From 8b25d1ad5d2264bdfc2818c7bda74ee2697df6db Mon Sep 17 00:00:00 2001 From: Christian Ehrhardt Date: Wed, 6 Jul 2016 09:22:35 +0200 Subject: Imported Upstream version 16.07-rc1 Change-Id: I40a523e52f12e8496fdd69e902824b0226c303de Signed-off-by: Christian Ehrhardt --- doc/guides/sample_app_ug/vhost.rst | 53 ++++++++++++++------------------------ 1 file changed, 20 insertions(+), 33 deletions(-) (limited to 'doc/guides/sample_app_ug/vhost.rst') diff --git a/doc/guides/sample_app_ug/vhost.rst b/doc/guides/sample_app_ug/vhost.rst index 47ce36ce..a93e54d8 100644 --- a/doc/guides/sample_app_ug/vhost.rst +++ b/doc/guides/sample_app_ug/vhost.rst @@ -491,39 +491,9 @@ The default value is 15. -- --rx-retry 1 --rx-retry-delay 20 **Zero copy.** -The zero copy option enables/disables the zero copy mode for RX/TX packet, -in the zero copy mode the packet buffer address from guest translate into host physical address -and then set directly as DMA address. -If the zero copy mode is disabled, then one copy mode is utilized in the sample. -This option is disabled by default. - -.. code-block:: console - - ./vhost-switch -c f -n 4 --socket-mem 1024 --huge-dir /mnt/huge \ - -- --zero-copy [0,1] - -**RX descriptor number.** -The RX descriptor number option specify the Ethernet RX descriptor number, -Linux legacy virtio-net has different behavior in how to use the vring descriptor from DPDK based virtio-net PMD, -the former likely allocate half for virtio header, another half for frame buffer, -while the latter allocate all for frame buffer, -this lead to different number for available frame buffer in vring, -and then lead to different Ethernet RX descriptor number could be used in zero copy mode. -So it is valid only in zero copy mode is enabled. The value is 32 by default. - -.. code-block:: console - - ./vhost-switch -c f -n 4 --socket-mem 1024 --huge-dir /mnt/huge \ - -- --zero-copy 1 --rx-desc-num [0, n] - -**TX descriptor number.** -The TX descriptor number option specify the Ethernet TX descriptor number, it is valid only in zero copy mode is enabled. -The value is 64 by default. - -.. code-block:: console - - ./vhost-switch -c f -n 4 --socket-mem 1024 --huge-dir /mnt/huge \ - -- --zero-copy 1 --tx-desc-num [0, n] +Zero copy mode is removed, due to it has not been working for a while. And +due to the large and complex code, it's better to redesign it than fixing +it to make it work again. Hence, zero copy may be added back later. **VLAN strip.** The VLAN strip option enable/disable the VLAN strip on host, if disabled, the guest will receive the packets with VLAN tag. @@ -863,3 +833,20 @@ For example: The above message indicates that device 0 has been registered with MAC address cc:bb:bb:bb:bb:bb and VLAN tag 1000. Any packets received on the NIC with these values is placed on the devices receive queue. When a virtio-net device transmits packets, the VLAN tag is added to the packet by the DPDK vhost sample code. + +Running virtio-user with vhost-switch +------------------------------------- + +We can also use virtio-user with vhost-switch now. +Virtio-user is a virtual device that can be run in a application (container) parallelly with vhost in the same OS, +aka, there is no need to start a VM. We just run it with a different --file-prefix to avoid startup failure. + +.. code-block:: console + + cd ${RTE_SDK}/x86_64-native-linuxapp-gcc/app + ./testpmd -c 0x3 -n 4 --socket-mem 1024 --no-pci --file-prefix=virtio-user-testpmd \ + --vdev=virtio-user0,mac=00:01:02:03:04:05,path=$path_vhost \ + -- -i --txqflags=0xf01 --disable-hw-vlan + +There is no difference on the vhost side. +Pleae note that there are some limitations (see release note for more information) in the usage of virtio-user. -- cgit 1.2.3-korg