[dpdk-dev] [RFC] lib/librte_vhost: qemu vhost-user support into DPDK vhost library

Tetsuya.Mukawa mukawa at igel.co.jp
Wed Aug 27 08:07:43 CEST 2014

Hi Xie,

(2014/08/27 14:56), Xie, Huawei wrote:
> For virtio-net device driver, there is still no difference. Existing
> solution creates an eventfd module to install a fd in DPDK process
> pointing to the eventfd in qemu process. In vhost-user, the UNIX
> domain socket will do that work, create a new fd, install it in target
> DPDK server process, and make it point to the eventfd in qemu process. 
Thank you for explanation. I can understand clearly.


>> Anyway, about device creation and destruction, the difference will come
>> from transmission speed between unix domain socket and CUSE. I am not
>> sure which is faster.
>> Thanks,
>> Tetsuya
>>> Regards,
>>> Changchun
>>>> -----Original Message-----
>>>> From: Tetsuya.Mukawa [mailto:mukawa at igel.co.jp]
>>>> Sent: Wednesday, August 27, 2014 12:39 PM
>>>> To: Ouyang, Changchun; dev at dpdk.org
>>>> Cc: Xie, Huawei; Katsuya MATSUBARA; nakajima.yoshihiro at lab.ntt.co.jp;
>>>> Hitoshi Masutani
>>>> Subject: Re: [dpdk-dev] [RFC] lib/librte_vhost: qemu vhost-user support into
>>>> DPDK vhost library
>>>> (2014/08/27 9:43), Ouyang, Changchun wrote:
>>>>> Do we have performance comparison between both implementation?
>>>> Hi Changchun,
>>>> If DPDK applications are running on both guest and host side, the
>>>> performance should be almost same, because while transmitting data virt
>>>> queues are accessed by virtio-net PMD and libvhost. In libvhost, the existing
>>>> vhost implementation and a vhost-user implementation will shares or uses
>>>> same code to access virt queues. So I guess the performance will be almost
>>>> same.
>>>> Thanks,
>>>> Tetsuya
>>>>> Thanks
>>>>> Changchun
>>>>> -----Original Message-----
>>>>> From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Xie, Huawei
>>>>> Sent: Tuesday, August 26, 2014 7:06 PM
>>>>> To: dev at dpdk.org
>>>>> Subject: Re: [dpdk-dev] [RFC] lib/librte_vhost: qemu vhost-user
>>>>> support into DPDK vhost library
>>>>> Hi all:
>>>>> We are implementing qemu official vhost-user interface into DPDK vhost
>>>> library, so there would be two coexisting implementations for user space
>>>> vhost backend.
>>>>> Pro and cons in my mind:
>>>>> Existing solution:
>>>>> Pros:  works with qemu version before 2.1;  Cons: depends on eventfd
>>>> proxy kernel module and extra maintenance effort Qemu vhost-user:
>>>>>                Pros:  qemu official us-vhost interface;     Cons: only available after
>>>> qemu 2.1
>>>>> BR.
>>>>> huawei

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