From 8f7f03e8cd3363e5e12dd42036c21e50207975b2 Mon Sep 17 00:00:00 2001 From: Amit Cohen Date: Wed, 17 Jan 2024 16:04:21 +0100 Subject: [PATCH] selftests: mlxsw: qos_pfc: Adjust the test to support 8 lanes [ Upstream commit b34f4de6d30cbaa8fed905a5080b6eace8c84dc7 ] 'qos_pfc' test checks PFC behavior. The idea is to limit the traffic using a shaper somewhere in the flow of the packets. In this area, the buffer is smaller than the buffer at the beginning of the flow, so it fills up until there is no more space left. The test configures there PFC which is supposed to notice that the headroom is filling up and send PFC Xoff to indicate the transmitter to stop sending traffic for the priorities sharing this PG. The Xon/Xoff threshold is auto-configured and always equal to 2*(MTU rounded up to cell size). Even after sending the PFC Xoff packet, traffic will keep arriving until the transmitter receives and processes the PFC packet. This amount of traffic is known as the PFC delay allowance. Currently the buffer for the delay traffic is configured as 100KB. The MTU in the test is 10KB, therefore the threshold for Xoff is about 20KB. This allows 80KB extra to be stored in this buffer. 8-lane ports use two buffers among which the configured buffer is split, the Xoff threshold then applies to each buffer in parallel. The test does not take into account the behavior of 8-lane ports, when the ports are configured to 400Gbps with 8 lanes or 800Gbps with 8 lanes, packets are dropped and the test fails. Check if the relevant ports use 8 lanes, in such case double the size of the buffer, as the headroom is split half-half. Cc: Shuah Khan Fixes: bfa804784e32 ("selftests: mlxsw: Add a PFC test") Signed-off-by: Amit Cohen Reviewed-by: Ido Schimmel Signed-off-by: Petr Machata Acked-by: Paolo Abeni Link: https://lore.kernel.org/r/23ff11b7dff031eb04a41c0f5254a2b636cd8ebb.1705502064.git.petrm@nvidia.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- .../selftests/drivers/net/mlxsw/qos_pfc.sh | 18 +++++++++++++++++- 1 file changed, 17 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/drivers/net/mlxsw/qos_pfc.sh b/tools/testing/selftests/drivers/net/mlxsw/qos_pfc.sh index f9858e221996..6a3002fbcf43 100755 --- a/tools/testing/selftests/drivers/net/mlxsw/qos_pfc.sh +++ b/tools/testing/selftests/drivers/net/mlxsw/qos_pfc.sh @@ -121,6 +121,9 @@ h2_destroy() switch_create() { + local lanes_swp4 + local pg1_size + # pools # ----- @@ -230,7 +233,20 @@ switch_create() dcb pfc set dev $swp4 prio-pfc all:off 1:on # PG0 will get autoconfigured to Xoff, give PG1 arbitrarily 100K, which # is (-2*MTU) about 80K of delay provision. - dcb buffer set dev $swp4 buffer-size all:0 1:$_100KB + pg1_size=$_100KB + + setup_wait_dev_with_timeout $swp4 + + lanes_swp4=$(ethtool $swp4 | grep 'Lanes:') + lanes_swp4=${lanes_swp4#*"Lanes: "} + + # 8-lane ports use two buffers among which the configured buffer + # is split, so double the size to get twice (20K + 80K). + if [[ $lanes_swp4 -eq 8 ]]; then + pg1_size=$((pg1_size * 2)) + fi + + dcb buffer set dev $swp4 buffer-size all:0 1:$pg1_size # bridges # -------