perf test: Add kernel lock contention test

Add a new shell test to check if both normal 'perf lock record' +
contention and BPF (with -b) option are working.

Use 'perf bench sched messaging' as a workload since it creates some
contention for sending and receiving messages.

Signed-off-by: Namhyung Kim <[e-mail]>
Acked-by: Adrian Hunter <[e-mail]>
Acked-by: Ian Rogers <[e-mail]>
Cc: Ingo Molnar <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/tests/shell/lock_contention.sh

···
+#!/bin/sh
+# kernel lock contention analysis test
+# SPDX-License-Identifier: GPL-2.0
+
+set -e
+
+err=0
+perfdata=$(mktemp /tmp/__perf_test.perf.data.XXXXX)
+result=$(mktemp /tmp/__perf_test.result.XXXXX)
+
+cleanup() {
+	rm -f ${perfdata}
+	rm -f ${result}
+	trap - exit term int
+}
+
+trap_cleanup() {
+	cleanup
+	exit ${err}
+}
+trap trap_cleanup exit term int
+
+check() {
+	if [ `id -u` != 0 ]; then
+		echo "[Skip] No root permission"
+		err=2
+		exit
+	fi
+
+	if ! perf list | grep -q lock:contention_begin; then
+		echo "[Skip] No lock contention tracepoints"
+		err=2
+		exit
+	fi
+}
+
+test_record()
+{
+	echo "Testing perf lock record and perf lock contention"
+	perf lock record -o ${perfdata} -- perf bench sched messaging > /dev/null 2>&1
+	# the output goes to the stderr and we expect only 1 output (-E 1)
+	perf lock contention -i ${perfdata} -E 1 -q 2> ${result}
+	if [ $(cat "${result}" | wc -l) != "1" ]; then
+		echo "[Fail] Recorded result count is not 1:" $(cat "${result}" | wc -l)
+		err=1
+		exit
+	fi
+}
+
+test_bpf()
+{
+	echo "Testing perf lock contention --use-bpf"
+
+	if ! perf lock con -b true > /dev/null 2>&1 ; then
+		echo "[Skip] No BPF support"
+		exit
+	fi
+
+	# the perf lock contention output goes to the stderr
+	perf lock con -a -b -E 1 -q -- perf bench sched messaging > /dev/null 2> ${result}
+	if [ $(cat "${result}" | wc -l) != "1" ]; then
+		echo "[Fail] BPF result count is not 1:" $(cat "${result}" | wc -l)
+		err=1
+		exit
+	fi
+}
+
+check
+
+test_record
+test_bpf
+
+exit ${err}