selftests: forwarding: sch_ets: Add test coverage for ETS Qdisc

This tests the newly-added ETS Qdisc. It runs two to three streams of
traffic, each with a different priority. ETS Qdisc is supposed to allocate
bandwidth according to the DRR algorithm and given weights. After running
the traffic for a while, counters are compared for each stream to check
that the expected ratio is in fact observed.

In order for the DRR process to kick in, a traffic bottleneck must exist in
the first place. In slow path, such bottleneck can be implemented by
wrapping the ETS Qdisc inside a TBF or other shaper. This might however
make the configuration unoffloadable. Instead, on HW datapath, the
bottleneck would be set up by lowering port speed and configuring shared
buffer suitably.

Therefore the test is structured as a core component that implements the
testing, with two wrapper scripts that implement the details of slow path
resp. fast path configuration.

Signed-off-by: Petr Machata <petrm@mellanox.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 227 insertions, 0 deletions

diff --git a/tools/testing/selftests/net/forwarding/sch_ets_tests.sh b/tools/testing/selftests/net/forwarding/sch_ets_tests.sh
new file mode 100644
index 000000000000..3c3b204d47e8
--- /dev/null
+++ b/tools/testing/selftests/net/forwarding/sch_ets_tests.sh
@@ -0,0 +1,227 @@
+# SPDX-License-Identifier: GPL-2.0
+
+# Global interface:
+#  $put -- port under test (e.g. $swp2)
+#  get_stats($band) -- A function to collect stats for band
+#  ets_start_traffic($band) -- Start traffic for this band
+#  ets_change_qdisc($op, $dev, $nstrict, $quanta...) -- Add or change qdisc
+
+# WS describes the Qdisc configuration. It has one value per band (so the
+# number of array elements indicates the number of bands). If the value is
+# 0, it is a strict band, otherwise the it's a DRR band and the value is
+# that band's quantum.
+declare -a WS
+
+qdisc_describe()
+{
+	local nbands=${#WS[@]}
+	local nstrict=0
+	local i
+
+	for ((i = 0; i < nbands; i++)); do
+		if ((!${WS[$i]})); then
+			: $((nstrict++))
+		fi
+	done
+
+	echo -n "ets bands $nbands"
+	if ((nstrict)); then
+		echo -n " strict $nstrict"
+	fi
+	if ((nstrict < nbands)); then
+		echo -n " quanta"
+		for ((i = nstrict; i < nbands; i++)); do
+			echo -n " ${WS[$i]}"
+		done
+	fi
+}
+
+__strict_eval()
+{
+	local desc=$1; shift
+	local d=$1; shift
+	local total=$1; shift
+	local above=$1; shift
+
+	RET=0
+
+	if ((! total)); then
+		check_err 1 "No traffic observed"
+		log_test "$desc"
+		return
+	fi
+
+	local ratio=$(echo "scale=2; 100 * $d / $total" | bc -l)
+	if ((above)); then
+		test $(echo "$ratio > 95.0" | bc -l) -eq 1
+		check_err $? "Not enough traffic"
+		log_test "$desc"
+		log_info "Expected ratio >95% Measured ratio $ratio"
+	else
+		test $(echo "$ratio < 5" | bc -l) -eq 1
+		check_err $? "Too much traffic"
+		log_test "$desc"
+		log_info "Expected ratio <5% Measured ratio $ratio"
+	fi
+}
+
+strict_eval()
+{
+	__strict_eval "$@" 1
+}
+
+notraf_eval()
+{
+	__strict_eval "$@" 0
+}
+
+__ets_dwrr_test()
+{
+	local -a streams=("$@")
+
+	local low_stream=${streams[0]}
+	local seen_strict=0
+	local -a t0 t1 d
+	local stream
+	local total
+	local i
+
+	echo "Testing $(qdisc_describe), streams ${streams[@]}"
+
+	for stream in ${streams[@]}; do
+		ets_start_traffic $stream
+	done
+
+	sleep 10
+
+	t0=($(for stream in ${streams[@]}; do
+		  get_stats $stream
+	      done))
+
+	sleep 10
+
+	t1=($(for stream in ${streams[@]}; do
+		  get_stats $stream
+	      done))
+	d=($(for ((i = 0; i < ${#streams[@]}; i++)); do
+		 echo $((${t1[$i]} - ${t0[$i]}))
+	     done))
+	total=$(echo ${d[@]} | sed 's/ /+/g' | bc)
+
+	for ((i = 0; i < ${#streams[@]}; i++)); do
+		local stream=${streams[$i]}
+		if ((seen_strict)); then
+			notraf_eval "band $stream" ${d[$i]} $total
+		elif ((${WS[$stream]} == 0)); then
+			strict_eval "band $stream" ${d[$i]} $total
+			seen_strict=1
+		elif ((stream == low_stream)); then
+			# Low stream is used as DWRR evaluation reference.
+			continue
+		else
+			multipath_eval "bands $low_stream:$stream" \
+				       ${WS[$low_stream]} ${WS[$stream]} \
+				       ${d[0]} ${d[$i]}
+		fi
+	done
+
+	for stream in ${streams[@]}; do
+		stop_traffic
+	done
+}
+
+ets_dwrr_test_012()
+{
+	__ets_dwrr_test 0 1 2
+}
+
+ets_dwrr_test_01()
+{
+	__ets_dwrr_test 0 1
+}
+
+ets_dwrr_test_12()
+{
+	__ets_dwrr_test 1 2
+}
+
+ets_qdisc_setup()
+{
+	local dev=$1; shift
+	local nstrict=$1; shift
+	local -a quanta=("$@")
+
+	local ndwrr=${#quanta[@]}
+	local nbands=$((nstrict + ndwrr))
+	local nstreams=$(if ((nbands > 3)); then echo 3; else echo $nbands; fi)
+	local priomap=$(seq 0 $((nstreams - 1)))
+	local i
+
+	WS=($(
+		for ((i = 0; i < nstrict; i++)); do
+			echo 0
+		done
+		for ((i = 0; i < ndwrr; i++)); do
+			echo ${quanta[$i]}
+		done
+	))
+
+	ets_change_qdisc $dev $nstrict "$priomap" ${quanta[@]}
+}
+
+ets_set_dwrr_uniform()
+{
+	ets_qdisc_setup $put 0 3300 3300 3300
+}
+
+ets_set_dwrr_varying()
+{
+	ets_qdisc_setup $put 0 5000 3500 1500
+}
+
+ets_set_strict()
+{
+	ets_qdisc_setup $put 3
+}
+
+ets_set_mixed()
+{
+	ets_qdisc_setup $put 1 5000 2500 1500
+}
+
+ets_change_quantum()
+{
+	tc class change dev $put classid 10:2 ets quantum 8000
+	WS[1]=8000
+}
+
+ets_set_dwrr_two_bands()
+{
+	ets_qdisc_setup $put 0 5000 2500
+}
+
+ets_test_strict()
+{
+	ets_set_strict
+	ets_dwrr_test_01
+	ets_dwrr_test_12
+}
+
+ets_test_mixed()
+{
+	ets_set_mixed
+	ets_dwrr_test_01
+	ets_dwrr_test_12
+}
+
+ets_test_dwrr()
+{
+	ets_set_dwrr_uniform
+	ets_dwrr_test_012
+	ets_set_dwrr_varying
+	ets_dwrr_test_012
+	ets_change_quantum
+	ets_dwrr_test_012
+	ets_set_dwrr_two_bands
+	ets_dwrr_test_01
+}