[ovs-dev] tests: Fix time dependency in overlapping flows modification test.

On slow systems or at high testsuite concurrency sending 256 packets
can take more than 10 seconds.  This is causing expiration of one of
the flows and a subsequent test failure.

Use time warping instead to avoid the time dependency.

Fixes: 21410ff800cc ("dpif-netdev: Fix dpif_netdev_flow_put.")
Reported-at: https://mail.openvswitch.org/pipermail/ovs-discuss/2023-August/052623.html
Reported-by: Sangeetha Elumalai <sangeethaeng2017@gmail.com>
Signed-off-by: Ilya Maximets <i.maximets@ovn.org>
---
 tests/pmd.at | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

man. 28. aug. 2023, 14:16 skrev Ilya Maximets <i.maximets@ovn.org>:

> On slow systems or at high testsuite concurrency sending 256 packets
> can take more than 10 seconds.  This is causing expiration of one of
> the flows and a subsequent test failure.
>
> Use time warping instead to avoid the time dependency.
>
> Fixes: 21410ff800cc ("dpif-netdev: Fix dpif_netdev_flow_put.")
> Reported-at:
> https://mail.openvswitch.org/pipermail/ovs-discuss/2023-August/052623.html
> Reported-by: Sangeetha Elumalai <sangeethaeng2017@gmail.com>
> Signed-off-by: Ilya Maximets <i.maximets@ovn.org>
> ---
>  tests/pmd.at | 8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
>

Debian also saw this failure in their riscv64 build [0] and the build
passes with this patch [1].

Reviewed-By: Frode Nordahl <frode.nordahl@canonical.com>

0:
https://buildd.debian.org/status/fetch.php?pkg=openvswitch&arch=riscv64&ver=3.2.0-1&stamp=1693068090&raw=0
1:
https://buildd.debian.org/status/fetch.php?pkg=openvswitch&arch=riscv64&ver=3.2.0-2&stamp=1693251046&raw=0

--
Frode Nordahl

diff --git a/tests/pmd.at b/tests/pmd.at
> index 7c333a901..7bdaca9e7 100644
> --- a/tests/pmd.at
> +++ b/tests/pmd.at
> @@ -1355,18 +1355,22 @@ AT_CHECK([echo 'table=0,in_port=p1,ip,nw_dst=
> 10.1.0.0/16 actions=ct(commit)' | d
>            ovs-ofctl --bundle replace-flows br0 -])
>  AT_CHECK([ovs-appctl revalidator/wait])
>
> +dnl Prevent flows from expiring.
> +AT_CHECK([ovs-appctl time/stop])
> +
>  AT_CHECK([ovs-appctl netdev-dummy/receive p1
> 'ipv4(src=10.0.0.1,dst=10.1.0.2,proto=6),tcp(src=1,dst=2)'])
>  OVS_WAIT_UNTIL_EQUAL([ovs-appctl dpctl/dump-flows | sed 's/.*core:
> [[0-9]]*//' | strip_xout_keep_actions], [
>  recirc_id(0),in_port(1),packet_type(ns=0,id=0),eth_type(0x0800),ipv4(dst=
> 10.1.0.2/255.255.0.0,frag=no), packets:0, bytes:0, used:never,
> actions:ct(commit)
>  recirc_id(0),in_port(1),packet_type(ns=0,id=0),eth_type(0x0800),ipv4(dst=
> 10.1.2.2/255.255.255.0,frag=no), packets:0, bytes:0, used:0.0s,
> actions:ct(commit)])
>
> -dnl Hold the prefix 10.1.2.2/24 by another 10s.
> -AT_CHECK([ovs-appctl netdev-dummy/receive p1
> 'ipv4(src=10.0.0.1,dst=10.1.2.2,proto=6),tcp(src=1,dst=2)'])
>  dnl Send more 10.1.0.2 to make 10.1.0.0/16 tuple prepend 10.1.2.0/24
> tuple in the pvector of subtables.
>  for i in $(seq 0 256); do
>    AT_CHECK([ovs-appctl netdev-dummy/receive p1
> 'ipv4(src=10.0.0.1,dst=10.1.0.2,proto=6),tcp(src=1,dst=2)'])
>  done
>
> +dnl Warp time enough to trigger subtable optimization.
> +AT_CHECK([ovs-appctl time/warp 500 2000], [0], [ignore])
> +
>  AT_CHECK([echo 'table=0,in_port=p1,ip,nw_dst=10.1.0.0/16 actions=p2' |
> dnl
>            ovs-ofctl --bundle replace-flows br0 -])
>
> --
> 2.40.1
>
>

On 8/28/23 21:44, Frode Nordahl wrote:
> 
> 
> man. 28. aug. 2023, 14:16 skrev Ilya Maximets <i.maximets@ovn.org <mailto:i.maximets@ovn.org>>:
> 
>     On slow systems or at high testsuite concurrency sending 256 packets
>     can take more than 10 seconds.  This is causing expiration of one of
>     the flows and a subsequent test failure.
> 
>     Use time warping instead to avoid the time dependency.
> 
>     Fixes: 21410ff800cc ("dpif-netdev: Fix dpif_netdev_flow_put.")
>     Reported-at: https://mail.openvswitch.org/pipermail/ovs-discuss/2023-August/052623.html <https://mail.openvswitch.org/pipermail/ovs-discuss/2023-August/052623.html>
>     Reported-by: Sangeetha Elumalai <sangeethaeng2017@gmail.com <mailto:sangeethaeng2017@gmail.com>>
>     Signed-off-by: Ilya Maximets <i.maximets@ovn.org <mailto:i.maximets@ovn.org>>
>     ---
>      tests/pmd.at <http://pmd.at> | 8 ++++++--
>      1 file changed, 6 insertions(+), 2 deletions(-)
> 
> 
> Debian also saw this failure in their riscv64 build [0] and the build passes with this patch [1].
> 
> Reviewed-By: Frode Nordahl <frode.nordahl@canonical.com <mailto:frode.nordahl@canonical.com>>

Thanks!  Applied and backported down to 2.17.

Best regards, Ilya Maximets.