Sometimes developers want trace dump for certain test cases.
Normally I just add "trace-cmd" calls in "check", but it would be much
better to let fstests to support ftrace dumping.
This patchset will add basic ftrace dumping support by:
- Clear all buffers before running each test
- Start tracing before running each test
- End tracing after test finished
- Copy the trace to "$seqres.trace" if needed
The condition is either:
* $KEEP_TRACE environment is set to "yes"
* The test case failed
Currently we only support the main ftrace buffer, but all supporting
functions have support for ftrace instances, for later expansion.
Signed-off-by: Qu Wenruo <wqu@xxxxxxxx>
---
Changelog:
v2:
- Add explanation in "common/config" for how to use it
- Make variables local
- Don't create the instance when clearing buffers
---
check | 12 +++++++-
common/config | 8 +++++
common/ftrace | 83 +++++++++++++++++++++++++++++++++++++++++++++++++++
common/rc | 1 +
4 files changed, 103 insertions(+), 1 deletion(-)
create mode 100644 common/ftrace
diff --git a/check b/check
index ba192042..0a09dcf9 100755
--- a/check
+++ b/check
@@ -801,7 +801,7 @@ function run_section()
fi
# really going to try and run this one
- rm -f $seqres.out.bad
+ rm -f $seqres.out.bad $seqres.trace
# check if we really should run it
_expunge_test $seqnum
@@ -839,6 +839,10 @@ function run_section()
# to be reported for each test
(echo 1 > $DEBUGFS_MNT/clear_warn_once) > /dev/null 2>&1
+ # Clear previous trace and start new trace
+ _clear_trace_buffers
+ _start_trace
+
if [ "$DUMP_OUTPUT" = true ]; then
_run_seq 2>&1 | tee $tmp.out
# Because $? would get tee's return code
@@ -848,6 +852,11 @@ function run_section()
sts=$?
fi
+ _end_trace
+ if [ "$KEEP_TRACE" == "yes" ]; then
+ _copy_trace "$seqres.trace"
+ fi
+
if [ -f core ]; then
_dump_err_cont "[dumped core]"
mv core $RESULT_BASE/$seqnum.core
@@ -932,6 +941,7 @@ function run_section()
# make sure we record the status of the last test we ran.
if $err ; then
+ _copy_trace "$seqres.trace"
bad="$bad $seqnum"
n_bad=`expr $n_bad + 1`
tc_status="fail"
diff --git a/common/config b/common/config
index ad1c9eb0..4dec2bfa 100644
--- a/common/config
+++ b/common/config
@@ -25,6 +25,14 @@
# KEEP_DMESG - whether to keep all dmesg for each test case.
# yes: keep all dmesg
# no: only keep dmesg with error/warning (default)
+# KEEP_TRACE - whether to keep all non-empty ftrace buffer for each test case.
+# yes: keep all non-empty ftrace buffer
+# no: only keep non-empty ftrace buffer when the test fails (default)
+#
+# NOTE: to dump ftrace buffer one needs to enable ftrace
+# events or add custom trace_printk() into the fs code.
+# And since fstest will clear buffer before running one
+# test case, existing trace-cmd can be interrupted.
#
# - These can be added to $HOST_CONFIG_DIR (witch default to ./config)
# below or a separate local configuration file can be used (using
diff --git a/common/ftrace b/common/ftrace
new file mode 100644
index 00000000..9eec0f53
--- /dev/null
+++ b/common/ftrace
@@ -0,0 +1,83 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Common ftrace related helpers
+#
+
+TRACE_DIR="/sys/kernel/debug/tracing"
+
+_clear_trace_buffers()
+{
+ if [ ! -d "${TRACE_DIR}" ]; then
+ return
+ fi
+
+ # Clear the main buffer
+ echo 0 > "${TRACE_DIR}/trace"
+
+ # Clear each instance buffer
+ for i in $(ls "${TRACE_DIR}/instances"); do
+ echo 0 > "${i}/trace"
+ done
+}
+
+_start_trace()
+{
+ local instance=$1
+
+ if [ ! -d "${TRACE_DIR}" ]; then
+ return
+ fi
+
+ if [ -z "${instance}" ]; then
+ echo 1 > "${TRACE_DIR}/tracing_on"
+ else
+ mkdir -p "${TRACE_DIR}/instances/${instance}"
+ echo 1 > "${TRACE_DIR}/instances/${instance}/tracing_on"
+ fi
+}
+
+_end_trace()
+{
+ local instance=$1
+
+ if [ ! -d "${TRACE_DIR}" ]; then
+ return
+ fi
+
+ if [ -z "${instance}" ]; then
+ echo 0 > "${TRACE_DIR}/tracing_on"
+ elif [ -d "${TRACE_DIR}/instances/${instance}" ]; then
+ echo 0 > "${TRACE_DIR}/instances/${instance}/tracing_on"
+ fi
+}
+
+_remove_empty_trace()
+{
+ local file="$1"
+
+ if [ ! -f "$file" ]; then
+ return
+ fi
+
+ if [ -z "$(head -n 15 $file | sed '/^#/d')" ]; then
+ rm $file
+ fi
+}
+
+_copy_trace()
+{
+ local dest="$1"
+ local instance="$2"
+
+ if [ ! -d "${TRACE_DIR}" ]; then
+ return
+ fi
+
+ if [ -z "${instance}" ]; then
+ cp "${TRACE_DIR}/trace" "$dest"
+ elif [ -d "${TRACE_DIR}/instances/${instance}" ]; then
+ cp "${TRACE_DIR}/instances/${instance}/trace" "$dest"
+ fi
+
+ _remove_empty_trace "$dest"
+}
diff --git a/common/rc b/common/rc
index a0aa7300..d828dca8 100644
--- a/common/rc
+++ b/common/rc
@@ -3,6 +3,7 @@
# Copyright (c) 2000-2006 Silicon Graphics, Inc. All Rights Reserved.
. common/config
+. common/ftrace
BC=$(which bc 2> /dev/null) || BC=
--
2.31.1
