Commit 51bef03e authored by Kevin Krakauer's avatar Kevin Krakauer Committed by Jakub Kicinski
Browse files

selftests/net: deflake GRO tests 



GRO tests are timing dependent and can easily flake. This is partially
mitigated in gro.sh by giving each subtest 3 chances to pass. However,
this still flakes on some machines. Reduce the flakiness by:

- Bumping retries to 6.
- Setting napi_defer_hard_irqs to 1 to reduce the chance that GRO is
  flushed prematurely. This also lets us reduce the gro_flush_timeout
  from 1ms to 100us.

Tested: Ran `gro.sh -t large` 1000 times. There were no failures with
this change. Ran inside strace to increase flakiness.

Signed-off-by: default avatarKevin Krakauer <krakauer@google.com>
Reviewed-by: default avatarWillem de Bruijn <willemb@google.com>
Link: https://patch.msgid.link/20250226192725.621969-4-krakauer@google.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 41cda572

tools/testing/selftests/net/gro.sh

+2 −2
Original line number Diff line number Diff line
@@ -18,10 +18,10 @@ run_test() { 
  "--smac" "${CLIENT_MAC}" "--test" "${test}" "--verbose" )



  setup_ns

  # Each test is run 3 times to deflake, because given the receive timing,

  # Each test is run 6 times to deflake, because given the receive timing,

  # not all packets that should coalesce will be considered in the same flow

  # on every try.

  for tries in {1..3}; do

  for tries in {1..6}; do

    # Actual test starts here

    ip netns exec $server_ns ./gro "${ARGS[@]}" "--rx" "--iface" "server" \

      1>>log.txt &

tools/testing/selftests/net/setup_veth.sh

+2 −1
Original line number Diff line number Diff line
@@ -11,7 +11,8 @@ setup_veth_ns() { 
	local -r ns_mac="$4"



	[[ -e /var/run/netns/"${ns_name}" ]] || ip netns add "${ns_name}"

	echo 1000000 > "/sys/class/net/${ns_dev}/gro_flush_timeout"

	echo 100000 > "/sys/class/net/${ns_dev}/gro_flush_timeout"

	echo 1 > "/sys/class/net/${ns_dev}/napi_defer_hard_irqs"

	ip link set dev "${ns_dev}" netns "${ns_name}" mtu 65535

	ip -netns "${ns_name}" link set dev "${ns_dev}" up