[dpdk-users] Why kickfd from qemu is zero in qemu-dpdk vhost-user architecture?

Li Feng fengli at smartx.com
Sun Jul 15 15:21:18 CEST 2018
Previous message: [dpdk-users] Why kickfd from qemu is zero in qemu-dpdk vhost-user architecture?
Next message: [dpdk-users] Problem profiling DPDK
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]
I did understand what you mean.

I'm familiar with vhost-user about storage.

I mean you could check the `errno`.



Thanks,

Feng Li



手机：13401157876

Web：http://www.smartx.com/

地址：北京市海淀区科学院南路2号融科资讯中心C座北楼712

2018-07-15 18:16 GMT+08:00 杨晔 <yangye at ict.ac.cn>:

> Oh, I forgot to say that eventfd_read returns -1.
>
> But I don't think you understand what I mean.
>
> In vhost-user architecture. Backend(ovs-dpdk) communicates with
> fronted(qemu) through two virtqueues by default.
>
> Every queue has a pair of eventfd.
>
> Kickfd is written by backend to notify frontend to process packets. And in
> dpdk's code, it will write these kickfds when enque or dequeue is finished.
>
> Callfd is written by frontend to notify backend to process packets. But
> dpdk uses polling mode and don't check these callfds.
>
> Now I just want to use these callfd written by frontend to notify in my
> modified version.
>
> Here is the question. That seems frontend do not write callfds. Is it
> disabled in qemu now?
>
> And how should I do to implement such fenture?
>
>
> -----Original Messages-----
> *From:*"Li Feng" <fengli at smartx.com>
> *Sent Time:*2018-07-15 16:49:08 (Sunday)
>
> *To:* "杨晔" <yangye at ict.ac.cn>
> *Cc:* "users at dpdk.org" <users at dpdk.org>
> *Subject:* Re: [dpdk-users] Why kickfd from qemu is zero in qemu-dpdk
> vhost-user architecture?
>
> I think you should add some logs at vhost initialization. And what's the
> error code when you call event fd?
>
> 2018年7月15日星期日，杨晔 <yangye at ict.ac.cn> 写道：
>
>>
>> Sure.
>>
>> Here is my code. In virtio_net.c of dpdk.
>> uint16_t
>> rte_vhost_dequeue_burst(int vid, uint16_t queue_id,
>>         struct rte_mempool *mbuf_pool, struct rte_mbuf **pkt
>> s, uint16_t count)
>> {
>>       ...
>>         struct virtio_net *dev;
>>         struct rte_mbuf *rarp_mbuf = NULL;
>>         struct vhost_virtqueue *vq;
>>         uint32_t desc_indexes[MAX_PKT_BURST];
>>         uint32_t used_idx;
>>         uint32_t i = 0;
>>         uint16_t free_entries;
>>         uint16_t avail_idx;
>>
>>         dev = get_device(vid);
>>         if (!dev)
>>                 return 0;
>>
>>         if (unlikely(!is_valid_virt_queue_idx(queue_id, 1,
>> dev->nr_vring))) {
>>                 RTE_LOG(ERR, VHOST_DATA, "(%d) %s: invalid v
>> irtqueue idx %d.\n",
>>                         dev->vid, __func__, queue_id);
>>                 return 0;
>>         }
>>
>>         vq = dev->virtqueue[queue_id];
>>
>>         uint64_t val = 0;
>>         int res = eventfd_read(vq->kickfd,&val);
>>         if(res != 0)
>>         {
>>             RTE_LOG(INFO, VHOST_DATA, "res:(%d)\n", res);
>>             return 0;
>>         }
>>         if(val > 0)
>>             RTE_LOG(INFO, VHOST_DATA, "(%llu)\n", val);
>>         else
>>             return 0;
>>
>> }
>>
>> I just want to use the kickfd from qemu and guest kernel, and change
>> backend DPDK'mode from polling to interrupt.
>>
>> -----Original Messages-----
>> *From:*"Li Feng" <fengli at smartx.com>
>> *Sent Time:*2018-07-15 15:57:16 (Sunday)
>> *To:* "杨晔" <yangye at ict.ac.cn>
>> *Cc:* "users at dpdk.org" <users at dpdk.org>
>> *Subject:* Re: [dpdk-users] Why kickfd from qemu is zero in qemu-dpdk
>> vhost-user architecture?
>>
>> You could paste some code here.
>>
>> Is the eventfd is valid when passing to vhost?
>>
>> Maybe the eventfd is bad.
>>
>>
>> Thanks,
>>
>> Feng Li
>>
>>
>>
>> 手机：13401157876
>>
>> Web：http://www.smartx.com/
>>
>> 地址：北京市海淀区科学院南路2号
>> <https://maps.google.com/?q=%E5%8C%97%E4%BA%AC%E5%B8%82%E6%B5%B7%E6%B7%80%E5%8C%BA%E7%A7%91%E5%AD%A6%E9%99%A2%E5%8D%97%E8%B7%AF2%E5%8F%B7&entry=gmail&source=g>
>> 融科资讯中心C座北楼712
>>
>> 2018-07-15 15:27 GMT+08:00 杨晔 <yangye at ict.ac.cn>:
>>
>>> Hello,
>>>
>>> I use the "vhost-user" mode in the qemu, and the backend is the
>>> dpdk-vhost.
>>>
>>> But when I use the eventfd_read(vq->kickfd,&val) function. It always
>>> return an error, and the val has always been 0.
>>>
>>> The kickfd is the eventfd that passing from qemu to vhost when the vring
>>> is set up and calling the vhost_user_set_vring_kick function.
>>>
>>> It should be a none-zero value when there are packets in the sending
>>> queue.
>>>
>>> The virtio-frontend should notify the backend then do the dequeue
>>> operation.
>>>
>>> Does anyone know about this? I am looking forward to your reply.
>>>
>>>
>>> Thank you.
>>>
>>>
>>>
>>>
>>> --
>>>
>>>
>>> Yang Ye
>>>
>>> Network Research Center, Institute of Computing Technology, Chinese
>>> Academy of Sciences,
>>>
>>> NO.6 Kexueyuan South Road, Zhongguancun, Haidian District, Beijing,
>>> China (100190
>>> <https://maps.google.com/?q=6+Kexueyuan+South+Road,+Zhongguancun,+Haidian+District,+Beijing,+China+(100190&entry=gmail&source=g>
>>> )
>>
>>
>>
>> The SmartX email address is only for business purpose. Any sent message
>> that is not related to the business is not authorized or permitted by
>> SmartX.
>> 本邮箱为北京志凌海纳科技有限公司（SmartX）工作邮箱. 如本邮箱发出的邮件与工作无关,该邮件未得到本公司任何的明示或默示的授权.
>>
>>
>> --
>>
>> Yang Ye
>>
>> Network Research Center, Institute of Computing Technology, Chinese
>> Academy of Sciences,
>>
>> NO.6 Kexueyuan South Road, Zhongguancun, Haidian District, Beijing,
>> China (100190
>> <https://maps.google.com/?q=6+Kexueyuan+South+Road,+Zhongguancun,+Haidian+District,+Beijing,+China+(100190&entry=gmail&source=g>)
>>
>>
>
>
> --
>
> Thanks,
>
> Feng Li
>
>
>
> 手机：13401157876
>
> Web：http://www.smartx.com/
>
> 地址：北京市海淀区科学院南路2号
> <https://maps.google.com/?q=%E5%8C%97%E4%BA%AC%E5%B8%82%E6%B5%B7%E6%B7%80%E5%8C%BA%E7%A7%91%E5%AD%A6%E9%99%A2%E5%8D%97%E8%B7%AF2%E5%8F%B7&entry=gmail&source=g>
> 融科资讯中心C座北楼712
>
>
> The SmartX email address is only for business purpose. Any sent message
> that is not related to the business is not authorized or permitted by
> SmartX.
> 本邮箱为北京志凌海纳科技有限公司（SmartX）工作邮箱. 如本邮箱发出的邮件与工作无关,该邮件未得到本公司任何的明示或默示的授权.
>
>
> --
>
> Yang Ye
>
> Network Research Center, Institute of Computing Technology, Chinese
> Academy of Sciences,
>
> NO.6 Kexueyuan South Road, Zhongguancun, Haidian District, Beijing, China
> (100190
> <https://maps.google.com/?q=6+Kexueyuan+South+Road,+Zhongguancun,+Haidian+District,+Beijing,+China+(100190&entry=gmail&source=g>)
>
>

-- 
The SmartX email address is only for business purpose. Any sent message 
that is not related to the business is not authorized or permitted by 
SmartX.
本邮箱为北京志凌海纳科技有限公司（SmartX）工作邮箱. 如本邮箱发出的邮件与工作无关,该邮件未得到本公司任何的明示或默示的授权.
Previous message: [dpdk-users] Why kickfd from qemu is zero in qemu-dpdk vhost-user architecture?
Next message: [dpdk-users] Problem profiling DPDK
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]
More information about the users mailing list