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                    |
# |   |        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

_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()
{
	local lanes_swp4
	local pg1_size

	# 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
	dcb buffer set dev $swp1 prio-buffer all:0 1:1

	# $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.
	dcb buffer set dev $swp3 prio-buffer all:0 1:1
	dcb pfc set dev $swp3 prio-pfc all:off 1:on

	# $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
	dcb buffer set dev $swp4 prio-buffer all:0 1:1
	dcb pfc set dev $swp4 prio-pfc all:off 1:on
	# PG0 will get autoconfigured to Xoff, give PG1 arbitrarily 100K, which
	# is (-2*MTU) about 80K of delay provision.
	pg1_size=$_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
	# -------

	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
	# -----

	dcb buffer set dev $swp4 buffer-size all:0
	dcb pfc set dev $swp4 prio-pfc all:off
	dcb buffer set dev $swp4 prio-buffer all:0
	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
	# -----

	dcb pfc set dev $swp3 prio-pfc all:off
	dcb buffer set dev $swp3 prio-buffer all:0
	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
	# -----

	dcb buffer set dev $swp1 prio-buffer all:0
	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"
}

bail_on_lldpad "configure DCB" "configure Qdiscs"

trap cleanup EXIT
setup_prepare
setup_wait
tests_run

exit $EXIT_STATUS