INSTALL.DPDK: Add notes regarding vhost multiq configuration.

Linux kernel network devices in a guest should have the number of
multi-purpose channels configured when used with DPDK multiqueue on the host.
This commit adds an example of how this can be done. Also add QEMU 2.5
requirements for multiqueue with DPDK in NEWS.

Signed-off-by: Ian Stokes <ian.stokes@intel.com>
Acked-by: Flavio Leitner <fbl@sysclose.org>
Acked-by: Daniele Di Proietto <diproiettod@vmware.com>

INSTALL.DPDK.md

@@ -580,6 +580,22 @@ Follow the steps below to attach vhost-user port(s) to a VM.
    -device virtio-net-pci,mac=00:00:00:00:00:02,netdev=mynet2,mq=on,vectors=$v
    ```
 
+   If one wishes to use multiple queues for an interface in the guest, the
+   driver in the guest operating system must be configured to do so. It is
+   recommended that the number of queues configured be equal to '$q'.
+
+   For example, this can be done for the Linux kernel virtio-net driver with:
+
+   ```
+   ethtool -L <DEV> combined <$q>
+   ```
+
+   A note on the command above:
+
+   `-L`: Changes the numbers of channels of the specified network device
+
+   `combined`: Changes the number of multi-purpose channels.
+
 DPDK vhost-cuse:
 ----------------
 

NEWS

@@ -39,7 +39,7 @@ v2.5.0 - xx xxx xxxx
    - DPDK:
      * Requires DPDK 2.2
      * Added multiqueue support to vhost-user
-
+     * Note: QEMU 2.5+ required for multiqueue support
 
 v2.4.0 - 20 Aug 2015
 ---------------------