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

Ilya Maximets i.maximets at samsung.com
Thu Jul 18 13:26:30 UTC 2019

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.

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:

    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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