From 5f2c8f4e1070e474642b9dea104f531b8be52e1e Mon Sep 17 00:00:00 2001 From: Thomas Richter Date: Tue, 19 Nov 2024 07:48:56 +0100 Subject: [PATCH] perf/test: fix perf ftrace test on s390 On s390 the perf test case ftrace sometimes fails as follows: # ./perf test ftrace 79: perf ftrace tests : FAILED! # The failure depends on the kernel .config file. Some configurations always work fine, some do not. The ftrace profile test mostly fails, because the ring buffer was not large enough, and some lines (especially the interesting ones with nanosleep in it) where dropped. To achieve success for all tested kernel configurations, enlarge the buffer to store the traces completely without wrapping. The default buffer size is too small for all kernel configurations. Set the buffer size of for the ftrace profile test to 16 MB. Output after: # ./perf test ftrace 79: perf ftrace tests : Ok # Signed-off-by: Thomas Richter Acked-by: Namhyung Kim Cc: agordeev@linux.ibm.com Cc: gor@linux.ibm.com Cc: hca@linux.ibm.com Cc: sumanthk@linux.ibm.com Link: https://lore.kernel.org/r/20241119064856.641446-1-tmricht@linux.ibm.com Suggested-by: Sven Schnelle Suggested-by: Namhyung Kim Signed-off-by: Namhyung Kim --- tools/perf/tests/shell/ftrace.sh | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/perf/tests/shell/ftrace.sh b/tools/perf/tests/shell/ftrace.sh index 11010711efa1..2df05052c324 100755 --- a/tools/perf/tests/shell/ftrace.sh +++ b/tools/perf/tests/shell/ftrace.sh @@ -67,7 +67,7 @@ test_ftrace_latency() { test_ftrace_profile() { echo "perf ftrace profile test" - perf ftrace profile sleep 0.1 > "${output}" + perf ftrace profile -m 16M sleep 0.1 > "${output}" grep ^# "${output}" grep sleep "${output}" grep schedule "${output}"