[ovs-dev] [PATCH] system-traffic.at: Make nsh test more robust.

William Tu u9012063 at gmail.com
Fri Jul 19 14:20:31 UTC 2019

On Thu, Jul 18, 2019 at 04:26:30PM +0300, Ilya Maximets wrote:
> On 18.07.2019 0:21, William Tu wrote:
> > The patch adds '-n' to tcpdump to avoid address coverting. Since '-U' is
> > used to output to stdout, simply use 'cat' to search result.
> > Use OVS_WAIT_UNTIL instead of sleep ,and also remove/add some newlines.
> Thanks for working on this!
> There are few more issues that makes these tests fail on my rhel8 VM.
> 1. tcpdump buffers the packets. It's better to add '-l' too, so there
>    will be no delays due to buffering.
OK Will add it.

> 2. Tests are strange. For some reason they are capturing packets on the
>    transmission side. This doesn't work for AF_XDP for example, because
>    tcpdump can't catch the packets on xdp xmit. So, my suggestion here is
>    to start tcpdump inside the network namespace for 'p1'/'p2' interfaces
>    instead of 'ovs-p1'/'ovs-p2'. Like this:
Good cache. I did not test using AF_XDP.
Will fix it.

>     NS_CHECK_EXEC([at_ns1], [tcpdump -l -n -xx -U -i p1 > p1.pcap &])
> 3. Just a note: no need to redirect stderr of a simple cat.
> Best regards, Ilya Maximets.

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