perf test script: Add python script testing support

Basic coverage of python script support from `perf script`.

Committer testing:

  $ perf test 'perf script python'
  107: perf script python tests                                        : Ok
  $ perf test -vv 'perf script python'
  107: perf script python tests:
  --- start ---
  test child forked, pid 595537
  Testing event: sched:sched_switch
  perf script python test [Skipped: failed to record sched:sched_switch]
  Testing event: task-clock
  Generating python script...
  generated Python script: /tmp/__perf_test_script.J4rWj.py
  Executing python script...
  perf script python test [Success: task-clock triggered param_dict]
  ---- end(0) ----
  107: perf script python tests                                        : Ok
  $

Signed-off-by: Ian Rogers <irogers@google.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@linaro.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Leo Yan <leo.yan@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sandipan Das <sandipan.das@amd.com>
Cc: Yujie Liu <yujie.liu@intel.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Author: captain5050

tools/perf/tests/shell/script_python.sh

@@ -0,0 +1,113 @@
+#!/bin/bash
+# perf script python tests
+# SPDX-License-Identifier: GPL-2.0
+
+set -e
+
+# set PERF_EXEC_PATH to find scripts in the source directory
+perfdir=$(dirname "$0")/../..
+if [ -e "$perfdir/scripts/python/Perf-Trace-Util" ]; then
+  export PERF_EXEC_PATH=$perfdir
+fi
+
+
+perfdata=$(mktemp /tmp/__perf_test_script_python.perf.data.XXXXX)
+generated_script=$(mktemp /tmp/__perf_test_script.XXXXX.py)
+
+cleanup() {
+  rm -f "${perfdata}"
+  rm -f "${generated_script}"
+  trap - EXIT TERM INT
+}
+
+trap_cleanup() {
+  echo "Unexpected signal in ${FUNCNAME[1]}"
+  cleanup
+  exit 1
+}
+trap trap_cleanup TERM INT
+trap cleanup EXIT
+
+check_python_support() {
+	if perf check feature -q libpython; then
+		return 0
+	fi
+	echo "perf script python test [Skipped: no libpython support]"
+	return 2
+}
+
+test_script() {
+	local event_name=$1
+	local expected_output=$2
+	local record_opts=$3
+
+	echo "Testing event: $event_name"
+
+	# Try to record. If this fails, it might be permissions or lack of
+	# support. Return 2 to indicate "skip this event" rather than "fail
+	# test".
+	if ! perf record -o "${perfdata}" -e "$event_name" $record_opts -- perf test -w thloop > /dev/null 2>&1; then
+		echo "perf script python test [Skipped: failed to record $event_name]"
+		return 2
+	fi
+
+	echo "Generating python script..."
+	if ! perf script -i "${perfdata}" -g "${generated_script}"; then
+		echo "perf script python test [Failed: script generation for $event_name]"
+		return 1
+	fi
+
+	if [ ! -f "${generated_script}" ]; then
+		echo "perf script python test [Failed: script not generated for $event_name]"
+		return 1
+	fi
+
+	# Perf script -g python doesn't generate process_event for generic
+	# events so append it manually to test that the callback works.
+	if ! grep -q "def process_event" "${generated_script}"; then
+		cat <<EOF >> "${generated_script}"
+
+def process_event(param_dict):
+	print("param_dict: %s" % param_dict)
+EOF
+	fi
+
+	echo "Executing python script..."
+	output=$(perf script -i "${perfdata}" -s "${generated_script}" 2>&1)
+
+	if echo "$output" | grep -q "$expected_output"; then
+		echo "perf script python test [Success: $event_name triggered $expected_output]"
+		return 0
+	else
+		echo "perf script python test [Failed: $event_name did not trigger $expected_output]"
+		echo "Output was:"
+		echo "$output" | head -n 20
+		return 1
+	fi
+}
+
+check_python_support || exit 2
+
+# Try tracepoint first
+test_script "sched:sched_switch" "sched__sched_switch" "-c 1" && res=0 || res=$?
+
+if [ $res -eq 0 ]; then
+	exit 0
+elif [ $res -eq 1 ]; then
+	exit 1
+fi
+
+# If tracepoint skipped (res=2), try task-clock
+# For generic events like task-clock, the generated script uses process_event()
+# which prints the param_dict.
+test_script "task-clock" "param_dict" "-c 100" && res=0 || res=$?
+
+if [ $res -eq 0 ]; then
+	exit 0
+elif [ $res -eq 1 ]; then
+	exit 1
+fi
+
+# If both skipped
+echo "perf script python test [Skipped: Could not record tracepoint or task-clock]"
+exit 2