[PATCH] rcutorture: Copy out ftrace into its own console file

[Joel Fernandes (Google)]

From: Joel <agnel.joel@xxxxxxxxx>

Often times it is difficult to jump to the ftrace buffers and treat it
independently during debugging. Copy the contents of the buffers into
its own file.

Signed-off-by: Joel Fernandes (Google) <joel@xxxxxxxxxxxxxxxxx>
---
 .../selftests/rcutorture/bin/functions.sh     | 24 +++++++++++++++++++
 .../selftests/rcutorture/bin/parse-console.sh |  7 ++++++
 2 files changed, 31 insertions(+)
 mode change 100644 => 100755 tools/testing/selftests/rcutorture/bin/functions.sh

diff --git a/tools/testing/selftests/rcutorture/bin/functions.sh b/tools/testing/selftests/rcutorture/bin/functions.sh
old mode 100644
new mode 100755
index b8e2ea23cb3f..2ec4ab87a7f0
--- a/tools/testing/selftests/rcutorture/bin/functions.sh
+++ b/tools/testing/selftests/rcutorture/bin/functions.sh
@@ -331,3 +331,27 @@ specify_qemu_net () {
 		echo $1 -net none
 	fi
 }
+
+# Extract the ftrace output from the console log output
+# The ftrace output looks in the logs looks like:
+# Dumping ftrace buffer:
+# ---------------------------------
+# [...]
+# ---------------------------------
+extract_ftrace_from_console() {
+        awk '
+        /Dumping ftrace buffer:/ {
+        capture = 1
+        next
+    }
+    /---------------------------------/ {
+        if(capture == 1) {
+            capture = 2
+            next
+        } else if(capture == 2) {
+            capture = 0
+        }
+    }
+    capture == 2
+    ' "$1";
+}
diff --git a/tools/testing/selftests/rcutorture/bin/parse-console.sh b/tools/testing/selftests/rcutorture/bin/parse-console.sh
index 9ab0f6bc172c..e3d2f69ec0fb 100755
--- a/tools/testing/selftests/rcutorture/bin/parse-console.sh
+++ b/tools/testing/selftests/rcutorture/bin/parse-console.sh
@@ -182,3 +182,10 @@ if ! test -s $file.diags
 then
 	rm -f $file.diags
 fi
+
+# Call extract_ftrace_from_console function, if the output is empty,
+# don't create $file.ftrace. Otherwise output the results to $file.ftrace
+extract_ftrace_from_console $file > $file.ftrace
+if [ ! -s $file.ftrace ]; then
+	rm -f $file.ftrace
+fi
-- 
2.41.0.640.ga95def55d0-goog