This test works by injecting into a port with a maxed-out queue a couple packets and checks if a corresponding number of packets were dropped. This has worked well on Spectrum<4, but on Spectrum-4 it has been noisy. This is in line with the observation that on Spectrum-4, queue size tends to fluctuate more. A handful of packets could then still be accepted to the queue even though it was nominally full just recently.
In order to accommodate this behavior, send many more packets. The buffer can fit N extra packets, but not N% packets. This therefore allows us to set wider absolute margins, while actually narrowing them relatively.
Signed-off-by: Petr Machata petrm@nvidia.com Reviewed-by: Ido Schimmel idosch@nvidia.com --- .../selftests/drivers/net/mlxsw/sch_red_core.sh | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-)
diff --git a/tools/testing/selftests/drivers/net/mlxsw/sch_red_core.sh b/tools/testing/selftests/drivers/net/mlxsw/sch_red_core.sh index b1ff395b3880..316444389c4e 100644 --- a/tools/testing/selftests/drivers/net/mlxsw/sch_red_core.sh +++ b/tools/testing/selftests/drivers/net/mlxsw/sch_red_core.sh @@ -653,20 +653,22 @@ do_drop_test() build_backlog $vlan $((3 * limit / 2)) udp >/dev/null
base=$($fetch_counter) - send_packets $vlan udp 11 + send_packets $vlan udp 100
- now=$(busywait 1100 until_counter_is ">= $((base + 10))" $fetch_counter) - check_err $? "Dropped packets not observed: 11 expected, $((now - base)) seen" + now=$(busywait 1100 until_counter_is ">= $((base + 95))" $fetch_counter) + check_err $? "${trigger}ped packets not observed: 100 expected, $((now - base)) seen"
# When no extra traffic is injected, there should be no mirroring. - busywait 1100 until_counter_is ">= $((base + 20))" $fetch_counter >/dev/null + busywait 1100 until_counter_is ">= $((base + 110))" \ + $fetch_counter >/dev/null check_fail $? "Spurious packets observed"
# When the rule is uninstalled, there should be no mirroring. qevent_rule_uninstall_$subtest - send_packets $vlan udp 11 - busywait 1100 until_counter_is ">= $((base + 20))" $fetch_counter >/dev/null - check_fail $? "Spurious packets observed after uninstall" + send_packets $vlan udp 100 + now=$(busywait 1100 until_counter_is ">= $((base + 110))" \ + $fetch_counter) + check_fail $? "$((now - base)) spurious packets observed after uninstall"
log_test "TC $((vlan - 10)): ${trigger}ped packets $subtest'd"