[ovs-dev] [PATCH ovn] Fix the test case "80. ovn -- 4 HV, 1 LS, 1 LR, packet test with HA distributed router gateway port"

[Mark Michelson]

Acked-by: Mark Michelson <mmichels at redhat.com>

This is a reluctant ack. I think all this does is narrow the possible 
window during which the additional ARP can be received. In theory, it 
may still be possible on a busy/slow enough system to still see this 
problem intermittently. However, it's also possible that the window is 
so small that it would require extraordinary (read: impossible) 
circumstances to occur. Thus why I'm fine with acking this.

I think a better long-term solution in a case like this one is to 
introduce some sort of looser OVN_CHECK_PACKETS macro that expects 
certain packets to be present but will not fail if there are additional 
packets (it may even have a variation to pass only if the extra packets 
are identical to any expected packets). This way, timing inconsistencies 
are eliminated completely.

On 6/17/20 4:38 AM, numans at ovn.org wrote:
> From: Numan Siddique <numans at ovn.org>
> 
> This test case is failing intermittently in my local setup.
> 
> ***********************
> rcv_n=3 exp_n=2
> ovn.at:12: wait succeeded immediately
> ../../tests/ovn.at:9473: sort $rcv_text
> --- expout	2020-06-17 10:57:23.467337249 +0530
> +++ tests/testsuite.dir/at-groups/80/stdout	2020-06-17 10:57:23.469337182 +0530
> @@ -1,2 +1,3 @@
>   f0000001020400000201020308004500001c000000003f110100c0a80102ac1001030035111100080000
>   ffffffffffff00000201020308060001080006040001000002010203ac100101000000000000ac100101
> +ffffffffffff00000201020308060001080006040001000002010203ac100101000000000000ac100101
> *******************
> 
> Before calling 'OVN_CHECK_PACKETS', there is a sleep of 1 second. This is not required,
> and looks like this sleep is causing an extra ARP packet to be received.
> 
> This patch deletes this sleep. The macro OVN_CHECK_PACKETS will anyway wait for the expected
> packets to be received.
> 
> Signed-off-by: Numan Siddique <numans at ovn.org>
> ---
>   tests/ovn.at | 2 --
>   1 file changed, 2 deletions(-)
> 
> diff --git a/tests/ovn.at b/tests/ovn.at
> index 7e1ace556..1987b8062 100644
> --- a/tests/ovn.at
> +++ b/tests/ovn.at
> @@ -9468,8 +9468,6 @@ grep actions=mod_dl_dst:f0:00:00:01:02:04 | wc -l` -eq 1
>       # Resend packet from foo1 to outside1
>       as hv1 ovs-appctl netdev-dummy/receive hv1-vif1 $packet
>   
> -    sleep 1
> -
>       OVN_CHECK_PACKETS([ext1/vif1-tx.pcap], [ext1-vif1.expected])
>       $PYTHON "$ovs_srcdir/utilities/ovs-pcap.in" $active_gw/br-phys_n1-tx.pcap  > packets
>       cat packets | grep $expected > exp
>