kselftests/ftrace: Add a test case for event pid filtering

Check event is filtered by set_event_pid and options/event-fork.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>

tools/testing/selftests/ftrace/test.d/event/event-pid.tc

+#!/bin/sh
+# description: event tracing - restricts events based on pid
+
+do_reset() {
+    echo > set_event
+    echo > set_event_pid
+    echo 0 > options/event-fork
+    clear_trace
+}
+
+fail() { #msg
+    do_reset
+    echo $1
+    exit $FAIL
+}
+
+yield() {
+    ping localhost -c 1 || sleep .001 || usleep 1 || sleep 1
+}
+
+if [ ! -f set_event -o ! -d events/sched ]; then
+    echo "event tracing is not supported"
+    exit_unsupported
+fi
+
+if [ ! -f set_event_pid ]; then
+    echo "event pid filtering is not supported"
+    exit_unsupported
+fi
+
+reset_tracer
+do_reset
+
+echo 1 > events/sched/sched_switch/enable
+
+yield
+
+count=`cat trace | grep sched_switch | wc -l`
+if [ $count -eq 0 ]; then
+    fail "sched_switch events are not recorded"
+fi
+
+do_reset
+
+read mypid rest < /proc/self/stat
+
+echo $mypid > set_event_pid
+echo 'sched:sched_switch' > set_event
+
+yield
+
+count=`cat trace | grep sched_switch | grep -v "pid=$mypid" | wc -l`
+if [ $count -ne 0 ]; then
+    fail "sched_switch events from other task are recorded"
+fi
+
+do_reset
+
+echo $mypid > set_event_pid
+echo 1 > options/event-fork
+echo 1 > events/sched/sched_switch/enable
+
+yield
+
+count=`cat trace | grep sched_switch | grep -v "pid=$mypid" | wc -l`
+if [ $count -eq 0 ]; then
+    fail "sched_switch events from other task are not recorded"
+fi
+
+do_reset
+
+exit 0