selftests: mlxsw: Add a PFC test

Add a test for PFC. Runs 10MB of traffic through a bottleneck and checks
that none of it gets lost.
Signed-off-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

tools/testing/selftests/drivers/net/mlxsw/qos_pfc.sh

+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+#
+# This test injects a 10-MB burst of traffic with VLAN tag and 802.1p priority
+# of 1. This stream is consistently prioritized as priority 1, is put to PG
+# buffer 1, and scheduled at TC 1.
+#
+# - the stream first ingresses through $swp1, where it is forwarded to $swp3
+#
+# - then it ingresses through $swp4. Here it is put to a lossless buffer and put
+#   to a small pool ("PFC pool"). The traffic is forwarded to $swp2, which is
+#   shaped, and thus the PFC pool eventually fills, therefore the headroom
+#   fills, and $swp3 is paused.
+#
+# - since $swp3 now can't send traffic, the traffic ingressing $swp1 is kept at
+#   a pool ("overflow pool"). The overflow pool needs to be large enough to
+#   contain the whole burst.
+#
+# - eventually the PFC pool gets some traffic out, headroom therefore gets some
+#   traffic to the pool, and $swp3 is unpaused again. This way the traffic is
+#   gradually forwarded from the overflow pool, through the PFC pool, out of
+#   $swp2, and eventually to $h2.
+#
+# - if PFC works, all lossless flow packets that ingress through $swp1 should
+#   also be seen ingressing $h2. If it doesn't, there will be drops due to
+#   discrepancy between the speeds of $swp1 and $h2.
+#
+# - it should all play out relatively quickly, so that SLL and HLL will not
+#   cause drops.
+#
+# +-----------------------+
+# | H1                    |
+# |   + $h1.111           |
+# |   | 192.0.2.33/28     |
+# |   |                   |
+# |   + $h1               |
+# +---|-------------------+  +--------------------+
+#     |                      |                    |
+# +---|----------------------|--------------------|---------------------------+
+# |   + $swp1          $swp3 +                    + $swp4                     |
+# |   | iPOOL1        iPOOL0 |                    | iPOOL2                    |
+# |   | ePOOL4        ePOOL5 |                    | ePOOL4                    |
+# |   |                1Gbps |                    | 1Gbps                     |
+# |   |        PFC:enabled=1 |                    | PFC:enabled=1             |
+# | +-|----------------------|-+                +-|------------------------+  |
+# | | + $swp1.111  $swp3.111 + |                | + $swp4.111              |  |
+# | |                          |                |                          |  |
+# | | BR1                      |                | BR2                      |  |
+# | |                          |                |                          |  |
+# | |                          |                |         + $swp2.111      |  |
+# | +--------------------------+                +---------|----------------+  |
+# |                                                       |                   |
+# | iPOOL0: 500KB dynamic                                 |                   |
+# | iPOOL1: 10MB static                                   |                   |
+# | iPOOL2: 1MB static                                    + $swp2             |
+# | ePOOL4: 500KB dynamic                                 | iPOOL0            |
+# | ePOOL5: 10MB static                                   | ePOOL6            |
+# | ePOOL6: "infinite" static                             | 200Mbps shaper    |
+# +-------------------------------------------------------|-------------------+
+#                                                         |
+#                                                     +---|-------------------+
+#                                                     |   + $h2            H2 |
+#                                                     |   |                   |
+#                                                     |   + $h2.111           |
+#                                                     |     192.0.2.34/28     |
+#                                                     +-----------------------+
+#
+# iPOOL0+ePOOL4 is a helper pool for control traffic etc.
+# iPOOL1+ePOOL5 are overflow pools.
+# iPOOL2+ePOOL6 are PFC pools.
+
+ALL_TESTS="
+	ping_ipv4
+	test_qos_pfc
+"
+
+lib_dir=$(dirname $0)/../../../net/forwarding
+
+NUM_NETIFS=6
+source $lib_dir/lib.sh
+source $lib_dir/devlink_lib.sh
+source qos_lib.sh
+
+_1KB=1000
+_100KB=$((100 * _1KB))
+_500KB=$((500 * _1KB))
+_1MB=$((1000 * _1KB))
+_10MB=$((10 * _1MB))
+
+h1_create()
+{
+	simple_if_init $h1
+	mtu_set $h1 10000
+
+	vlan_create $h1 111 v$h1 192.0.2.33/28
+}
+
+h1_destroy()
+{
+	vlan_destroy $h1 111
+
+	mtu_restore $h1
+	simple_if_fini $h1
+}
+
+h2_create()
+{
+	simple_if_init $h2
+	mtu_set $h2 10000
+
+	vlan_create $h2 111 v$h2 192.0.2.34/28
+}
+
+h2_destroy()
+{
+	vlan_destroy $h2 111
+
+	mtu_restore $h2
+	simple_if_fini $h2
+}
+
+switch_create()
+{
+	# pools
+	# -----
+
+	devlink_pool_size_thtype_save 0
+	devlink_pool_size_thtype_save 4
+	devlink_pool_size_thtype_save 1
+	devlink_pool_size_thtype_save 5
+	devlink_pool_size_thtype_save 2
+	devlink_pool_size_thtype_save 6
+
+	devlink_port_pool_th_save $swp1 1
+	devlink_port_pool_th_save $swp2 6
+	devlink_port_pool_th_save $swp3 5
+	devlink_port_pool_th_save $swp4 2
+
+	devlink_tc_bind_pool_th_save $swp1 1 ingress
+	devlink_tc_bind_pool_th_save $swp2 1 egress
+	devlink_tc_bind_pool_th_save $swp3 1 egress
+	devlink_tc_bind_pool_th_save $swp4 1 ingress
+
+	# Control traffic pools. Just reduce the size. Keep them dynamic so that
+	# we don't need to change all the uninteresting quotas.
+	devlink_pool_size_thtype_set 0 dynamic $_500KB
+	devlink_pool_size_thtype_set 4 dynamic $_500KB
+
+	# Overflow pools.
+	devlink_pool_size_thtype_set 1 static $_10MB
+	devlink_pool_size_thtype_set 5 static $_10MB
+
+	# PFC pools. As per the writ, the size of egress PFC pool should be
+	# infinice, but actually it just needs to be large enough to not matter
+	# in practice, so reuse the 10MB limit.
+	devlink_pool_size_thtype_set 2 static $_1MB
+	devlink_pool_size_thtype_set 6 static $_10MB
+
+	# $swp1
+	# -----
+
+	ip link set dev $swp1 up
+	mtu_set $swp1 10000
+	vlan_create $swp1 111
+	ip link set dev $swp1.111 type vlan ingress-qos-map 0:0 1:1
+
+	devlink_port_pool_th_set $swp1 1 $_10MB
+	devlink_tc_bind_pool_th_set $swp1 1 ingress 1 $_10MB
+
+	# Configure qdisc so that we can configure PG and therefore pool
+	# assignment.
+	tc qdisc replace dev $swp1 root handle 1: \
+	   ets bands 8 strict 8 priomap 7 6
+	__mlnx_qos -i $swp1 --prio2buffer=0,1,0,0,0,0,0,0 >/dev/null
+
+	# $swp2
+	# -----
+
+	ip link set dev $swp2 up
+	mtu_set $swp2 10000
+	vlan_create $swp2 111
+	ip link set dev $swp2.111 type vlan egress-qos-map 0:0 1:1
+
+	devlink_port_pool_th_set $swp2 6 $_10MB
+	devlink_tc_bind_pool_th_set $swp2 1 egress 6 $_10MB
+
+	# prio 0->TC0 (band 7), 1->TC1 (band 6). TC1 is shaped.
+	tc qdisc replace dev $swp2 root handle 1: \
+	   ets bands 8 strict 8 priomap 7 6
+	tc qdisc replace dev $swp2 parent 1:7 handle 17: \
+	   tbf rate 200Mbit burst 131072 limit 1M
+
+	# $swp3
+	# -----
+
+	ip link set dev $swp3 up
+	mtu_set $swp3 10000
+	vlan_create $swp3 111
+	ip link set dev $swp3.111 type vlan egress-qos-map 0:0 1:1
+
+	devlink_port_pool_th_set $swp3 5 $_10MB
+	devlink_tc_bind_pool_th_set $swp3 1 egress 5 $_10MB
+
+	# prio 0->TC0 (band 7), 1->TC1 (band 6)
+	tc qdisc replace dev $swp3 root handle 1: \
+	   ets bands 8 strict 8 priomap 7 6
+
+	# Need to enable PFC so that PAUSE takes effect. Therefore need to put
+	# the lossless prio into a buffer of its own. Don't bother with buffer
+	# sizes though, there is not going to be any pressure in the "backward"
+	# direction.
+	__mlnx_qos -i $swp3 --prio2buffer=0,1,0,0,0,0,0,0 >/dev/null
+	__mlnx_qos -i $swp3 --pfc=0,1,0,0,0,0,0,0 >/dev/null
+
+	# $swp4
+	# -----
+
+	ip link set dev $swp4 up
+	mtu_set $swp4 10000
+	vlan_create $swp4 111
+	ip link set dev $swp4.111 type vlan ingress-qos-map 0:0 1:1
+
+	devlink_port_pool_th_set $swp4 2 $_1MB
+	devlink_tc_bind_pool_th_set $swp4 1 ingress 2 $_1MB
+
+	# Configure qdisc so that we can hand-tune headroom.
+	tc qdisc replace dev $swp4 root handle 1: \
+	   ets bands 8 strict 8 priomap 7 6
+	__mlnx_qos -i $swp4 --prio2buffer=0,1,0,0,0,0,0,0 >/dev/null
+	__mlnx_qos -i $swp4 --pfc=0,1,0,0,0,0,0,0 >/dev/null
+	# PG0 will get autoconfigured to Xoff, give PG1 arbitrarily 100K, which
+	# is (-2*MTU) about 80K of delay provision.
+	__mlnx_qos -i $swp3 --buffer_size=0,$_100KB,0,0,0,0,0,0 >/dev/null
+
+	# bridges
+	# -------
+
+	ip link add name br1 type bridge vlan_filtering 0
+	ip link set dev $swp1.111 master br1
+	ip link set dev $swp3.111 master br1
+	ip link set dev br1 up
+
+	ip link add name br2 type bridge vlan_filtering 0
+	ip link set dev $swp2.111 master br2
+	ip link set dev $swp4.111 master br2
+	ip link set dev br2 up
+}
+
+switch_destroy()
+{
+	# Do this first so that we can reset the limits to values that are only
+	# valid for the original static / dynamic setting.
+	devlink_pool_size_thtype_restore 6
+	devlink_pool_size_thtype_restore 5
+	devlink_pool_size_thtype_restore 4
+	devlink_pool_size_thtype_restore 2
+	devlink_pool_size_thtype_restore 1
+	devlink_pool_size_thtype_restore 0
+
+	# bridges
+	# -------
+
+	ip link set dev br2 down
+	ip link set dev $swp4.111 nomaster
+	ip link set dev $swp2.111 nomaster
+	ip link del dev br2
+
+	ip link set dev br1 down
+	ip link set dev $swp3.111 nomaster
+	ip link set dev $swp1.111 nomaster
+	ip link del dev br1
+
+	# $swp4
+	# -----
+
+	__mlnx_qos -i $swp4 --buffer_size=0,0,0,0,0,0,0,0 >/dev/null
+	__mlnx_qos -i $swp4 --pfc=0,0,0,0,0,0,0,0 >/dev/null
+	__mlnx_qos -i $swp4 --prio2buffer=0,0,0,0,0,0,0,0 >/dev/null
+	tc qdisc del dev $swp4 root
+
+	devlink_tc_bind_pool_th_restore $swp4 1 ingress
+	devlink_port_pool_th_restore $swp4 2
+
+	vlan_destroy $swp4 111
+	mtu_restore $swp4
+	ip link set dev $swp4 down
+
+	# $swp3
+	# -----
+
+	__mlnx_qos -i $swp3 --pfc=0,0,0,0,0,0,0,0 >/dev/null
+	__mlnx_qos -i $swp3 --prio2buffer=0,0,0,0,0,0,0,0 >/dev/null
+	tc qdisc del dev $swp3 root
+
+	devlink_tc_bind_pool_th_restore $swp3 1 egress
+	devlink_port_pool_th_restore $swp3 5
+
+	vlan_destroy $swp3 111
+	mtu_restore $swp3
+	ip link set dev $swp3 down
+
+	# $swp2
+	# -----
+
+	tc qdisc del dev $swp2 parent 1:7
+	tc qdisc del dev $swp2 root
+
+	devlink_tc_bind_pool_th_restore $swp2 1 egress
+	devlink_port_pool_th_restore $swp2 6
+
+	vlan_destroy $swp2 111
+	mtu_restore $swp2
+	ip link set dev $swp2 down
+
+	# $swp1
+	# -----
+
+	__mlnx_qos -i $swp1 --prio2buffer=0,0,0,0,0,0,0,0 >/dev/null
+	tc qdisc del dev $swp1 root
+
+	devlink_tc_bind_pool_th_restore $swp1 1 ingress
+	devlink_port_pool_th_restore $swp1 1
+
+	vlan_destroy $swp1 111
+	mtu_restore $swp1
+	ip link set dev $swp1 down
+}
+
+setup_prepare()
+{
+	h1=${NETIFS[p1]}
+	swp1=${NETIFS[p2]}
+
+	swp2=${NETIFS[p3]}
+	h2=${NETIFS[p4]}
+
+	swp3=${NETIFS[p5]}
+	swp4=${NETIFS[p6]}
+
+	h2mac=$(mac_get $h2)
+
+	vrf_prepare
+
+	h1_create
+	h2_create
+	switch_create
+}
+
+cleanup()
+{
+	pre_cleanup
+
+	switch_destroy
+	h2_destroy
+	h1_destroy
+
+	vrf_cleanup
+}
+
+ping_ipv4()
+{
+	ping_test $h1 192.0.2.34
+}
+
+test_qos_pfc()
+{
+	RET=0
+
+	# 10M pool, each packet is 8K of payload + headers
+	local pkts=$((_10MB / 8050))
+	local size=$((pkts * 8050))
+	local in0=$(ethtool_stats_get $swp1 rx_octets_prio_1)
+	local out0=$(ethtool_stats_get $swp2 tx_octets_prio_1)
+
+	$MZ $h1 -p 8000 -Q 1:111 -A 192.0.2.33 -B 192.0.2.34 \
+		-a own -b $h2mac -c $pkts -t udp -q
+	sleep 2
+
+	local in1=$(ethtool_stats_get $swp1 rx_octets_prio_1)
+	local out1=$(ethtool_stats_get $swp2 tx_octets_prio_1)
+
+	local din=$((in1 - in0))
+	local dout=$((out1 - out0))
+
+	local pct_in=$((din * 100 / size))
+
+	((pct_in > 95 && pct_in < 105))
+	check_err $? "Relative ingress out of expected bounds, $pct_in% should be 100%"
+
+	((dout == din))
+	check_err $? "$((din - dout)) bytes out of $din ingressed got lost"
+
+	log_test "PFC"
+}
+
+trap cleanup EXIT
+
+bail_on_lldpad
+setup_prepare
+setup_wait
+tests_run
+
+exit $EXIT_STATUS