X-Git-Url: http://git.droids-corp.org/?a=blobdiff_plain;f=doc%2Fguides%2Fnics%2Fnetvsc.rst;h=19f9940fe6e1ba80815632302041f271f4593012;hb=a124f9e9591bf2b22b20e2d117775b0ff0b9f684;hp=345f393c24ba6b3f64de76d75ccb8434359aef7e;hpb=4b048f352c0126f6f7b8ab36e6ad7bb33703ceac;p=dpdk.git

diff --git a/doc/guides/nics/netvsc.rst b/doc/guides/nics/netvsc.rst
index 345f393c24..19f9940fe6 100644
--- a/doc/guides/nics/netvsc.rst
+++ b/doc/guides/nics/netvsc.rst
@@ -28,19 +28,16 @@ In this release, the hyper PMD driver provides the basic functionality of packet
 
 *   VLAN tags are always stripped and presented in mbuf tci field.
 
-*   The Hyper-V driver does not use or support Link State or Rx interrupt.
+*   The Hyper-V driver does not use or support interrupts. Link state change
+    callback is done via change events in the packet ring.
 
 *   The maximum number of queues is limited by the host (currently 64).
     When used with 4.16 kernel only a single queue is available.
 
-.. note::
-   This driver is intended for use with **Hyper-V only** and is
-   not recommended for use on Azure because accelerated Networking
-   (SR-IOV) is not supported.
-
-   On Azure, use the :doc:`vdev_netvsc` which
-   automatically configures the necessary TAP and failsave drivers.
-
+*   This driver supports SR-IOV network acceleration.
+    If SR-IOV is enabled then the driver will transparently manage the interface,
+    and send and receive packets using the VF path.
+    The VDEV_NETVSC and FAILSAFE drivers are *not* used when using netvsc PMD.
 
 Installation
 ------------
@@ -92,7 +89,7 @@ operations:
 
 .. Note::
 
-   The dpkd-devbind.py script can not be used since it only handles PCI devices.
+   The dpdk-devbind.py script can not be used since it only handles PCI devices.
 
 
 Prerequisites
@@ -103,3 +100,44 @@ The following prerequisites apply:
 *   Linux kernel support for UIO on vmbus is done with the uio_hv_generic driver.
     Full support of multiple queues requires the 4.17 kernel. It is possible
     to use the netvsc PMD with 4.16 kernel but it is limited to a single queue.
+
+
+Netvsc PMD arguments
+--------------------
+
+The user can specify below argument in devargs.
+
+#.  ``latency``:
+
+    A netvsc device uses a mailbox page to indicate to the host that there
+    is something in the transmit queue. The host scans this page at a
+    periodic interval. This parameter allows adjusting the value that
+    is used by the host. Smaller values improve transmit latency, and larger
+    values save CPU cycles. This parameter is in microseconds.
+    If the value is too large or too small it will be
+    ignored by the host. (Default: 50)
+
+#.  ``rx_copybreak``:
+
+    The rx_copybreak sets the threshold where the driver uses an external
+    mbuf to avoid having to copy data. Setting 0 for copybreak will cause
+    driver to always create an external mbuf. Setting a value greater than
+    the MTU would prevent it from ever making an external mbuf and always
+    copy. The default value is 256 (bytes).
+
+#.  ``tx_copybreak``:
+
+    The tx_copybreak sets the threshold where the driver aggregates
+    multiple small packets into one request. If tx_copybreak is 0 then
+    each packet goes as a VMBus request (no copying). If tx_copybreak is
+    set larger than the MTU, then all packets smaller than the chunk size
+    of the VMBus send buffer will be copied; larger packets always have to
+    go as a single direct request. The default value is 512 (bytes).
+
+#.  ``rx_extmbuf_enable``:
+    The rx_extmbuf_enable is used to control if netvsc should use external
+    mbuf for receiving packets. The default value is 0. (netvsc doesn't use
+    external mbuf, it always allocates mbuf and copy received data to mbuf)
+    A non-zero value tells netvsc to attach external buffers to mbuf on
+    receiving packets, thus avoid copying memory. Use of external buffers
+    requires the application is able to read data from external mbuf.