[ovs-discuss] ovs route refresh problem

Yinpeijun yinpeijun at huawei.com
Fri Feb 23 03:30:59 UTC 2018

>>On Sun, Feb 11, 2018 at 07:27:34AM +0000, Yinpeijun wrote:
>> Hi all
>>                 Recently , I run a test two VM commulication with 
>> vxlan and ovs+dpdk networking(ovs2.7.2). when I add 200 virtual device 
>> on the physical service  of the commulicate vm then check the ping result,  there  is  loss packet statistics. Then I use vlan and ovs+dpdk networking, do the same thing , there is no loss packets statistics.
>>                 I read the source code and add some log to confirm the 
>> problem,  the final problem I think is unreasonable routing refresh,  
>> in route_table_rest function delete all items before readding, so in the middle of the interval  ovs_router_lookup  can not find the route then cause packet drop.  So I think the implementation need to optimize, Any advice on how to optimize it?

>I don't fully understand your use case.  However, if you're not using DPDK, then OVS isn't doing routing in userspace so this is probably not the problem.

Thank you for your replay, the test case just for reproduce the problem. The actual  scene is to create or migrate virtual machines in openstack env. Correspondence will be created linux bridge
and other virtual device.

There is also have problem in netdev dataptah without dpdk.  vxlan tunnel need route in userspace and ovs maintain the route table as follow:
ovs-appctl ovs/route/show
Route Table:
Cached: x.xx.1.10/32 dev eth0 SRC x.xx.1.10
Cached: dev brcps SRC
Cached: dev lo SRC

So when I create virtual device trigger ovs refresh the route then affect the already existing virtual machine communication.

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