From 022245067f07ab913d27054ee9e1fab45256acd5 Mon Sep 17 00:00:00 2001
From: Jan Polensky <japo@linux.ibm.com>
Date: Fri, 25 Jul 2025 19:08:01 +0200
Subject: [PATCH] perf test: Ensure lock contention using pipe mode

The 'kernel lock contention analysis test' requires reliable triggering
of lock contention. On some systems, previous benchmark calls failed to
generate sufficient contention due to low system activity or resource
limits.

This patch adds the -p (pipe) option to all calls of perf bench sched
messaging, ensuring consistent lock contention without relying on
socket-based communication.

Suggested-by: Thomas Richter <tmricht@linux.ibm.com>
Signed-off-by: Jan Polensky <japo@linux.ibm.com>
Link: https://lore.kernel.org/r/20250725170801.3176678-1-japo@linux.ibm.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
 tools/perf/tests/shell/lock_contention.sh | 26 +++++++++++------------
 1 file changed, 13 insertions(+), 13 deletions(-)

diff --git a/tools/perf/tests/shell/lock_contention.sh b/tools/perf/tests/shell/lock_contention.sh
index dde5bc737eb26..d33d9e4392b06 100755
--- a/tools/perf/tests/shell/lock_contention.sh
+++ b/tools/perf/tests/shell/lock_contention.sh
@@ -44,7 +44,7 @@ check() {
 test_record()
 {
 	echo "Testing perf lock record and perf lock contention"
-	perf lock record -o ${perfdata} -- perf bench sched messaging > /dev/null 2>&1
+	perf lock record -o ${perfdata} -- perf bench sched messaging -p > /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
@@ -64,7 +64,7 @@ test_bpf()
 	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}
+	perf lock con -a -b -E 1 -q -- perf bench sched messaging -p > /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
@@ -75,7 +75,7 @@ test_bpf()
 test_record_concurrent()
 {
 	echo "Testing perf lock record and perf lock contention at the same time"
-	perf lock record -o- -- perf bench sched messaging 2> /dev/null | \
+	perf lock record -o- -- perf bench sched messaging -p 2> /dev/null | \
 	perf lock contention -i- -E 1 -q 2> ${result}
 	if [ "$(cat "${result}" | wc -l)" != "1" ]; then
 		echo "[Fail] Recorded result count is not 1:" "$(cat "${result}" | wc -l)"
@@ -99,7 +99,7 @@ test_aggr_task()
 	fi
 
 	# the perf lock contention output goes to the stderr
-	perf lock con -a -b -t -E 1 -q -- perf bench sched messaging > /dev/null 2> ${result}
+	perf lock con -a -b -t -E 1 -q -- perf bench sched messaging -p > /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
@@ -122,7 +122,7 @@ test_aggr_addr()
 	fi
 
 	# the perf lock contention output goes to the stderr
-	perf lock con -a -b -l -E 1 -q -- perf bench sched messaging > /dev/null 2> ${result}
+	perf lock con -a -b -l -E 1 -q -- perf bench sched messaging -p > /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
@@ -140,7 +140,7 @@ test_aggr_cgroup()
 	fi
 
 	# the perf lock contention output goes to the stderr
-	perf lock con -a -b -g -E 1 -q -- perf bench sched messaging > /dev/null 2> ${result}
+	perf lock con -a -b -g -E 1 -q -- perf bench sched messaging -p > /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
@@ -162,7 +162,7 @@ test_type_filter()
 		return
 	fi
 
-	perf lock con -a -b -Y spinlock -q -- perf bench sched messaging > /dev/null 2> ${result}
+	perf lock con -a -b -Y spinlock -q -- perf bench sched messaging -p > /dev/null 2> ${result}
 	if [ "$(grep -c -v spinlock "${result}")" != "0" ]; then
 		echo "[Fail] BPF result should not have non-spinlocks:" "$(cat "${result}")"
 		err=1
@@ -194,7 +194,7 @@ test_lock_filter()
 		return
 	fi
 
-	perf lock con -a -b -L tasklist_lock -q -- perf bench sched messaging > /dev/null 2> ${result}
+	perf lock con -a -b -L tasklist_lock -q -- perf bench sched messaging -p > /dev/null 2> ${result}
 	if [ "$(grep -c -v "${test_lock_filter_type}" "${result}")" != "0" ]; then
 		echo "[Fail] BPF result should not have non-${test_lock_filter_type} locks:" "$(cat "${result}")"
 		err=1
@@ -222,7 +222,7 @@ test_stack_filter()
 		return
 	fi
 
-	perf lock con -a -b -S unix_stream -E 1 -q -- perf bench sched messaging > /dev/null 2> ${result}
+	perf lock con -a -b -S unix_stream -E 1 -q -- perf bench sched messaging -p > /dev/null 2> ${result}
 	if [ "$(cat "${result}" | wc -l)" != "1" ]; then
 		echo "[Fail] BPF result should have a lock from unix_stream:" "$(cat "${result}")"
 		err=1
@@ -250,7 +250,7 @@ test_aggr_task_stack_filter()
 		return
 	fi
 
-	perf lock con -a -b -t -S unix_stream -E 1 -q -- perf bench sched messaging > /dev/null 2> ${result}
+	perf lock con -a -b -t -S unix_stream -E 1 -q -- perf bench sched messaging -p > /dev/null 2> ${result}
 	if [ "$(cat "${result}" | wc -l)" != "1" ]; then
 		echo "[Fail] BPF result should have a task from unix_stream:" "$(cat "${result}")"
 		err=1
@@ -266,7 +266,7 @@ test_cgroup_filter()
 		return
 	fi
 
-	perf lock con -a -b -g -E 1 -F wait_total -q -- perf bench sched messaging > /dev/null 2> ${result}
+	perf lock con -a -b -g -E 1 -F wait_total -q -- perf bench sched messaging -p > /dev/null 2> ${result}
 	if [ "$(cat "${result}" | wc -l)" != "1" ]; then
 		echo "[Fail] BPF result should have a cgroup result:" "$(cat "${result}")"
 		err=1
@@ -274,7 +274,7 @@ test_cgroup_filter()
 	fi
 
 	cgroup=$(cat "${result}" | awk '{ print $3 }')
-	perf lock con -a -b -g -E 1 -G "${cgroup}" -q -- perf bench sched messaging > /dev/null 2> ${result}
+	perf lock con -a -b -g -E 1 -G "${cgroup}" -q -- perf bench sched messaging -p > /dev/null 2> ${result}
 	if [ "$(cat "${result}" | wc -l)" != "1" ]; then
 		echo "[Fail] BPF result should have a result with cgroup filter:" "$(cat "${cgroup}")"
 		err=1
@@ -309,7 +309,7 @@ test_csv_output()
 	fi
 
 	# the perf lock contention output goes to the stderr
-	perf lock con -a -b -E 1 -x , --output ${result} -- perf bench sched messaging > /dev/null 2>&1
+	perf lock con -a -b -E 1 -x , --output ${result} -- perf bench sched messaging -p > /dev/null 2>&1
 	output=$(grep -v "^#" ${result} | tr -d -c , | wc -c)
 	if [ "${header}" != "${output}" ]; then
 		echo "[Fail] BPF result does not match the number of commas: ${header} != ${output}"
-- 
2.47.2