[PATCH] perf test arm64: Test unwinding using fame-pointer (fp) mode

[PATCH] perf test arm64: Test unwinding using fame-pointer (fp) mode

[German Gomez]

Add a shell script to check that the call-graphs generated using frame
pointers (--call-graph fp) are complete and not missing leaf functions:

  | $ perf test 88 -v
  |  88: Check Arm64 callgraphs are complete in fp mode                  :
  | --- start ---
  | test child forked, pid 8734
  |  + Compiling test program (/tmp/test_program.Cz3yL)...
  |  + Recording (PID=8749)...
  |  + Stopping perf-record...
  | test_program.Cz
  | 		     728 leaf
  | 		     753 parent
  | 		     76c main
  | test child finished with 0
  | ---- end ----
  | Check Arm SPE callgraphs are complete in fp mode: Ok

Fixes: b9f6fbb3b2c2 ("perf arm64: Inject missing frames when using 'perf record --call-graph=fp'")
Suggested-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: German Gomez <german.gomez@arm.com>
---
 .../perf/tests/shell/test_arm_callgraph_fp.sh | 65 +++++++++++++++++++
 1 file changed, 65 insertions(+)
 create mode 100755 tools/perf/tests/shell/test_arm_callgraph_fp.sh

diff --git a/tools/perf/tests/shell/test_arm_callgraph_fp.sh b/tools/perf/tests/shell/test_arm_callgraph_fp.sh
new file mode 100755
index 000000000..c4fa9255b
--- /dev/null
+++ b/tools/perf/tests/shell/test_arm_callgraph_fp.sh
@@ -0,0 +1,65 @@
+#!/bin/sh
+# Check Arm64 callgraphs are complete in fp mode
+# SPDX-License-Identifier: GPL-2.0
+
+lscpu | grep -q "aarch64" || exit 2
+
+if ! [ -x "$(command -v cc)" ]; then
+	echo "failed: no compiler, install gcc"
+	exit 2
+fi
+
+PERF_DATA=$(mktemp /tmp/__perf_test.perf.data.XXXXX)
+TEST_PROGRAM_SOURCE=$(mktemp /tmp/test_program.XXXXX.c)
+TEST_PROGRAM=$(mktemp /tmp/test_program.XXXXX)
+
+cleanup_files()
+{
+	rm -f $PERF_DATA
+	rm -f $TEST_PROGRAM_SOURCE
+	rm -f $TEST_PROGRAM
+}
+
+trap cleanup_files exit term int
+
+cat << EOF > $TEST_PROGRAM_SOURCE
+int a = 0;
+void leaf(void) {
+  for (;;)
+    a += a;
+}
+void parent(void) {
+  leaf();
+}
+int main(void) {
+  parent();
+  return 0;
+}
+EOF
+
+echo " + Compiling test program ($TEST_PROGRAM)..."
+CFLAGS="-O0 -fno-inline -fno-omit-frame-pointer"
+cc $CFLAGS $TEST_PROGRAM_SOURCE -o $TEST_PROGRAM || exit 1
+
+# Add a 1 second delay to skip samples that are not in the leaf() function
+perf record -o $PERF_DATA --call-graph fp -e cycles//u -D 1000 -- $TEST_PROGRAM 2> /dev/null &
+PID=$!
+echo " + Recording (PID=$PID)..."
+sleep 2
+echo " + Stopping perf-record..."
+kill $PID
+wait $PID
+
+# example perf-script output:
+#
+# program 
+# 	728 leaf
+# 	753 parent
+# 	76c main
+# ...
+
+perf script -i $PERF_DATA -F comm,ip,sym | head -n4
+perf script -i $PERF_DATA -F comm,ip,sym | head -n4 |
+	awk '{ if ($2 != "") sym[i++] = $2 } END { if (sym[0] != "leaf" ||
+						       sym[1] != "parent" ||
+						       sym[2] != "main") exit 1 }'
-- 
2.25.1

Re: [PATCH] perf test arm64: Test unwinding using fame-pointer (fp) mode

[German Gomez]

On 01/03/2022 13:34, German Gomez wrote:
> Add a shell script to check that the call-graphs generated using frame
> pointers (--call-graph fp) are complete and not missing leaf functions:
>
> [...]
>
> +cat << EOF > $TEST_PROGRAM_SOURCE
> +int a = 0;
> +void leaf(void) {
> +  for (;;)
> +    a += a;
> +}
> +void parent(void) {
> +  leaf();
> +}
> +int main(void) {
> +  parent();
> +  return 0;
> +}
> +EOF
> +
> +echo " + Compiling test program ($TEST_PROGRAM)..."
> +CFLAGS="-O0 -fno-inline -fno-omit-frame-pointer"

This fails when the test program is compiled with gcc-7, due to missing -g flag.

I will re-spin with this fixed.

> +cc $CFLAGS $TEST_PROGRAM_SOURCE -o $TEST_PROGRAM || exit 1
> +
> +# Add a 1 second delay to skip samples that are not in the leaf() function
> +perf record -o $PERF_DATA --call-graph fp -e cycles//u -D 1000 -- $TEST_PROGRAM 2> /dev/null &
> +PID=$!
> +echo " + Recording (PID=$PID)..."
> +sleep 2
> +echo " + Stopping perf-record..."
> +kill $PID
> +wait $PID
> +
> +# example perf-script output:
> +#
> +# program 
> +# 	728 leaf
> +# 	753 parent
> +# 	76c main
> +# ...
> +
> +perf script -i $PERF_DATA -F comm,ip,sym | head -n4
> +perf script -i $PERF_DATA -F comm,ip,sym | head -n4 |
> +	awk '{ if ($2 != "") sym[i++] = $2 } END { if (sym[0] != "leaf" ||
> +						       sym[1] != "parent" ||
> +						       sym[2] != "main") exit 1 }'