
+
+*   For Rx: If mergeable Rx buffers is enabled and in-order is enabled then
+    ``virtio_xmit_pkts_inorder`` is used.
+
+*   For Tx: If in-order is enabled then ``virtio_xmit_pkts_inorder`` is used.

 
 Interrupt mode
 --------------
 
 Interrupt mode
 --------------