perf test stat+json_output: Write JSON output to a file

Write the JSON output to a file, then sanity check this output. This
avoids problems with debug/warning/error output corrupting the file
format.
Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sumanth Korikkar <sumanthk@linux.ibm.com>
Cc: Thomas Richter <tmricht@linux.ibm.com>
Link: https://lore.kernel.org/r/20230408054456.3001367-2-irogers@google.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/tests/shell/lib/perf_json_output_lint.py

@@ -17,9 +17,10 @@ ap.add_argument('--per-thread', action='store_true')
 ap.add_argument('--per-die', action='store_true')
 ap.add_argument('--per-node', action='store_true')
 ap.add_argument('--per-socket', action='store_true')
+ap.add_argument('--file', type=argparse.FileType('r'), default=sys.stdin)
 args = ap.parse_args()
 
-Lines = sys.stdin.readlines()
+Lines = args.file.readlines()
 
 def isfloat(num):
   try:

tools/perf/tests/shell/stat+json_output.sh

@@ -23,6 +23,20 @@ then
 	fi
 fi
 
+stat_output=$(mktemp /tmp/__perf_test.stat_output.json.XXXXX)
+
+cleanup() {
+  rm -f "${stat_output}"
+
+  trap - EXIT TERM INT
+}
+
+trap_cleanup() {
+  cleanup
+  exit 1
+}
+trap trap_cleanup EXIT TERM INT
+
 # Return true if perf_event_paranoid is > $1 and not running as root.
 function ParanoidAndNotRoot()
 {
@@ -32,7 +46,8 @@ function ParanoidAndNotRoot()
 check_no_args()
 {
 	echo -n "Checking json output: no args "
-	perf stat -j true 2>&1 | $PYTHON $pythonchecker --no-args
+	perf stat -j -o "${stat_output}" true
+	$PYTHON $pythonchecker --no-args --file "${stat_output}"
 	echo "[Success]"
 }
 
@@ -44,27 +59,29 @@ check_system_wide()
 		echo "[Skip] paranoia and not root"
 		return
 	fi
-	perf stat -j -a true 2>&1 | $PYTHON $pythonchecker --system-wide
+	perf stat -j -a -o "${stat_output}" true
+	$PYTHON $pythonchecker --system-wide --file "${stat_output}"
 	echo "[Success]"
 }
 
 check_system_wide_no_aggr()
 {
-	echo -n "Checking json output: system wide "
+	echo -n "Checking json output: system wide no aggregation "
 	if ParanoidAndNotRoot 0
 	then
 		echo "[Skip] paranoia and not root"
 		return
 	fi
-	echo -n "Checking json output: system wide no aggregation "
-	perf stat -j -A -a --no-merge true 2>&1 | $PYTHON $pythonchecker --system-wide-no-aggr
+	perf stat -j -A -a --no-merge -o "${stat_output}" true
+	$PYTHON $pythonchecker --system-wide-no-aggr --file "${stat_output}"
 	echo "[Success]"
 }
 
 check_interval()
 {
 	echo -n "Checking json output: interval "
-	perf stat -j -I 1000 true 2>&1 | $PYTHON $pythonchecker --interval
+	perf stat -j -I 1000 -o "${stat_output}" true
+	$PYTHON $pythonchecker --interval --file "${stat_output}"
 	echo "[Success]"
 }
 
@@ -72,7 +89,8 @@ check_interval()
 check_event()
 {
 	echo -n "Checking json output: event "
-	perf stat -j -e cpu-clock true 2>&1 | $PYTHON $pythonchecker --event
+	perf stat -j -e cpu-clock -o "${stat_output}" true
+	$PYTHON $pythonchecker --event --file "${stat_output}"
 	echo "[Success]"
 }
 
@@ -84,7 +102,8 @@ check_per_core()
 		echo "[Skip] paranoia and not root"
 		return
 	fi
-	perf stat -j --per-core -a true 2>&1 | $PYTHON $pythonchecker --per-core
+	perf stat -j --per-core -a -o "${stat_output}" true
+	$PYTHON $pythonchecker --per-core --file "${stat_output}"
 	echo "[Success]"
 }
 
@@ -96,7 +115,8 @@ check_per_thread()
 		echo "[Skip] paranoia and not root"
 		return
 	fi
-	perf stat -j --per-thread -a true 2>&1 | $PYTHON $pythonchecker --per-thread
+	perf stat -j --per-thread -a -o "${stat_output}" true
+	$PYTHON $pythonchecker --per-thread --file "${stat_output}"
 	echo "[Success]"
 }
 
@@ -108,7 +128,8 @@ check_per_die()
 		echo "[Skip] paranoia and not root"
 		return
 	fi
-	perf stat -j --per-die -a true 2>&1 | $PYTHON $pythonchecker --per-die
+	perf stat -j --per-die -a -o "${stat_output}" true
+	$PYTHON $pythonchecker --per-die --file "${stat_output}"
 	echo "[Success]"
 }
 
@@ -120,7 +141,8 @@ check_per_node()
 		echo "[Skip] paranoia and not root"
 		return
 	fi
-	perf stat -j --per-node -a true 2>&1 | $PYTHON $pythonchecker --per-node
+	perf stat -j --per-node -a -o "${stat_output}" true
+	$PYTHON $pythonchecker --per-node --file "${stat_output}"
 	echo "[Success]"
 }
 
@@ -132,7 +154,8 @@ check_per_socket()
 		echo "[Skip] paranoia and not root"
 		return
 	fi
-	perf stat -j --per-socket -a true 2>&1 | $PYTHON $pythonchecker --per-socket
+	perf stat -j --per-socket -a -o "${stat_output}" true
+	$PYTHON $pythonchecker --per-socket --file "${stat_output}"
 	echo "[Success]"
 }
 
@@ -179,4 +202,5 @@ then
 else
 	echo "[Skip] Skipping tests for system_wide_no_aggr, per_core, per_die and per_socket since socket id exposed via topology is invalid"
 fi
+cleanup
 exit 0