[dpdk-users] VIRTIO for containers

王志克 wangzhike at jd.com
Fri Oct 20 11:24:55 CEST 2017


I read this thread, and try to do the same way (legacy containers connect to ovs+dpdk). However, I meet following error when creating ovs port.

ovs-vsctl add-port br0 virtiouser0 -- set Interface virtiouser0 type=dpdk options:dpdk-devargs=net_virtio_user0,path=/dev/vhost-net
ovs-vsctl: Error detected while setting up 'virtiouser0': Error attaching device 'net_virtio_user0,path=/dev/vhost-net' to DPDK.  See ovs-vswitchd log for details.
ovs-vsctl: The default log directory is "/var/log/openvswitch".

Debug shows that it calls virtio_user_dev_init()->vhost_user_setup(), and failed in connect() with target /dev/vhost-net. The errno is ECONNREFUSED.
Below command indeed shows no one is listening.
lsof | grep vhost-net

In kernel OVS, I guess qemu-kvm would listne to /dev/vhost-net. But for ovs_dpdk and container, what extra work need be done? Appreciate any help.

Br,
Wang Zhike



> -----Original Message-----

> From: Avi Cohen (A) [mailto:avi.cohen at huawei.com<http://dpdk.org/ml/listinfo/users>]

> Sent: Sunday, July 9, 2017 11:32 PM

> To: Tan, Jianfeng; dpdk-ovs at lists.01.org<http://dpdk.org/ml/listinfo/users>; users at dpdk.org<http://dpdk.org/ml/listinfo/users>

> Subject: RE: VIRTIO for containers

>

> Thanks you Jianfeng - pls see inline marked  [Avi Cohen (A)]

>

> > -----Original Message-----

> > From: Tan, Jianfeng [mailto:jianfeng.tan at intel.com<http://dpdk.org/ml/listinfo/users>]

> > Sent: Monday, 03 July, 2017 10:22 AM

> > To: Avi Cohen (A); dpdk-ovs at lists.01.org<http://dpdk.org/ml/listinfo/users>; users at dpdk.org<http://dpdk.org/ml/listinfo/users>

> > Subject: RE: VIRTIO for containers

> >

> >

> >

> > > -----Original Message-----

> > > From: Avi Cohen (A) [mailto:avi.cohen at huawei.com<http://dpdk.org/ml/listinfo/users>]

> > > Sent: Wednesday, June 28, 2017 2:45 PM

> > > To: Tan, Jianfeng; dpdk-ovs at lists.01.org<http://dpdk.org/ml/listinfo/users>; users at dpdk.org<http://dpdk.org/ml/listinfo/users>

> > > Subject: RE: VIRTIO for containers

> > >

> > > Thank you Jianfeng

> > >

> > > > -----Original Message-----

> > > > From: Tan, Jianfeng [mailto:jianfeng.tan at intel.com<http://dpdk.org/ml/listinfo/users>]

> > > > Sent: Tuesday, 27 June, 2017 5:22 PM

> > > > To: Avi Cohen (A); dpdk-ovs at lists.01.org<http://dpdk.org/ml/listinfo/users>; users at dpdk.org<http://dpdk.org/ml/listinfo/users>

> > > > Subject: Re: VIRTIO for containers

> > > >

> > > >

> > > >

> > > > On 6/26/2017 8:06 PM, Avi Cohen (A) wrote:

> > > > > Thank You Jianfeng

> > > > >

> > > > >> We have developed virtio-user + vhost-kernel as the backend. In

> > > > >> that scenario, you can add the tap interface into a container

> > > > >> network

> > > > namespace.

> > > > >> And there's a vhost kthread to push the data out to user space.

> > > > >>

> > > > >> And I cannot guarantee the performance as it has diametric model

> > > > >> in VM

> > > > >> (virtio) - OVS-DPDK (vhost).

> > > > >>

> > > > > [Avi Cohen (A)]

> > > > > Can you refer to a document how to run this setup?

> > > >

> > > > Please refer to

> > > >

> http://dpdk.org/doc/guides/howto/virtio_user_as_exceptional_path.htm

> > > > l

> > > >

> > > [Avi Cohen (A)]

> > > My setup includes a container and ovs-dpdk , i still not sure about:

> > >  - How to set the virtio backend port in the ovs-dpdk ?

> >

> > For OVS-DPDK, you need a version above 2.7.0. Below command is used to

> > create a virtio-user port with vhost-kernel backend:

> > # ovs-vsctl add-port br0 virtiouser0 -- set Interface virtiouser0 type=dpdk

> > options:dpdk-devargs=virtio_user0,path=/dev/vhost-net

> >

> > >  - How to set the container with the virtio frontend ?

> >

> > No, containers will not hold the virtio frontend in this case. Above ovs-vsctl

> > command will generate a virtio-user port in OVS, and a tap interface in

> > kernel, you can assign the tap interface into a net namespace of some

> > container so that its networking flow will go through OVS-DPDK then to

> > outside.

> [Avi Cohen (A)]

> Thanks you Jianfeng

> I've tested it and the performance looks very good compared to native ovs.

> I have 1 more question:

> You wrote " there's a vhost kthread to push the data out to user space " -

> Is that mean a copy from userspace to kernel (and viceversa) or there is a

> zero-copy mmap  like in AF_PACKET which handles TX/RX rings in userspace ?

> Best Regards

> avi



So far it needs data copy at least from kernel to user path; there's an experimental feature, named experimental_zcopytx, to avoid data copy, but not very useful due to the implementation limitation.



Packet mmap (similar to AF_PACKET) is exactly the direction we were discussing for the further optimization. Plus, an optimized vhost thread model (current thread model is: one thread for one rx-tx queue pair) is also considered.



Thanks,

Jianfeng



> >

> > Thanks,

> > Jianfeng

> >

> > > Best Regards

> > > avi

> > >

> > > > Thanks,

> > > > Jianfeng

> > > >

> > > > > Best Regards

> > > > > avi

> > > > >>> I've tested the performance of a container connected to OVS-

> DPDK

> > > > >>> via vdev-af_packet  and processed by virtual PMD, and its

> > > > >>> performance is good [uses mmap'ed to userspace  - zero copy

> > > > >>> RX/TX ring buffer] but not good as  the performance  of a  VM

> > > > >>> connected to OVS-DPDK (@host) via vhost-user virtio.

> > > > >>> Best Regards

> > > > >>> avi

> > > > >>>

> > > > >>>> -----Original Message-----

> > > > >>>> From: Tan, Jianfeng [mailto:jianfeng.tan at intel.com<http://dpdk.org/ml/listinfo/users>]

> > > > >>>> Sent: Monday, 26 June, 2017 6:15 AM

> > > > >>>> To: Avi Cohen (A); dpdk-ovs at lists.01.org<http://dpdk.org/ml/listinfo/users>; users at dpdk.org<http://dpdk.org/ml/listinfo/users>

> > > > >>>> Subject: RE: VIRTIO for containers

> > > > >>>>

> > > > >>>> Hi Avi,

> > > > >>>>

> > > > >>>>> -----Original Message-----

> > > > >>>>> From: users [mailto:users-bounces at dpdk.org<http://dpdk.org/ml/listinfo/users>] On Behalf Of Avi

> > > Cohen

> > > > >>>>> (A)

> > > > >>>>> Sent: Sunday, June 25, 2017 11:13 PM

> > > > >>>>> To: dpdk-ovs at lists.01.org<http://dpdk.org/ml/listinfo/users>; users at dpdk.org<http://dpdk.org/ml/listinfo/users>

> > > > >>>>> Subject: [dpdk-users] VIRTIO for containers

> > > > >>>>>

> > > > >>>>> Hello,

> > > > >>>>> Does  anyone know the status of this project

> > > > >>>>> http://dpdk.org/ml/archives/dev/2015-November/027732.html

> -

> > > > >>>>> Implementing a virtio device for containers ?

> > > > >>>> It has been upstreamed since v16.07. Here is a howto doc:

> > > > >>>>

> > > > >>>

> > > >

> > http://dpdk.org/doc/guides/howto/virtio_user_for_container_networking.

> > > > >>> h

> > > > >>>> tml

> > > > >>>>

> > > > >>>>

> > > > >>>> Thanks,

> > > > >>>> Jianfeng

> > > > >>>>

> > > > >>>>> Best Regards

> > > > >>>>> avi



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