[dpdk-dev] [disscussion] A problem about dpdk backup-mode bond switching with mlx4 VF devices

[dpdk-dev] [disscussion] A problem about dpdk backup-mode bond switching with mlx4 VF devices

[chenchanghu]

Hi,
         When I used the mlx4 pmd, I meet a problem about mlx4 VF bond switching which bond mod is backup-mode . The detail test is descripted below.
1.Test environmemt infomation:
  a. Linux distribution: CentOS
  b. dpdk version: dpdk-16.04
  c. Ethernet device : mlx4 VF
  d. pmd info: mlx4 poll-mode-driver

2.Test step:
  a. we bond the mlx4 VF Ethernet device eth7,eth8 into backup-mode by dpdk application. Eth7 and eth8 are both active, and  eth7 is the primary device.
  b. As we know,  the device eth7 , eth8 are also  visible by kernel driver mlx4_en.
  c. Then we config the Ethernet device eth7 down by the command ' ifconfig eth7 down', the expect result is the bond primary device will  not switch.
  d. However we find the dpdk bond primary device switch to eth8 by dpdk maintenance interface one time in all 20 test times.

3.Question:
   Is the VF up or down State of kernel interface has some relations to user-space state? For example, when ifconfig eth7 down, and the user-space will change to down state too.

   Please send your reply to chenchanghu@huawei.com<mailto:chenchanghu@huawei.com>, any suggestion is to be greatefully appreciated.

Re: [dpdk-dev] [disscussion] A problem about dpdk backup-mode bond switching with mlx4 VF devices

[Adrien Mazarguil]

On Tue, Apr 17, 2018 at 06:40:20AM +0000, chenchanghu wrote:
> 
> Hi,
>          When I used the mlx4 pmd, I meet a problem about mlx4 VF bond switching which bond mod is backup-mode . The detail test is descripted below.
> 1.Test environmemt infomation:
>   a. Linux distribution: CentOS
>   b. dpdk version: dpdk-16.04
>   c. Ethernet device : mlx4 VF
>   d. pmd info: mlx4 poll-mode-driver
> 
> 2.Test step:
>   a. we bond the mlx4 VF Ethernet device eth7,eth8 into backup-mode by dpdk application. Eth7 and eth8 are both active, and  eth7 is the primary device.
>   b. As we know,  the device eth7 , eth8 are also  visible by kernel driver mlx4_en.
>   c. Then we config the Ethernet device eth7 down by the command ' ifconfig eth7 down', the expect result is the bond primary device will  not switch.
>   d. However we find the dpdk bond primary device switch to eth8 by dpdk maintenance interface one time in all 20 test times.
> 
> 3.Question:
>    Is the VF up or down State of kernel interface has some relations to user-space state? For example, when ifconfig eth7 down, and the user-space will change to down state too.

Yes, this is expected. Netdevices and the mlx4 DPDK PMD share a common link
status. Bringing a netdevice down causes link status to be down for all its
users. This behavior is documented [1].

[1] http://dpdk.org/doc/guides/nics/mlx4.html#run-time-configuration

-- 
Adrien Mazarguil
6WIND