selftests/ftrace: Add wakeup tracer testcase

Add a testcase for wakeup tracer.
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Shuah Khan (Samsung OSG) <shuah@kernel.org>

tools/testing/selftests/ftrace/config

@@ -4,6 +4,7 @@ CONFIG_FUNCTION_PROFILER=y
 CONFIG_TRACER_SNAPSHOT=y
 CONFIG_STACK_TRACER=y
 CONFIG_HIST_TRIGGERS=y
+CONFIG_SCHED_TRACER=y
 CONFIG_PREEMPT_TRACER=y
 CONFIG_IRQSOFF_TRACER=y
 CONFIG_PREEMPTIRQ_DELAY_TEST=m

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

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