linux-kernel - [PATCH v1 1/4] perf test shell lbr: Avoid failures with perf event paranoia

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Message-ID: <20250821221834.1312002-2-irogers@google.com>
Date: Thu, 21 Aug 2025 15:18:31 -0700
From: Ian Rogers <irogers@...gle.com>
To: Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...hat.com>, 
	Arnaldo Carvalho de Melo <acme@...nel.org>, Namhyung Kim <namhyung@...nel.org>, 
	Mark Rutland <mark.rutland@....com>, 
	Alexander Shishkin <alexander.shishkin@...ux.intel.com>, Jiri Olsa <jolsa@...nel.org>, 
	Ian Rogers <irogers@...gle.com>, Adrian Hunter <adrian.hunter@...el.com>, 
	Kan Liang <kan.liang@...ux.intel.com>, Chun-Tse Shao <ctshao@...gle.com>, 
	James Clark <james.clark@...aro.org>, Howard Chu <howardchu95@...il.com>, 
	linux-kernel@...r.kernel.org, linux-perf-users@...r.kernel.org
Subject: [PATCH v1 1/4] perf test shell lbr: Avoid failures with perf event paranoia

When not running as root and with higher perf event paranoia values
the perf record LBR tests could fail rather than skipping the
problematic tests. Add the sensitivity to the test and confirm it
passes with paranoia values from -1 to 2.

Fixes: 32559b99e0f5 ("perf test: Add set of perf record LBR tests")
Signed-off-by: Ian Rogers <irogers@...gle.com>
---
 tools/perf/tests/shell/record_lbr.sh | 26 ++++++++++++++++++++------
 1 file changed, 20 insertions(+), 6 deletions(-)

diff --git a/tools/perf/tests/shell/record_lbr.sh b/tools/perf/tests/shell/record_lbr.sh
index 6fcb5e52b9b4..78a02e90ece1 100755
--- a/tools/perf/tests/shell/record_lbr.sh
+++ b/tools/perf/tests/shell/record_lbr.sh
@@ -4,6 +4,10 @@
 
 set -e
 
+ParanoidAndNotRoot() {
+  [ "$(id -u)" != 0 ] && [ "$(cat /proc/sys/kernel/perf_event_paranoid)" -gt $1 ]
+}
+
 if [ ! -f /sys/bus/event_source/devices/cpu/caps/branches ] &&
    [ ! -f /sys/bus/event_source/devices/cpu_core/caps/branches ]
 then
@@ -23,6 +27,7 @@ cleanup() {
 }
 
 trap_cleanup() {
+  echo "Unexpected signal in ${FUNCNAME[1]}"
   cleanup
   exit 1
 }
@@ -123,8 +128,11 @@ lbr_test "-j ind_call" "any indirect call" 2
 lbr_test "-j ind_jmp" "any indirect jump" 100
 lbr_test "-j call" "direct calls" 2
 lbr_test "-j ind_call,u" "any indirect user call" 100
-lbr_test "-a -b" "system wide any branch" 2
-lbr_test "-a -j any_call" "system wide any call" 2
+if ! ParanoidAndNotRoot 1
+then
+  lbr_test "-a -b" "system wide any branch" 2
+  lbr_test "-a -j any_call" "system wide any call" 2
+fi
 
 # Parallel
 parallel_lbr_test "-b" "parallel any branch" 100 &
@@ -141,10 +149,16 @@ parallel_lbr_test "-j call" "parallel direct calls" 100 &
 pid6=$!
 parallel_lbr_test "-j ind_call,u" "parallel any indirect user call" 100 &
 pid7=$!
-parallel_lbr_test "-a -b" "parallel system wide any branch" 100 &
-pid8=$!
-parallel_lbr_test "-a -j any_call" "parallel system wide any call" 100 &
-pid9=$!
+if ParanoidAndNotRoot 1
+then
+  pid8=
+  pid9=
+else
+  parallel_lbr_test "-a -b" "parallel system wide any branch" 100 &
+  pid8=$!
+  parallel_lbr_test "-a -j any_call" "parallel system wide any call" 100 &
+  pid9=$!
+fi
 
 for pid in $pid1 $pid2 $pid3 $pid4 $pid5 $pid6 $pid7 $pid8 $pid9
 do
-- 
2.51.0.rc2.233.g662b1ed5c5-goog