On 2021/6/2 上午12:42, Darrick J. Wong wrote:
On Tue, Jun 01, 2021 at 03:31:33PM +0800, Qu Wenruo wrote:
Sometimes developers want trace dump for certain test cases.
Normally I just add "trace-cmd" calls in "check", but it would be much
Heh, so do I!
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.
I... did not know one could /have/ separate instances.
So did I, until I checked the code of "trace-cmd clear".
Signed-off-by: Qu Wenruo <wqu@xxxxxxxx>
---
check | 12 +++++++-
common/ftrace | 82 +++++++++++++++++++++++++++++++++++++++++++++++++++
common/rc | 1 +
3 files changed, 94 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 > $DEBUGFS_MNT/clear_warn_once) > /dev/null 2>&1
+ # Clear previous trace and start new trace
+ _clear_trace_buffers
+ _start_trace
How do you actually turn on specific tracepoints?
Normally I use trace_printk(), thus no need to enable it manually.
Or is the idea here to capture trace data for each test in a separate
file, and it's up to the ./check caller to set that up?
My idea is, it should be the QA guy to set it up.
Either using my stupid trace_printk() way, or enable those events before
running the test.
+
if [ "$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 $n_bad + 1`
tc_status="fail"
diff --git a/common/ftrace b/common/ftrace
new file mode 100644
index 00000000..36886484
--- /dev/null
+++ b/common/ftrace
@@ -0,0 +1,82 @@
+#
+# Common ftrace related functions
+#
New file needs a SPDX header.
Oh, forgot that.
+
+TRACE_DIR="/sys/kernel/debug/tracing"
+
+_clear_trace_buffers()
+{
+ if [ ! -d "${TRACE_DIR}" ]; then
+ return
+ fi
+
+ # Clear the main buffer
+ echo 0 > "${TRACE_DIR}/trace"
If one were already running trace-cmd record, will this mess up its
ability to collect trace data?
I guess it may.
But that shouldn't be a problem, all existing buffers are before running
the tests, thus should be considered as noise.
+
+ # Clear each instance buffer
+ for i in $(ls "${TRACE_DIR}/instances"); do
+ echo 0 > "${i}/trace"
+ done
+}
+
+_start_trace()
+{
+ instance=$1
local instance="$1", please don't pollute the caller's environment.
Oh, forgot it again...
+
+ if [ ! -d "${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()
+{
+ instance=$1
+
+ if [ ! -d "${TRACE_DIR}" ]; then
+ return
+ fi
+
+ if [ -z "${instance}" ]; then
+ echo 0 > "${TRACE_DIR}/tracing_on"
+ else
+ mkdir -p "${TRACE_DIR}/instances/${instance}"
Er, what's the logic here? Ensure that the instance exist so that we
can disable it?
Oh, right, we should exit directly...
This part is copies from _start_trace() obviously...
Thanks,
Qu
--D
+ echo 0 > "${TRACE_DIR}/instances/${instance}/tracing_on"
+ fi
+}
+
+_remove_empty_trace()
+{
+ file="$1"
+ if [ ! -f "$file" ]; then
+ return
+ fi
+
+ if [ -z "$(head -n 15 $file | sed '/^#/d')" ]; then
+ rm $file
+ fi
+}
+
+_copy_trace()
+{
+ dest="$1"
+ 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 "$dest"
+}
diff --git a/common/rc b/common/rc
index 919028ef..f9de1517 100644
--- a/common/rc
+++ b/common/rc
@@ -3,6 +3,7 @@
# Copyright (c) 2000-2006 Silicon Graphics, Inc. All Rights Reserved.
. common/config
+. common/ftrace
BC=$(which bc 2> /dev/null) || BC=
--
2.31.1
