On Sat, Oct 21, 2023 at 05:04:48PM +0200, Frode Nordahl wrote: > Many system tests currently use ping with the combination of a > low packet count (-c 3), short interval between sends (-i 0.3) > and a _deadline_ of 2 seconds (-d 2). > > This combination of options may lead to a situation where more > than count packets are sent however ping will stop when count > packets are received. This results in a failed test due to how > the result is checked, for example: > > ping6 -q -c 3 -i 0.3 -w 2 fc00::3 | FORMAT_PING > @@ -1,2 +1,2 @@ > -3 packets transmitted, 3 received, 0% packet loss, time 0ms > +4 packets transmitted, 3 received, 25% packet loss, time 0ms > > To reiterate, in the above example there is no packet loss, but > ping stops after _receiving_ 3 packets, not bothering with > waiting for the response to the fourth packet it just sent out. > > If we look at the iputils ping manual for the -w deadline option > we can read that this is expected behavior: > > > Specify a timeout, in seconds, before ping exits regardless of > > how many packets have been sent or received. In this case ping > > does not stop after count packet are sent, it waits either for > > deadline expire or until count probes are answered or for some > > error notification from network. > > To avoid these kinds of failures in checks where a response is > expected, we replace ping -w with ping -W. > > We keep ping -w for checks where it is expected to NOT get a > response. > > Signed-off-by: Frode Nordahl <[email protected]>
Thanks Frode, TIL about -w and -W. Acked-by: Simon Horman <[email protected]> _______________________________________________ dev mailing list [email protected] https://mail.openvswitch.org/mailman/listinfo/ovs-dev
