selftests/ftrace: Add wakeup_rt tracer testcase

Add a testcase for wakeup_rt tracer. This requires chrt
command to test.
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Shuah Khan (Samsung OSG) <shuah@kernel.org>

tools/testing/selftests/ftrace/test.d/tracer/wakeup_rt.tc

+#!/bin/sh
+# SPDX-License-Identifier: GPL2.0
+# description: Test wakeup RT tracer
+
+if ! which chrt ; then
+  echo "chrt is not found. This test requires chrt command."
+  exit_unresolved
+fi
+
+if ! grep -wq "wakeup_rt" available_tracers ; then
+  echo "wakeup_rt tracer is not supported"
+  exit_unsupported
+fi
+
+echo wakeup_rt > current_tracer
+echo 1 > tracing_on
+echo 0 > tracing_max_latency
+
+: "Wakeup a realtime task"
+chrt -f 5 sleep 1
+
+echo 0 > tracing_on
+grep "+ \[[[:digit:]]*\]" trace
+grep "==> \[[[:digit:]]*\]" trace
+