[PATCH 3/3] selftests/ftrace: Add snapshot and tracing_on test case

[Masami Hiramatsu]

Add a testcase for checking snapshot and tracing_on
relationship. This ensures that the snapshotting doesn't
affect current tracing on/off settings.

Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Shuah Khan <shuah@xxxxxxxxxx>
Cc: linux-kselftest@xxxxxxxxxxxxxxx
---
 .../selftests/ftrace/test.d/00basic/snapshot.tc    |   28 ++++++++++++++++++++
 1 file changed, 28 insertions(+)
 create mode 100644 tools/testing/selftests/ftrace/test.d/00basic/snapshot.tc

diff --git a/tools/testing/selftests/ftrace/test.d/00basic/snapshot.tc b/tools/testing/selftests/ftrace/test.d/00basic/snapshot.tc
new file mode 100644
index 000000000000..3b1f45e13a2e
--- /dev/null
+++ b/tools/testing/selftests/ftrace/test.d/00basic/snapshot.tc
@@ -0,0 +1,28 @@
+#!/bin/sh
+# description: Snapshot and tracing setting
+# flags: instance
+
+[ ! -f snapshot ] && exit_unsupported
+
+echo "Set tracing off"
+echo 0 > tracing_on
+
+echo "Allocate and take a snapshot"
+echo 1 > snapshot
+
+# Since trace buffer is empty, snapshot is also empty, but allocated
+grep -q "Snapshot is allocated" snapshot
+
+echo "Ensure keep tracing off"
+test `cat tracing_on` -eq 0
+
+echo "Set tracing on"
+echo 1 > tracing_on
+
+echo "Take a snapshot again"
+echo 1 > snapshot
+
+echo "Ensure keep tracing on"
+test `cat tracing_on` -eq 1
+
+exit 0